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[PATCH v4 00/12] mm/gup: track FOLL_PIN pages

by John Hubbard

Hi, Here's an update after the latest round of reviews from Kirill and Jan. There is a git repo and branch, for convenience in reviewing: git@github.com:johnhubbard/linux.git track_user_pages_v4 I'm particularly pleased that the /proc/vmstat items are now available in all configurations, seeing as how I was looking (in vain) for that information during a recent investigation of a remotely reported problem. ============================================================ Changes since v3: * Rebased onto latest linux.git * Added ACKs and reviewed-by's from Kirill Shutemov and Jan Kara. * /proc/vmstat: * Renamed items, after realizing that I hate the previous names: nr_foll_pin_requested --> nr_foll_pin_acquired nr_foll_pin_returned --> nr_foll_pin_released * Removed the CONFIG_DEBUG_VM guard, and collapsed away a wrapper routine: now just calls mod_node_page_state() directly. * Tweaked the WARN_ON_ONCE() statements in mm/hugetlb.c to be more informative, and added comments above them as well. * Fixed gup_benchmark: signed int --> unsigned long. * One or two minor formatting changes. ============================================================ Changes since v2: * Rebased onto linux.git, because the akpm tree for 5.6 has been merged. * Split the tracking patch into even more patches, as requested. * Merged Matthew Wilcox's dump_page() changes into mine, as part of the first patch. * Renamed: page_dma_pinned() --> page_maybe_dma_pinned(), in response to Kirill Shutemov's review. * Moved a WARN to the top of a routine, and fixed a typo in the commit description of patch #7, also as suggested by Kirill. ============================================================ Changes since v1: * Split the tracking patch into 6 smaller patches * Rebased onto today's linux-next/akpm (there weren't any conflicts). * Fixed an "unsigned int" vs. "int" problem in gup_benchmark, reported by Nathan Chancellor. (I don't see it in my local builds, probably because they use gcc, but an LLVM test found the mismatch.) * Fixed a huge page pincount problem (add/subtract vs. increment/decrement), spotted by Jan Kara. ============================================================ There is a reasonable case to be made for merging two of the patches (patches 7 and 8), given that patch 7 provides tracking that has upper limits on the number of pins that can be done with huge pages. Let me know if anyone wants those merged, but unless there is some weird chance of someone grabbing patch 7 and not patch 8, I don't really see the need. Meanwhile, it's easier to review in this form. Also, patch 3 has been revived. Earlier reviewers asked for it to be merged into the tracking patch (one cannot please everyone, heh), but now it's back out on it's own. This activates tracking of FOLL_PIN pages. This is in support of fixing the get_user_pages()+DMA problem described in [1]-[4]. FOLL_PIN support is now in the main linux tree. However, the patch to use FOLL_PIN to track pages was *not* submitted, because Leon saw an RDMA test suite failure that involved (I think) page refcount overflows when huge pages were used. This patch definitively solves that kind of overflow problem, by adding an exact pincount, for compound pages (of order > 1), in the 3rd struct page of a compound page. If available, that form of pincounting is used, instead of the GUP_PIN_COUNTING_BIAS approach. Thanks again to Jan Kara for that idea. Other interesting changes: * dump_page(): added one, or two new things to report for compound pages: head refcount (for all compound pages), and map_pincount (for compound pages of order > 1). * Documentation/core-api/pin_user_pages.rst: removed the "TODO" for the huge page refcount upper limit problems, and added notes about how it works now. Also added a note about the dump_page() enhancements. * Added some comments in gup.c and mm.h, to explain that there are two ways to count pinned pages: exact (for compound pages of order > 1) and fuzzy (GUP_PIN_COUNTING_BIAS: for all other pages). ============================================================ General notes about the tracking patch: This is a prerequisite to solving the problem of proper interactions between file-backed pages, and [R]DMA activities, as discussed in [1], [2], [3], [4] and in a remarkable number of email threads since about 2017. :) In contrast to earlier approaches, the page tracking can be incrementally applied to the kernel call sites that, until now, have been simply calling get_user_pages() ("gup"). In other words, opt-in by changing from this: get_user_pages() (sets FOLL_GET) put_page() to this: pin_user_pages() (sets FOLL_PIN) unpin_user_page() ============================================================ Next steps: * Convert more subsystems from get_user_pages() to pin_user_pages(). * Work with Ira and others to connect this all up with file system leases. [1] Some slow progress on get_user_pages() (Apr 2, 2019): https://lwn.net/Articles/784574/ [2] DMA and get_user_pages() (LPC: Dec 12, 2018): https://lwn.net/Articles/774411/ [3] The trouble with get_user_pages() (Apr 30, 2018): https://lwn.net/Articles/753027/ [4] LWN kernel index: get_user_pages() https://lwn.net/Kernel/Index/#Memory_management-get_user_pages John Hubbard (12): mm: dump_page(): better diagnostics for compound pages mm/gup: split get_user_pages_remote() into two routines mm/gup: pass a flags arg to __gup_device_* functions mm: introduce page_ref_sub_return() mm/gup: pass gup flags to two more routines mm/gup: require FOLL_GET for get_user_pages_fast() mm/gup: track FOLL_PIN pages mm/gup: page->hpage_pinned_refcount: exact pin counts for huge pages mm: dump_page(): better diagnostics for huge pinned pages mm/gup: /proc/vmstat: pin_user_pages (FOLL_PIN) reporting mm/gup_benchmark: support pin_user_pages() and related calls selftests/vm: run_vmtests: invoke gup_benchmark with basic FOLL_PIN coverage Documentation/core-api/pin_user_pages.rst | 59 ++- include/linux/mm.h | 108 ++++- include/linux/mm_types.h | 7 +- include/linux/mmzone.h | 2 + include/linux/page_ref.h | 9 + mm/debug.c | 61 ++- mm/gup.c | 448 ++++++++++++++++----- mm/gup_benchmark.c | 71 +++- mm/huge_memory.c | 29 +- mm/hugetlb.c | 60 ++- mm/page_alloc.c | 2 + mm/rmap.c | 6 + mm/vmstat.c | 2 + tools/testing/selftests/vm/gup_benchmark.c | 15 +- tools/testing/selftests/vm/run_vmtests | 22 + 15 files changed, 721 insertions(+), 180 deletions(-) -- 2.25.0

4 years, 11 months

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[PATCH 1/3] kvm: mmu: Replace unsigned with unsigned int for PTE access

by Ben Gardon

There are several functions which pass an access permission mask for SPTEs as an unsigned. This works, but checkpatch complains about it. Switch the occurrences of unsigned to unsigned int to satisfy checkpatch. No functional change expected. Tested by running kvm-unit-tests on an Intel Haswell machine. This commit introduced no new failures. This commit can be viewed in Gerrit at: https://linux-review.googlesource.com/c/virt/kvm/kvm/+/2358 Signed-off-by: Ben Gardon <bgardon(a)google.com> Reviewed-by: Oliver Upton <oupton(a)google.com> --- arch/x86/kvm/mmu/mmu.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 84eeb61d06aa3..a9c593dec49bf 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -452,7 +452,7 @@ static u64 get_mmio_spte_generation(u64 spte) } static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn, - unsigned access) + unsigned int access) { u64 gen = kvm_vcpu_memslots(vcpu)->generation & MMIO_SPTE_GEN_MASK; u64 mask = generation_mmio_spte_mask(gen); @@ -484,7 +484,7 @@ static unsigned get_mmio_spte_access(u64 spte) } static bool set_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn, - kvm_pfn_t pfn, unsigned access) + kvm_pfn_t pfn, unsigned int access) { if (unlikely(is_noslot_pfn(pfn))) { mark_mmio_spte(vcpu, sptep, gfn, access); @@ -2475,7 +2475,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gva_t gaddr, unsigned level, int direct, - unsigned access) + unsigned int access) { union kvm_mmu_page_role role; unsigned quadrant; @@ -2990,7 +2990,7 @@ static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) #define SET_SPTE_NEED_REMOTE_TLB_FLUSH BIT(1) static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, - unsigned pte_access, int level, + unsigned int pte_access, int level, gfn_t gfn, kvm_pfn_t pfn, bool speculative, bool can_unsync, bool host_writable) { @@ -3081,9 +3081,10 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, return ret; } -static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access, - int write_fault, int level, gfn_t gfn, kvm_pfn_t pfn, - bool speculative, bool host_writable) +static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, + unsigned int pte_access, int write_fault, int level, + gfn_t gfn, kvm_pfn_t pfn, bool speculative, + bool host_writable) { int was_rmapped = 0; int rmap_count; @@ -3165,7 +3166,7 @@ static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu, { struct page *pages[PTE_PREFETCH_NUM]; struct kvm_memory_slot *slot; - unsigned access = sp->role.access; + unsigned int access = sp->role.access; int i, ret; gfn_t gfn; @@ -3400,7 +3401,8 @@ static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn) } static bool handle_abnormal_pfn(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn, - kvm_pfn_t pfn, unsigned access, int *ret_val) + kvm_pfn_t pfn, unsigned int access, + int *ret_val) { /* The pfn is invalid, report the error! */ if (unlikely(is_error_pfn(pfn))) { @@ -4005,7 +4007,7 @@ static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct) if (is_mmio_spte(spte)) { gfn_t gfn = get_mmio_spte_gfn(spte); - unsigned access = get_mmio_spte_access(spte); + unsigned int access = get_mmio_spte_access(spte); if (!check_mmio_spte(vcpu, spte)) return RET_PF_INVALID; @@ -4349,7 +4351,7 @@ static void inject_page_fault(struct kvm_vcpu *vcpu, } static bool sync_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn, - unsigned access, int *nr_present) + unsigned int access, int *nr_present) { if (unlikely(is_mmio_spte(*sptep))) { if (gfn != get_mmio_spte_gfn(*sptep)) { -- 2.25.0.341.g760bfbb309-goog

4 years, 11 months

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[PATCH v6 6/6] selftests/cgroup: add tests for cloning into cgroups

by Christian Brauner

Expand the cgroup test-suite to include tests for CLONE_INTO_CGROUP. This adds the following tests: - CLONE_INTO_CGROUP manages to clone a process directly into a correctly delegated cgroup - CLONE_INTO_CGROUP fails to clone a process into a cgroup that has been removed after we've opened an fd to it - CLONE_INTO_CGROUP fails to clone a process into an invalid domain cgroup - CLONE_INTO_CGROUP adheres to the no internal process constraint - CLONE_INTO_CGROUP works with the freezer feature Cc: Tejun Heo <tj(a)kernel.org> Cc: Shuah Khan <shuah(a)kernel.org> Cc: cgroups(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org Acked-by: Roman Gushchin <guro(a)fb.com> Signed-off-by: Christian Brauner <christian.brauner(a)ubuntu.com> --- /* v1 */ Link: https://lore.kernel.org/r/20191218173516.7875-4-christian.brauner@ubuntu.com /* v2 */ Link: https://lore.kernel.org/r/20191223061504.28716-4-christian.brauner@ubuntu.c… unchanged /* v3 */ Link: https://lore.kernel.org/r/20200117002143.15559-6-christian.brauner@ubuntu.c… unchanged /* v4 */ Link: https://lore.kernel.org/r/20200117181219.14542-7-christian.brauner@ubuntu.c… unchanged /* v5 */ Link: https://lore.kernel.org/r/20200121154844.411-7-christian.brauner@ubuntu.com unchanged - Christian Brauner <christian.brauner(a)ubuntu.com>: - add Acked-by: Roman Gushchin <guro(a)fb.com> /* v6 */ unchanged --- tools/testing/selftests/cgroup/Makefile | 6 +- tools/testing/selftests/cgroup/cgroup_util.c | 126 ++++++++++++++++++ tools/testing/selftests/cgroup/cgroup_util.h | 4 + tools/testing/selftests/cgroup/test_core.c | 64 +++++++++ .../selftests/clone3/clone3_selftests.h | 19 ++- 5 files changed, 214 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile index 66aafe1f5746..967f268fde74 100644 --- a/tools/testing/selftests/cgroup/Makefile +++ b/tools/testing/selftests/cgroup/Makefile @@ -11,6 +11,6 @@ TEST_GEN_PROGS += test_freezer include ../lib.mk -$(OUTPUT)/test_memcontrol: cgroup_util.c -$(OUTPUT)/test_core: cgroup_util.c -$(OUTPUT)/test_freezer: cgroup_util.c +$(OUTPUT)/test_memcontrol: cgroup_util.c ../clone3/clone3_selftests.h +$(OUTPUT)/test_core: cgroup_util.c ../clone3/clone3_selftests.h +$(OUTPUT)/test_freezer: cgroup_util.c ../clone3/clone3_selftests.h diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c index 8f7131dcf1ff..8a637ca7d73a 100644 --- a/tools/testing/selftests/cgroup/cgroup_util.c +++ b/tools/testing/selftests/cgroup/cgroup_util.c @@ -15,6 +15,7 @@ #include <unistd.h> #include "cgroup_util.h" +#include "../clone3/clone3_selftests.h" static ssize_t read_text(const char *path, char *buf, size_t max_len) { @@ -331,12 +332,112 @@ int cg_run(const char *cgroup, } } +pid_t clone_into_cgroup(int cgroup_fd) +{ +#ifdef CLONE_ARGS_SIZE_VER2 + pid_t pid; + + struct clone_args args = { + .flags = CLONE_INTO_CGROUP, + .exit_signal = SIGCHLD, + .cgroup = cgroup_fd, + }; + + pid = sys_clone3(&args, sizeof(struct clone_args)); + /* + * Verify that this is a genuine test failure: + * ENOSYS -> clone3() not available + * E2BIG -> CLONE_INTO_CGROUP not available + */ + if (pid < 0 && (errno == ENOSYS || errno == E2BIG)) + goto pretend_enosys; + + return pid; + +pretend_enosys: +#endif + errno = ENOSYS; + return -ENOSYS; +} + +int clone_reap(pid_t pid, int options) +{ + int ret; + siginfo_t info = { + .si_signo = 0, + }; + +again: + ret = waitid(P_PID, pid, &info, options | __WALL | __WNOTHREAD); + if (ret < 0) { + if (errno == EINTR) + goto again; + return -1; + } + + if (options & WEXITED) { + if (WIFEXITED(info.si_status)) + return WEXITSTATUS(info.si_status); + } + + if (options & WSTOPPED) { + if (WIFSTOPPED(info.si_status)) + return WSTOPSIG(info.si_status); + } + + if (options & WCONTINUED) { + if (WIFCONTINUED(info.si_status)) + return 0; + } + + return -1; +} + +int dirfd_open_opath(const char *dir) +{ + return open(dir, O_DIRECTORY | O_CLOEXEC | O_NOFOLLOW | O_PATH); +} + +#define close_prot_errno(fd) \ + if (fd >= 0) { \ + int _e_ = errno; \ + close(fd); \ + errno = _e_; \ + } + +static int clone_into_cgroup_run_nowait(const char *cgroup, + int (*fn)(const char *cgroup, void *arg), + void *arg) +{ + int cgroup_fd; + pid_t pid; + + cgroup_fd = dirfd_open_opath(cgroup); + if (cgroup_fd < 0) + return -1; + + pid = clone_into_cgroup(cgroup_fd); + close_prot_errno(cgroup_fd); + if (pid == 0) + exit(fn(cgroup, arg)); + + return pid; +} + int cg_run_nowait(const char *cgroup, int (*fn)(const char *cgroup, void *arg), void *arg) { int pid; + pid = clone_into_cgroup_run_nowait(cgroup, fn, arg); + if (pid > 0) + return pid; + + /* Genuine test failure. */ + if (pid < 0 && errno != ENOSYS) + return -1; + pid = fork(); if (pid == 0) { char buf[64]; @@ -450,3 +551,28 @@ int proc_read_strstr(int pid, bool thread, const char *item, const char *needle) return strstr(buf, needle) ? 0 : -1; } + +int clone_into_cgroup_run_wait(const char *cgroup) +{ + int cgroup_fd; + pid_t pid; + + cgroup_fd = dirfd_open_opath(cgroup); + if (cgroup_fd < 0) + return -1; + + pid = clone_into_cgroup(cgroup_fd); + close_prot_errno(cgroup_fd); + if (pid < 0) + return -1; + + if (pid == 0) + exit(EXIT_SUCCESS); + + /* + * We don't care whether this fails. We only care whether the initial + * clone succeeded. + */ + (void)clone_reap(pid, WEXITED); + return 0; +} diff --git a/tools/testing/selftests/cgroup/cgroup_util.h b/tools/testing/selftests/cgroup/cgroup_util.h index 49c54fbdb229..5a1305dd1f0b 100644 --- a/tools/testing/selftests/cgroup/cgroup_util.h +++ b/tools/testing/selftests/cgroup/cgroup_util.h @@ -50,3 +50,7 @@ extern int cg_wait_for_proc_count(const char *cgroup, int count); extern int cg_killall(const char *cgroup); extern ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size); extern int proc_read_strstr(int pid, bool thread, const char *item, const char *needle); +extern pid_t clone_into_cgroup(int cgroup_fd); +extern int clone_reap(pid_t pid, int options); +extern int clone_into_cgroup_run_wait(const char *cgroup); +extern int dirfd_open_opath(const char *dir); diff --git a/tools/testing/selftests/cgroup/test_core.c b/tools/testing/selftests/cgroup/test_core.c index c5ca669feb2b..96e016ccafe0 100644 --- a/tools/testing/selftests/cgroup/test_core.c +++ b/tools/testing/selftests/cgroup/test_core.c @@ -25,8 +25,11 @@ static int test_cgcore_populated(const char *root) { int ret = KSFT_FAIL; + int err; char *cg_test_a = NULL, *cg_test_b = NULL; char *cg_test_c = NULL, *cg_test_d = NULL; + int cgroup_fd = -EBADF; + pid_t pid; cg_test_a = cg_name(root, "cg_test_a"); cg_test_b = cg_name(root, "cg_test_a/cg_test_b"); @@ -78,6 +81,52 @@ static int test_cgcore_populated(const char *root) if (cg_read_strcmp(cg_test_d, "cgroup.events", "populated 0\n")) goto cleanup; + /* Test that we can directly clone into a new cgroup. */ + cgroup_fd = dirfd_open_opath(cg_test_d); + if (cgroup_fd < 0) + goto cleanup; + + pid = clone_into_cgroup(cgroup_fd); + if (pid < 0) { + if (errno == ENOSYS) + goto cleanup_pass; + goto cleanup; + } + + if (pid == 0) { + if (raise(SIGSTOP)) + exit(EXIT_FAILURE); + exit(EXIT_SUCCESS); + } + + err = cg_read_strcmp(cg_test_d, "cgroup.events", "populated 1\n"); + + (void)clone_reap(pid, WSTOPPED); + (void)kill(pid, SIGCONT); + (void)clone_reap(pid, WEXITED); + + if (err) + goto cleanup; + + if (cg_read_strcmp(cg_test_d, "cgroup.events", "populated 0\n")) + goto cleanup; + + /* Remove cgroup. */ + if (cg_test_d) { + cg_destroy(cg_test_d); + free(cg_test_d); + cg_test_d = NULL; + } + + pid = clone_into_cgroup(cgroup_fd); + if (pid < 0) + goto cleanup_pass; + if (pid == 0) + exit(EXIT_SUCCESS); + (void)clone_reap(pid, WEXITED); + goto cleanup; + +cleanup_pass: ret = KSFT_PASS; cleanup: @@ -93,6 +142,8 @@ static int test_cgcore_populated(const char *root) free(cg_test_c); free(cg_test_b); free(cg_test_a); + if (cgroup_fd >= 0) + close(cgroup_fd); return ret; } @@ -136,6 +187,16 @@ static int test_cgcore_invalid_domain(const char *root) if (errno != EOPNOTSUPP) goto cleanup; + if (!clone_into_cgroup_run_wait(child)) + goto cleanup; + + if (errno == ENOSYS) + goto cleanup_pass; + + if (errno != EOPNOTSUPP) + goto cleanup; + +cleanup_pass: ret = KSFT_PASS; cleanup: @@ -345,6 +406,9 @@ static int test_cgcore_internal_process_constraint(const char *root) if (!cg_enter_current(parent)) goto cleanup; + if (!clone_into_cgroup_run_wait(parent)) + goto cleanup; + ret = KSFT_PASS; cleanup: diff --git a/tools/testing/selftests/clone3/clone3_selftests.h b/tools/testing/selftests/clone3/clone3_selftests.h index a3f2c8ad8bcc..91c1a78ddb39 100644 --- a/tools/testing/selftests/clone3/clone3_selftests.h +++ b/tools/testing/selftests/clone3/clone3_selftests.h @@ -5,12 +5,24 @@ #define _GNU_SOURCE #include <sched.h> +#include <linux/sched.h> +#include <linux/types.h> #include <stdint.h> #include <syscall.h> -#include <linux/types.h> +#include <sys/wait.h> + +#include "../kselftest.h" #define ptr_to_u64(ptr) ((__u64)((uintptr_t)(ptr))) +#ifndef CLONE_INTO_CGROUP +#define CLONE_INTO_CGROUP 0x200000000ULL /* Clone into a specific cgroup given the right permissions. */ +#endif + +#ifndef CLONE_ARGS_SIZE_VER0 +#define CLONE_ARGS_SIZE_VER0 64 +#endif + #ifndef __NR_clone3 #define __NR_clone3 -1 struct clone_args { @@ -22,10 +34,13 @@ struct clone_args { __aligned_u64 stack; __aligned_u64 stack_size; __aligned_u64 tls; +#define CLONE_ARGS_SIZE_VER1 80 __aligned_u64 set_tid; __aligned_u64 set_tid_size; +#define CLONE_ARGS_SIZE_VER2 88 + __aligned_u64 cgroup; }; -#endif +#endif /* __NR_clone3 */ static pid_t sys_clone3(struct clone_args *args, size_t size) { -- 2.25.0

4 years, 11 months

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[PATCH v25 20/21] selftests/x86: Add vDSO selftest for SGX

by Jarkko Sakkinen

Expand the selftest by invoking the enclave by using __vdso_sgx_enter_enclave() in addition to direct ENCLS[EENTER]. Cc: linux-kselftest(a)vger.kernel.org Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen(a)linux.intel.com> --- tools/testing/selftests/x86/sgx/main.c | 132 +++++++++++++++++++++ tools/testing/selftests/x86/sgx/sgx_call.S | 43 +++++++ tools/testing/selftests/x86/sgx/sgx_call.h | 3 + 3 files changed, 178 insertions(+) diff --git a/tools/testing/selftests/x86/sgx/main.c b/tools/testing/selftests/x86/sgx/main.c index 48ed5fdfb3cb..d97cc3cf0093 100644 --- a/tools/testing/selftests/x86/sgx/main.c +++ b/tools/testing/selftests/x86/sgx/main.c @@ -21,6 +21,109 @@ #define PAGE_SIZE 4096 static const uint64_t MAGIC = 0x1122334455667788ULL; +void *eenter; + +struct vdso_symtab { + Elf64_Sym *elf_symtab; + const char *elf_symstrtab; + Elf64_Word *elf_hashtab; +}; + +static void *vdso_get_base_addr(char *envp[]) +{ + Elf64_auxv_t *auxv; + int i; + + for (i = 0; envp[i]; i++) + ; + + auxv = (Elf64_auxv_t *)&envp[i + 1]; + + for (i = 0; auxv[i].a_type != AT_NULL; i++) { + if (auxv[i].a_type == AT_SYSINFO_EHDR) + return (void *)auxv[i].a_un.a_val; + } + + return NULL; +} + +static Elf64_Dyn *vdso_get_dyntab(void *addr) +{ + Elf64_Ehdr *ehdr = addr; + Elf64_Phdr *phdrtab = addr + ehdr->e_phoff; + int i; + + for (i = 0; i < ehdr->e_phnum; i++) + if (phdrtab[i].p_type == PT_DYNAMIC) + return addr + phdrtab[i].p_offset; + + return NULL; +} + +static void *vdso_get_dyn(void *addr, Elf64_Dyn *dyntab, Elf64_Sxword tag) +{ + int i; + + for (i = 0; dyntab[i].d_tag != DT_NULL; i++) + if (dyntab[i].d_tag == tag) + return addr + dyntab[i].d_un.d_ptr; + + return NULL; +} + +static bool vdso_get_symtab(void *addr, struct vdso_symtab *symtab) +{ + Elf64_Dyn *dyntab = vdso_get_dyntab(addr); + + symtab->elf_symtab = vdso_get_dyn(addr, dyntab, DT_SYMTAB); + if (!symtab->elf_symtab) + return false; + + symtab->elf_symstrtab = vdso_get_dyn(addr, dyntab, DT_STRTAB); + if (!symtab->elf_symstrtab) + return false; + + symtab->elf_hashtab = vdso_get_dyn(addr, dyntab, DT_HASH); + if (!symtab->elf_hashtab) + return false; + + return true; +} + +static unsigned long elf_sym_hash(const char *name) +{ + unsigned long h = 0, high; + + while (*name) { + h = (h << 4) + *name++; + high = h & 0xf0000000; + + if (high) + h ^= high >> 24; + + h &= ~high; + } + + return h; +} + +static Elf64_Sym *vdso_symtab_get(struct vdso_symtab *symtab, const char *name) +{ + Elf64_Word bucketnum = symtab->elf_hashtab[0]; + Elf64_Word *buckettab = &symtab->elf_hashtab[2]; + Elf64_Word *chaintab = &symtab->elf_hashtab[2 + bucketnum]; + Elf64_Sym *sym; + Elf64_Word i; + + for (i = buckettab[elf_sym_hash(name) % bucketnum]; i != STN_UNDEF; + i = chaintab[i]) { + sym = &symtab->elf_symtab[i]; + if (!strcmp(name, &symtab->elf_symstrtab[sym->st_name])) + return sym; + } + + return NULL; +} static bool encl_create(int dev_fd, unsigned long bin_size, struct sgx_secs *secs) @@ -218,10 +321,14 @@ bool load_sigstruct(const char *path, void *sigstruct) int main(int argc, char *argv[], char *envp[]) { + struct sgx_enclave_exception exception; struct sgx_sigstruct sigstruct; + struct vdso_symtab symtab; + Elf64_Sym *eenter_sym; struct sgx_secs secs; uint64_t result = 0; off_t bin_size; + void *addr; void *bin; if (!encl_data_map("encl.bin", &bin, &bin_size)) @@ -243,5 +350,30 @@ int main(int argc, char *argv[], char *envp[]) printf("Output: 0x%lx\n", result); + memset(&exception, 0, sizeof(exception)); + + addr = vdso_get_base_addr(envp); + if (!addr) + exit(1); + + if (!vdso_get_symtab(addr, &symtab)) + exit(1); + + eenter_sym = vdso_symtab_get(&symtab, "__vdso_sgx_enter_enclave"); + if (!eenter_sym) + exit(1); + eenter = addr + eenter_sym->st_value; + + printf("Input: 0x%lx\n", MAGIC); + + sgx_call_vdso((void *)&MAGIC, &result, 0, NULL, NULL, NULL, + (void *)secs.base, &exception, NULL); + if (result != MAGIC) { + fprintf(stderr, "0x%lx != 0x%lx\n", result, MAGIC); + exit(1); + } + + printf("Output: 0x%lx\n", result); + exit(0); } diff --git a/tools/testing/selftests/x86/sgx/sgx_call.S b/tools/testing/selftests/x86/sgx/sgx_call.S index ca4c7893f9d9..e71f44f7a995 100644 --- a/tools/testing/selftests/x86/sgx/sgx_call.S +++ b/tools/testing/selftests/x86/sgx/sgx_call.S @@ -21,3 +21,46 @@ sgx_async_exit: ENCLU pop %rbx ret + + .global sgx_call_vdso +sgx_call_vdso: + .cfi_startproc + push %r15 + .cfi_adjust_cfa_offset 8 + .cfi_rel_offset %r15, 0 + push %r14 + .cfi_adjust_cfa_offset 8 + .cfi_rel_offset %r14, 0 + push %r13 + .cfi_adjust_cfa_offset 8 + .cfi_rel_offset %r13, 0 + push %r12 + .cfi_adjust_cfa_offset 8 + .cfi_rel_offset %r12, 0 + push %rbx + .cfi_adjust_cfa_offset 8 + .cfi_rel_offset %rbx, 0 + push $0 + .cfi_adjust_cfa_offset 8 + push 0x48(%rsp) + .cfi_adjust_cfa_offset 8 + push 0x48(%rsp) + .cfi_adjust_cfa_offset 8 + push 0x48(%rsp) + .cfi_adjust_cfa_offset 8 + mov $2, %eax + call *eenter(%rip) + add $0x20, %rsp + .cfi_adjust_cfa_offset -0x20 + pop %rbx + .cfi_adjust_cfa_offset -8 + pop %r12 + .cfi_adjust_cfa_offset -8 + pop %r13 + .cfi_adjust_cfa_offset -8 + pop %r14 + .cfi_adjust_cfa_offset -8 + pop %r15 + .cfi_adjust_cfa_offset -8 + ret + .cfi_endproc diff --git a/tools/testing/selftests/x86/sgx/sgx_call.h b/tools/testing/selftests/x86/sgx/sgx_call.h index bf72068ada23..a4072c5ecce7 100644 --- a/tools/testing/selftests/x86/sgx/sgx_call.h +++ b/tools/testing/selftests/x86/sgx/sgx_call.h @@ -8,4 +8,7 @@ void sgx_call_eenter(void *rdi, void *rsi, void *entry); +int sgx_call_vdso(void *rdi, void *rsi, long rdx, void *rcx, void *r8, void *r9, + void *tcs, struct sgx_enclave_exception *ei, void *cb); + #endif /* SGX_CALL_H */ -- 2.20.1

4 years, 11 months

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[PATCH v25 12/21] selftests/x86: Add a selftest for SGX

by Jarkko Sakkinen

Add a selftest for SGX. It is a trivial test where a simple enclave copies one 64-bit word of memory between two memory locations given to the enclave as arguments. Use ENCLS[EENTER] to invoke the enclave. Cc: linux-sgx(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen(a)linux.intel.com> --- tools/testing/selftests/x86/sgx/.gitignore | 3 + tools/testing/selftests/x86/sgx/Makefile | 48 ++ tools/testing/selftests/x86/sgx/defines.h | 17 + tools/testing/selftests/x86/sgx/encl.c | 20 + tools/testing/selftests/x86/sgx/encl.lds | 34 ++ .../selftests/x86/sgx/encl_bootstrap.S | 94 ++++ tools/testing/selftests/x86/sgx/main.c | 247 +++++++++ tools/testing/selftests/x86/sgx/sgx_call.S | 23 + tools/testing/selftests/x86/sgx/sgx_call.h | 11 + tools/testing/selftests/x86/sgx/sgxsign.c | 493 ++++++++++++++++++ .../testing/selftests/x86/sgx/signing_key.pem | 39 ++ 11 files changed, 1029 insertions(+) create mode 100644 tools/testing/selftests/x86/sgx/.gitignore create mode 100644 tools/testing/selftests/x86/sgx/Makefile create mode 100644 tools/testing/selftests/x86/sgx/defines.h create mode 100644 tools/testing/selftests/x86/sgx/encl.c create mode 100644 tools/testing/selftests/x86/sgx/encl.lds create mode 100644 tools/testing/selftests/x86/sgx/encl_bootstrap.S create mode 100644 tools/testing/selftests/x86/sgx/main.c create mode 100644 tools/testing/selftests/x86/sgx/sgx_call.S create mode 100644 tools/testing/selftests/x86/sgx/sgx_call.h create mode 100644 tools/testing/selftests/x86/sgx/sgxsign.c create mode 100644 tools/testing/selftests/x86/sgx/signing_key.pem diff --git a/tools/testing/selftests/x86/sgx/.gitignore b/tools/testing/selftests/x86/sgx/.gitignore new file mode 100644 index 000000000000..98eb2d439606 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/.gitignore @@ -0,0 +1,3 @@ +encl.ss +sgxsign +test_sgx diff --git a/tools/testing/selftests/x86/sgx/Makefile b/tools/testing/selftests/x86/sgx/Makefile new file mode 100644 index 000000000000..f838700029e2 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/Makefile @@ -0,0 +1,48 @@ +top_srcdir = ../../../../.. + +include ../../lib.mk + +ifndef OBJCOPY +OBJCOPY := $(CROSS_COMPILE)objcopy +endif + +INCLUDES := -I$(top_srcdir)/tools/include +HOST_CFLAGS := -Wall -Werror -g $(INCLUDES) -fPIC -z noexecstack +ENCL_CFLAGS := -Wall -Werror -static -nostdlib -nostartfiles -fPIC \ + -fno-stack-protector -mrdrnd $(INCLUDES) + +TEST_CUSTOM_PROGS := $(OUTPUT)/test_sgx $(OUTPUT)/encl.bin $(OUTPUT)/encl.ss + +all: $(TEST_CUSTOM_PROGS) + +$(OUTPUT)/test_sgx: $(OUTPUT)/main.o $(OUTPUT)/sgx_call.o + $(CC) $(HOST_CFLAGS) -o $@ $^ + +$(OUTPUT)/main.o: main.c + $(CC) $(HOST_CFLAGS) -c $< -o $@ + +$(OUTPUT)/sgx_call.o: sgx_call.S + $(CC) $(HOST_CFLAGS) -c $< -o $@ + +$(OUTPUT)/encl.bin: $(OUTPUT)/encl.elf $(OUTPUT)/sgxsign + $(OBJCOPY) -O binary $< $@ + +$(OUTPUT)/encl.elf: encl.lds encl.c encl_bootstrap.S + $(CC) $(ENCL_CFLAGS) -T $^ -o $@ + +$(OUTPUT)/encl.ss: $(OUTPUT)/encl.bin + $(OUTPUT)/sgxsign signing_key.pem $(OUTPUT)/encl.bin $(OUTPUT)/encl.ss + +$(OUTPUT)/sgxsign: sgxsign.c + $(CC) $(INCLUDES) -o $@ $< -lcrypto + +EXTRA_CLEAN := \ + $(OUTPUT)/encl.bin \ + $(OUTPUT)/encl.elf \ + $(OUTPUT)/encl.ss \ + $(OUTPUT)/sgx_call.o \ + $(OUTPUT)/sgxsign \ + $(OUTPUT)/test_sgx \ + $(OUTPUT)/test_sgx.o \ + +.PHONY: clean diff --git a/tools/testing/selftests/x86/sgx/defines.h b/tools/testing/selftests/x86/sgx/defines.h new file mode 100644 index 000000000000..87264f85cb9f --- /dev/null +++ b/tools/testing/selftests/x86/sgx/defines.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright(c) 2016-19 Intel Corporation. + */ + +#ifndef DEFINES_H +#define DEFINES_H + +#include <stdint.h> + +#define __aligned(x) __attribute__((__aligned__(x))) +#define __packed __attribute__((packed)) + +#include "../../../../../arch/x86/kernel/cpu/sgx/arch.h" +#include "../../../../../arch/x86/include/uapi/asm/sgx.h" + +#endif /* DEFINES_H */ diff --git a/tools/testing/selftests/x86/sgx/encl.c b/tools/testing/selftests/x86/sgx/encl.c new file mode 100644 index 000000000000..ede915399742 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/encl.c @@ -0,0 +1,20 @@ +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) +// Copyright(c) 2016-18 Intel Corporation. + +#include <stddef.h> +#include "defines.h" + +static void *memcpy(void *dest, const void *src, size_t n) +{ + size_t i; + + for (i = 0; i < n; i++) + ((char *)dest)[i] = ((char *)src)[i]; + + return dest; +} + +void encl_body(void *rdi, void *rsi) +{ + memcpy(rsi, rdi, 8); +} diff --git a/tools/testing/selftests/x86/sgx/encl.lds b/tools/testing/selftests/x86/sgx/encl.lds new file mode 100644 index 000000000000..9a56d3064104 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/encl.lds @@ -0,0 +1,34 @@ +OUTPUT_FORMAT(elf64-x86-64) + +SECTIONS +{ + . = 0; + .tcs : { + *(.tcs*) + } + + . = ALIGN(4096); + .text : { + *(.text*) + *(.rodata*) + } + + . = ALIGN(4096); + .data : { + *(.data*) + } + + /DISCARD/ : { + *(.data*) + *(.comment*) + *(.note*) + *(.debug*) + *(.eh_frame*) + } +} + +ASSERT(!DEFINED(.altinstructions), "ALTERNATIVES are not supported in enclaves") +ASSERT(!DEFINED(.altinstr_replacement), "ALTERNATIVES are not supported in enclaves") +ASSERT(!DEFINED(.discard.retpoline_safe), "RETPOLINE ALTERNATIVES are not supported in enclaves") +ASSERT(!DEFINED(.discard.nospec), "RETPOLINE ALTERNATIVES are not supported in enclaves") +ASSERT(!DEFINED(.got.plt), "Libcalls are not supported in enclaves") diff --git a/tools/testing/selftests/x86/sgx/encl_bootstrap.S b/tools/testing/selftests/x86/sgx/encl_bootstrap.S new file mode 100644 index 000000000000..d07f970ccdf9 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/encl_bootstrap.S @@ -0,0 +1,94 @@ +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */ +/* + * Copyright(c) 2016-18 Intel Corporation. + */ + + .macro ENCLU + .byte 0x0f, 0x01, 0xd7 + .endm + + .section ".tcs", "a" + .balign 4096 + + .fill 1, 8, 0 # STATE (set by CPU) + .fill 1, 8, 0 # FLAGS + .quad encl_ssa # OSSA + .fill 1, 4, 0 # CSSA (set by CPU) + .fill 1, 4, 1 # NSSA + .quad encl_entry # OENTRY + .fill 1, 8, 0 # AEP (set by EENTER and ERESUME) + .fill 1, 8, 0 # OFSBASE + .fill 1, 8, 0 # OGSBASE + .fill 1, 4, 0xFFFFFFFF # FSLIMIT + .fill 1, 4, 0xFFFFFFFF # GSLIMIT + .fill 4024, 1, 0 # Reserved + + .text + +encl_entry: + # RBX contains the base address for TCS, which is also the first address + # inside the enclave. By adding the value of le_stack_end to it, we get + # the absolute address for the stack. + lea (encl_stack)(%rbx), %rax + xchg %rsp, %rax + push %rax + + push %rcx # push the address after EENTER + push %rbx # push the enclave base address + + call encl_body + + pop %rbx # pop the enclave base address + + # Restore XSAVE registers to a synthetic state. + mov $0xFFFFFFFF, %rax + mov $0xFFFFFFFF, %rdx + lea (xsave_area)(%rbx), %rdi + fxrstor (%rdi) + + # Clear GPRs. + xor %rcx, %rcx + xor %rdx, %rdx + xor %rdi, %rdi + xor %rsi, %rsi + xor %r8, %r8 + xor %r9, %r9 + xor %r10, %r10 + xor %r11, %r11 + xor %r12, %r12 + xor %r13, %r13 + xor %r14, %r14 + xor %r15, %r15 + + # Reset status flags. + add %rdx, %rdx # OF = SF = AF = CF = 0; ZF = PF = 1 + + # Prepare EEXIT target by popping the address of the instruction after + # EENTER to RBX. + pop %rbx + + # Restore the caller stack. + pop %rax + mov %rax, %rsp + + # EEXIT + mov $4, %rax + enclu + + .section ".data", "aw" + +encl_ssa: + .space 4096 + +xsave_area: + .fill 1, 4, 0x037F # FCW + .fill 5, 4, 0 + .fill 1, 4, 0x1F80 # MXCSR + .fill 1, 4, 0xFFFF # MXCSR_MASK + .fill 123, 4, 0 + .fill 1, 4, 0x80000000 # XCOMP_BV[63] = 1, compaction mode + .fill 12, 4, 0 + + .balign 4096 + .space 8192 +encl_stack: diff --git a/tools/testing/selftests/x86/sgx/main.c b/tools/testing/selftests/x86/sgx/main.c new file mode 100644 index 000000000000..48ed5fdfb3cb --- /dev/null +++ b/tools/testing/selftests/x86/sgx/main.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) +// Copyright(c) 2016-18 Intel Corporation. + +#include <elf.h> +#include <errno.h> +#include <fcntl.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdint.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/ioctl.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/time.h> +#include <sys/types.h> +#include "defines.h" +#include "sgx_call.h" + +#define PAGE_SIZE 4096 + +static const uint64_t MAGIC = 0x1122334455667788ULL; + +static bool encl_create(int dev_fd, unsigned long bin_size, + struct sgx_secs *secs) +{ + struct sgx_enclave_create ioc; + void *area; + int rc; + + memset(secs, 0, sizeof(*secs)); + secs->ssa_frame_size = 1; + secs->attributes = SGX_ATTR_MODE64BIT; + secs->xfrm = 3; + + for (secs->size = 4096; secs->size < bin_size; ) + secs->size <<= 1; + + area = mmap(NULL, secs->size * 2, PROT_NONE, MAP_SHARED, dev_fd, 0); + if (area == MAP_FAILED) { + perror("mmap"); + return false; + } + + secs->base = ((uint64_t)area + secs->size - 1) & ~(secs->size - 1); + + munmap(area, secs->base - (uint64_t)area); + munmap((void *)(secs->base + secs->size), + (uint64_t)area + secs->size - secs->base); + + ioc.src = (unsigned long)secs; + rc = ioctl(dev_fd, SGX_IOC_ENCLAVE_CREATE, &ioc); + if (rc) { + fprintf(stderr, "ECREATE failed rc=%d, err=%d.\n", rc, errno); + munmap((void *)secs->base, secs->size); + return false; + } + + return true; +} + +static bool encl_add_pages(int dev_fd, unsigned long offset, void *data, + unsigned long length, uint64_t flags) +{ + struct sgx_enclave_add_pages ioc; + struct sgx_secinfo secinfo; + int rc; + + memset(&secinfo, 0, sizeof(secinfo)); + secinfo.flags = flags; + + ioc.src = (uint64_t)data; + ioc.offset = offset; + ioc.length = length; + ioc.secinfo = (unsigned long)&secinfo; + ioc.flags = SGX_PAGE_MEASURE; + + rc = ioctl(dev_fd, SGX_IOC_ENCLAVE_ADD_PAGES, &ioc); + if (rc) { + fprintf(stderr, "EADD failed rc=%d.\n", rc); + return false; + } + + if (ioc.count != ioc.length) { + fprintf(stderr, "Partially processed, update the test.\n"); + return false; + } + + return true; +} + +#define SGX_REG_PAGE_FLAGS \ + (SGX_SECINFO_REG | SGX_SECINFO_R | SGX_SECINFO_W | SGX_SECINFO_X) + +static bool encl_build(struct sgx_secs *secs, void *bin, + unsigned long bin_size, struct sgx_sigstruct *sigstruct) +{ + struct sgx_enclave_init ioc; + void *addr; + int dev_fd; + int rc; + + dev_fd = open("/dev/sgx/enclave", O_RDWR); + if (dev_fd < 0) { + fprintf(stderr, "Unable to open /dev/sgx\n"); + return false; + } + + if (!encl_create(dev_fd, bin_size, secs)) + goto out_dev_fd; + + if (!encl_add_pages(dev_fd, 0, bin, PAGE_SIZE, SGX_SECINFO_TCS)) + goto out_dev_fd; + + if (!encl_add_pages(dev_fd, PAGE_SIZE, bin + PAGE_SIZE, + bin_size - PAGE_SIZE, SGX_REG_PAGE_FLAGS)) + goto out_dev_fd; + + ioc.sigstruct = (uint64_t)sigstruct; + rc = ioctl(dev_fd, SGX_IOC_ENCLAVE_INIT, &ioc); + if (rc) { + printf("EINIT failed rc=%d\n", rc); + goto out_map; + } + + addr = mmap((void *)secs->base, PAGE_SIZE, PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_FIXED, dev_fd, 0); + if (addr == MAP_FAILED) { + fprintf(stderr, "mmap() failed on TCS, errno=%d.\n", errno); + return false; + } + + addr = mmap((void *)(secs->base + PAGE_SIZE), bin_size - PAGE_SIZE, + PROT_READ | PROT_WRITE | PROT_EXEC, + MAP_SHARED | MAP_FIXED, dev_fd, 0); + if (addr == MAP_FAILED) { + fprintf(stderr, "mmap() failed, errno=%d.\n", errno); + return false; + } + + close(dev_fd); + return true; +out_map: + munmap((void *)secs->base, secs->size); +out_dev_fd: + close(dev_fd); + return false; +} + +bool get_file_size(const char *path, off_t *bin_size) +{ + struct stat sb; + int ret; + + ret = stat(path, &sb); + if (ret) { + perror("stat"); + return false; + } + + if (!sb.st_size || sb.st_size & 0xfff) { + fprintf(stderr, "Invalid blob size %lu\n", sb.st_size); + return false; + } + + *bin_size = sb.st_size; + return true; +} + +bool encl_data_map(const char *path, void **bin, off_t *bin_size) +{ + int fd; + + fd = open(path, O_RDONLY); + if (fd == -1) { + fprintf(stderr, "open() %s failed, errno=%d.\n", path, errno); + return false; + } + + if (!get_file_size(path, bin_size)) + goto err_out; + + *bin = mmap(NULL, *bin_size, PROT_READ, MAP_PRIVATE, fd, 0); + if (*bin == MAP_FAILED) { + fprintf(stderr, "mmap() %s failed, errno=%d.\n", path, errno); + goto err_out; + } + + close(fd); + return true; + +err_out: + close(fd); + return false; +} + +bool load_sigstruct(const char *path, void *sigstruct) +{ + int fd; + + fd = open(path, O_RDONLY); + if (fd == -1) { + fprintf(stderr, "open() %s failed, errno=%d.\n", path, errno); + return false; + } + + if (read(fd, sigstruct, sizeof(struct sgx_sigstruct)) != + sizeof(struct sgx_sigstruct)) { + fprintf(stderr, "read() %s failed, errno=%d.\n", path, errno); + close(fd); + return false; + } + + close(fd); + return true; +} + +int main(int argc, char *argv[], char *envp[]) +{ + struct sgx_sigstruct sigstruct; + struct sgx_secs secs; + uint64_t result = 0; + off_t bin_size; + void *bin; + + if (!encl_data_map("encl.bin", &bin, &bin_size)) + exit(1); + + if (!load_sigstruct("encl.ss", &sigstruct)) + exit(1); + + if (!encl_build(&secs, bin, bin_size, &sigstruct)) + exit(1); + + printf("Input: 0x%lx\n", MAGIC); + + sgx_call_eenter((void *)&MAGIC, &result, (void *)secs.base); + if (result != MAGIC) { + fprintf(stderr, "0x%lx != 0x%lx\n", result, MAGIC); + exit(1); + } + + printf("Output: 0x%lx\n", result); + + exit(0); +} diff --git a/tools/testing/selftests/x86/sgx/sgx_call.S b/tools/testing/selftests/x86/sgx/sgx_call.S new file mode 100644 index 000000000000..ca4c7893f9d9 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/sgx_call.S @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */ +/** +* Copyright(c) 2016-18 Intel Corporation. +*/ + + .text + + .macro ENCLU + .byte 0x0f, 0x01, 0xd7 + .endm + + .text + + .global sgx_call_eenter +sgx_call_eenter: + push %rbx + mov $0x02, %rax + mov %rdx, %rbx + lea sgx_async_exit(%rip), %rcx +sgx_async_exit: + ENCLU + pop %rbx + ret diff --git a/tools/testing/selftests/x86/sgx/sgx_call.h b/tools/testing/selftests/x86/sgx/sgx_call.h new file mode 100644 index 000000000000..bf72068ada23 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/sgx_call.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright(c) 2016-19 Intel Corporation. + */ + +#ifndef SGX_CALL_H +#define SGX_CALL_H + +void sgx_call_eenter(void *rdi, void *rsi, void *entry); + +#endif /* SGX_CALL_H */ diff --git a/tools/testing/selftests/x86/sgx/sgxsign.c b/tools/testing/selftests/x86/sgx/sgxsign.c new file mode 100644 index 000000000000..3d9007af40c9 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/sgxsign.c @@ -0,0 +1,493 @@ +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) +// Copyright(c) 2016-18 Intel Corporation. + +#define _GNU_SOURCE +#include <getopt.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <unistd.h> +#include <openssl/err.h> +#include <openssl/pem.h> +#include "defines.h" + +struct sgx_sigstruct_payload { + struct sgx_sigstruct_header header; + struct sgx_sigstruct_body body; +}; + +static bool check_crypto_errors(void) +{ + int err; + bool had_errors = false; + const char *filename; + int line; + char str[256]; + + for ( ; ; ) { + if (ERR_peek_error() == 0) + break; + + had_errors = true; + err = ERR_get_error_line(&filename, &line); + ERR_error_string_n(err, str, sizeof(str)); + fprintf(stderr, "crypto: %s: %s:%d\n", str, filename, line); + } + + return had_errors; +} + +static void exit_usage(const char *program) +{ + fprintf(stderr, + "Usage: %s/sign-le <key> <enclave> <sigstruct>\n", program); + exit(1); +} + +static inline const BIGNUM *get_modulus(RSA *key) +{ +#if OPENSSL_VERSION_NUMBER < 0x10100000L + return key->n; +#else + const BIGNUM *n; + + RSA_get0_key(key, &n, NULL, NULL); + return n; +#endif +} + +static RSA *load_sign_key(const char *path) +{ + FILE *f; + RSA *key; + + f = fopen(path, "rb"); + if (!f) { + fprintf(stderr, "Unable to open %s\n", path); + return NULL; + } + key = RSA_new(); + if (!PEM_read_RSAPrivateKey(f, &key, NULL, NULL)) + return NULL; + fclose(f); + + if (BN_num_bytes(get_modulus(key)) != SGX_MODULUS_SIZE) { + fprintf(stderr, "Invalid key size %d\n", + BN_num_bytes(get_modulus(key))); + RSA_free(key); + return NULL; + } + + return key; +} + +static void reverse_bytes(void *data, int length) +{ + int i = 0; + int j = length - 1; + uint8_t temp; + uint8_t *ptr = data; + + while (i < j) { + temp = ptr[i]; + ptr[i] = ptr[j]; + ptr[j] = temp; + i++; + j--; + } +} + +enum mrtags { + MRECREATE = 0x0045544145524345, + MREADD = 0x0000000044444145, + MREEXTEND = 0x00444E4554584545, +}; + +static bool mrenclave_update(EVP_MD_CTX *ctx, const void *data) +{ + if (!EVP_DigestUpdate(ctx, data, 64)) { + fprintf(stderr, "digest update failed\n"); + return false; + } + + return true; +} + +static bool mrenclave_commit(EVP_MD_CTX *ctx, uint8_t *mrenclave) +{ + unsigned int size; + + if (!EVP_DigestFinal_ex(ctx, (unsigned char *)mrenclave, &size)) { + fprintf(stderr, "digest commit failed\n"); + return false; + } + + if (size != 32) { + fprintf(stderr, "invalid digest size = %u\n", size); + return false; + } + + return true; +} + +struct mrecreate { + uint64_t tag; + uint32_t ssaframesize; + uint64_t size; + uint8_t reserved[44]; +} __attribute__((__packed__)); + + +static bool mrenclave_ecreate(EVP_MD_CTX *ctx, uint64_t blob_size) +{ + struct mrecreate mrecreate; + uint64_t encl_size; + + for (encl_size = 0x1000; encl_size < blob_size; ) + encl_size <<= 1; + + memset(&mrecreate, 0, sizeof(mrecreate)); + mrecreate.tag = MRECREATE; + mrecreate.ssaframesize = 1; + mrecreate.size = encl_size; + + if (!EVP_DigestInit_ex(ctx, EVP_sha256(), NULL)) + return false; + + return mrenclave_update(ctx, &mrecreate); +} + +struct mreadd { + uint64_t tag; + uint64_t offset; + uint64_t flags; /* SECINFO flags */ + uint8_t reserved[40]; +} __attribute__((__packed__)); + +static bool mrenclave_eadd(EVP_MD_CTX *ctx, uint64_t offset, uint64_t flags) +{ + struct mreadd mreadd; + + memset(&mreadd, 0, sizeof(mreadd)); + mreadd.tag = MREADD; + mreadd.offset = offset; + mreadd.flags = flags; + + return mrenclave_update(ctx, &mreadd); +} + +struct mreextend { + uint64_t tag; + uint64_t offset; + uint8_t reserved[48]; +} __attribute__((__packed__)); + +static bool mrenclave_eextend(EVP_MD_CTX *ctx, uint64_t offset, uint8_t *data) +{ + struct mreextend mreextend; + int i; + + for (i = 0; i < 0x1000; i += 0x100) { + memset(&mreextend, 0, sizeof(mreextend)); + mreextend.tag = MREEXTEND; + mreextend.offset = offset + i; + + if (!mrenclave_update(ctx, &mreextend)) + return false; + + if (!mrenclave_update(ctx, &data[i + 0x00])) + return false; + + if (!mrenclave_update(ctx, &data[i + 0x40])) + return false; + + if (!mrenclave_update(ctx, &data[i + 0x80])) + return false; + + if (!mrenclave_update(ctx, &data[i + 0xC0])) + return false; + } + + return true; +} + +/** + * measure_encl - measure enclave + * @path: path to the enclave + * @mrenclave: measurement + * + * Calculates MRENCLAVE. Assumes that the very first page is a TCS page and + * following pages are regular pages. Does not measure the contents of the + * enclave as the signing tool is used at the moment only for the launch + * enclave, which is pass-through (everything gets a token). + */ +static bool measure_encl(const char *path, uint8_t *mrenclave) +{ + FILE *file; + struct stat sb; + EVP_MD_CTX *ctx; + uint64_t flags; + uint64_t offset; + uint8_t data[0x1000]; + int rc; + + ctx = EVP_MD_CTX_create(); + if (!ctx) + return false; + + file = fopen(path, "rb"); + if (!file) { + perror("fopen"); + EVP_MD_CTX_destroy(ctx); + return false; + } + + rc = stat(path, &sb); + if (rc) { + perror("stat"); + goto out; + } + + if (!sb.st_size || sb.st_size & 0xfff) { + fprintf(stderr, "Invalid blob size %lu\n", sb.st_size); + goto out; + } + + if (!mrenclave_ecreate(ctx, sb.st_size)) + goto out; + + for (offset = 0; offset < sb.st_size; offset += 0x1000) { + if (!offset) + flags = SGX_SECINFO_TCS; + else + flags = SGX_SECINFO_REG | SGX_SECINFO_R | + SGX_SECINFO_W | SGX_SECINFO_X; + + if (!mrenclave_eadd(ctx, offset, flags)) + goto out; + + rc = fread(data, 1, 0x1000, file); + if (!rc) + break; + if (rc < 0x1000) + goto out; + + if (!mrenclave_eextend(ctx, offset, data)) + goto out; + } + + if (!mrenclave_commit(ctx, mrenclave)) + goto out; + + fclose(file); + EVP_MD_CTX_destroy(ctx); + return true; +out: + fclose(file); + EVP_MD_CTX_destroy(ctx); + return false; +} + +/** + * sign_encl - sign enclave + * @sigstruct: pointer to SIGSTRUCT + * @key: 3072-bit RSA key + * @signature: byte array for the signature + * + * Calculates EMSA-PKCSv1.5 signature for the given SIGSTRUCT. The result is + * stored in big-endian format so that it can be further passed to OpenSSL + * libcrypto functions. + */ +static bool sign_encl(const struct sgx_sigstruct *sigstruct, RSA *key, + uint8_t *signature) +{ + struct sgx_sigstruct_payload payload; + unsigned int siglen; + uint8_t digest[SHA256_DIGEST_LENGTH]; + bool ret; + + memcpy(&payload.header, &sigstruct->header, sizeof(sigstruct->header)); + memcpy(&payload.body, &sigstruct->body, sizeof(sigstruct->body)); + + SHA256((unsigned char *)&payload, sizeof(payload), digest); + + ret = RSA_sign(NID_sha256, digest, SHA256_DIGEST_LENGTH, signature, + &siglen, key); + + return ret; +} + +struct q1q2_ctx { + BN_CTX *bn_ctx; + BIGNUM *m; + BIGNUM *s; + BIGNUM *q1; + BIGNUM *qr; + BIGNUM *q2; +}; + +static void free_q1q2_ctx(struct q1q2_ctx *ctx) +{ + BN_CTX_free(ctx->bn_ctx); + BN_free(ctx->m); + BN_free(ctx->s); + BN_free(ctx->q1); + BN_free(ctx->qr); + BN_free(ctx->q2); +} + +static bool alloc_q1q2_ctx(const uint8_t *s, const uint8_t *m, + struct q1q2_ctx *ctx) +{ + ctx->bn_ctx = BN_CTX_new(); + ctx->s = BN_bin2bn(s, SGX_MODULUS_SIZE, NULL); + ctx->m = BN_bin2bn(m, SGX_MODULUS_SIZE, NULL); + ctx->q1 = BN_new(); + ctx->qr = BN_new(); + ctx->q2 = BN_new(); + + if (!ctx->bn_ctx || !ctx->s || !ctx->m || !ctx->q1 || !ctx->qr || + !ctx->q2) { + free_q1q2_ctx(ctx); + return false; + } + + return true; +} + +static bool calc_q1q2(const uint8_t *s, const uint8_t *m, uint8_t *q1, + uint8_t *q2) +{ + struct q1q2_ctx ctx; + + if (!alloc_q1q2_ctx(s, m, &ctx)) { + fprintf(stderr, "Not enough memory for Q1Q2 calculation\n"); + return false; + } + + if (!BN_mul(ctx.q1, ctx.s, ctx.s, ctx.bn_ctx)) + goto out; + + if (!BN_div(ctx.q1, ctx.qr, ctx.q1, ctx.m, ctx.bn_ctx)) + goto out; + + if (BN_num_bytes(ctx.q1) > SGX_MODULUS_SIZE) { + fprintf(stderr, "Too large Q1 %d bytes\n", + BN_num_bytes(ctx.q1)); + goto out; + } + + if (!BN_mul(ctx.q2, ctx.s, ctx.qr, ctx.bn_ctx)) + goto out; + + if (!BN_div(ctx.q2, NULL, ctx.q2, ctx.m, ctx.bn_ctx)) + goto out; + + if (BN_num_bytes(ctx.q2) > SGX_MODULUS_SIZE) { + fprintf(stderr, "Too large Q2 %d bytes\n", + BN_num_bytes(ctx.q2)); + goto out; + } + + BN_bn2bin(ctx.q1, q1); + BN_bn2bin(ctx.q2, q2); + + free_q1q2_ctx(&ctx); + return true; +out: + free_q1q2_ctx(&ctx); + return false; +} + +static bool save_sigstruct(const struct sgx_sigstruct *sigstruct, + const char *path) +{ + FILE *f = fopen(path, "wb"); + + if (!f) { + fprintf(stderr, "Unable to open %s\n", path); + return false; + } + + fwrite(sigstruct, sizeof(*sigstruct), 1, f); + fclose(f); + return true; +} + +int main(int argc, char **argv) +{ + uint64_t header1[2] = {0x000000E100000006, 0x0000000000010000}; + uint64_t header2[2] = {0x0000006000000101, 0x0000000100000060}; + struct sgx_sigstruct ss; + const char *program; + int opt; + RSA *sign_key; + + memset(&ss, 0, sizeof(ss)); + ss.header.header1[0] = header1[0]; + ss.header.header1[1] = header1[1]; + ss.header.header2[0] = header2[0]; + ss.header.header2[1] = header2[1]; + ss.exponent = 3; + +#ifndef CONFIG_EINITTOKENKEY + ss.body.attributes = SGX_ATTR_MODE64BIT; +#else + ss.body.attributes = SGX_ATTR_MODE64BIT | SGX_ATTR_EINITTOKENKEY; +#endif + ss.body.xfrm = 3, + + program = argv[0]; + + do { + opt = getopt(argc, argv, ""); + switch (opt) { + case -1: + break; + default: + exit_usage(program); + } + } while (opt != -1); + + argc -= optind; + argv += optind; + + if (argc < 3) + exit_usage(program); + + /* sanity check only */ + if (check_crypto_errors()) + exit(1); + + sign_key = load_sign_key(argv[0]); + if (!sign_key) + goto out; + + BN_bn2bin(get_modulus(sign_key), ss.modulus); + + if (!measure_encl(argv[1], ss.body.mrenclave)) + goto out; + + if (!sign_encl(&ss, sign_key, ss.signature)) + goto out; + + if (!calc_q1q2(ss.signature, ss.modulus, ss.q1, ss.q2)) + goto out; + + /* convert to little endian */ + reverse_bytes(ss.signature, SGX_MODULUS_SIZE); + reverse_bytes(ss.modulus, SGX_MODULUS_SIZE); + reverse_bytes(ss.q1, SGX_MODULUS_SIZE); + reverse_bytes(ss.q2, SGX_MODULUS_SIZE); + + if (!save_sigstruct(&ss, argv[2])) + goto out; + exit(0); +out: + check_crypto_errors(); + exit(1); +} diff --git a/tools/testing/selftests/x86/sgx/signing_key.pem b/tools/testing/selftests/x86/sgx/signing_key.pem new file mode 100644 index 000000000000..d76f21f19187 --- /dev/null +++ b/tools/testing/selftests/x86/sgx/signing_key.pem @@ -0,0 +1,39 @@ +-----BEGIN RSA PRIVATE KEY----- +MIIG4wIBAAKCAYEApalGbq7Q+usM91CPtksu3D+b0Prc8gAFL6grM3mg85A5Bx8V +cfMXPgtrw8EYFwQxDAvzZWwl+9VfOX0ECrFRBkOHcOiG0SnADN8+FLj1UiNUQwbp +S6OzhNWuRcSbGraSOyUlVlV0yMQSvewyzGklOaXBe30AJqzIBc8QfdSxKuP8rs0Z +ga6k/Bl73osrYKByILJTUUeZqjLERsE6GebsdzbWgKn8qVqng4ZS4yMNg6LeRlH3 ++9CIPgg4jwpSLHcp7dq2qTIB9a0tGe9ayp+5FbucpB6U7ePold0EeRN6RlJGDF9k +L93v8P5ykz5G5gYZ2g0K1X2sHIWV4huxPgv5PXgdyQYbK+6olqj0d5rjYuwX57Ul +k6SroPS1U6UbdCjG5txM+BNGU0VpD0ZhrIRw0leQdnNcCO9sTJuInZrgYacSVJ7u +mtB+uCt+uzUesc+l+xPRYA+9e14lLkZp7AAmo9FvL816XDI09deehJ3i/LmHKCRN +tuqC5TprRjFwUr6dAgEDAoIBgG5w2Z8fNfycs0+LCnmHdJLVEotR6KFVWMpwHMz7 +wKJgJgS/Y6FMuilc8oKAuroCy11dTO5IGVKOP3uorVx2NgQtBPXwWeDGgAiU1A3Q +o4wXjYIEm4fCd63jyYPYZ2ckYXzDbjmOTdstYdPyzIhGGNEZK6eoqsRzMAPfYFPj +IMdCqHSIu6vJw1K7p+myHOsVoWshjODaZnF3LYSA0WaZ8vokjwBxUxuRxQJZjJds +s60XPtmL+qfgWtQFewoG4XL6GuD8FcXccynRRtzrLtFNPIl9BQfWfjBBhTC1/Te1 +0Z6XbZvpdUTD9OfLB7SbR2OUFNpKQgriO0iYVdbW3cr7uu38Zwp4W1TX73DPjoi6 +KNooP6SGWd4mRJW2+dUmSYS4QNG8eVVZswKcploEIXlAKRsOe4kzJJ1iETugIe85 +uX8nd1WYEp65xwoRUg8hqng0MeyveVbXqNKuJG6tzNDt9kgFYo+hmC/oouAW2Dtc +T9jdRAwKJXqA2Eg6OkgXCEv+kwKBwQDYaQiFMlFhsmLlqI+EzCUh7c941/cL7m6U +7j98+8ngl0HgCEcrc10iJVCKakQW3YbPzAx3XkKTaGjWazvvrFarXIGlOud64B8a +iWyQ7VdlnmZnNEdk+C83tI91OQeaTKqRLDGzKh29Ry/jL8Pcbazt+kDgxa0H7qJp +roADUanLQuNkYubpbhFBh3xpa2EExaVq6rF7nIVsD8W9TrbmPKA4LgH7z0iy544D +kVCNYsTjYDdUWP+WiSor8kCnnpjnN9sCgcEAw/eNezUD1UDf6OYFC9+5JZJFn4Tg +mZMyN93JKIb199ffwnjtHUSjcyiWeesXucpzwtGbTcwQnDisSW4oneYKLSEBlBaq +scqiUugyGZZOthFSCbdXYXMViK2vHrKlkse7GxVlROKcEhM/pRBrmjaGO8eWR+D4 +FO2wCXzVs3KgV6j779frw0vC54oHOxc9+Lu1rSHp4i+600koyvL/zF6U/5tZXIvN +YW2yoiQJnjCmVA1pwbwV6KAUTPDTMnBK+YjnAoHBAJBGBa4hi5Z27JkbCliIGMFJ +NPs6pLKe9GNJf6in2+sPgUAFhMeiPhbDiwbxgrnpBIqICE+ULGJFmzmc0p/IOceT +ARjR76dAFLxbnbXzj5kURETNhO36yiUjCk4mBRGIcbYddndxaSjaH+zKgpLzyJ6m +1esuc1qfFvEfAAI2cTIsl5hB70ZJYNZaUvDyQK3ZGPHxy6e9rkgKg9OJz0QoatAe +q/002yHvtAJg4F5B2JeVejg7VQ8GHB1MKxppu0TP5wKBwQCCpQj8zgKOKz/wmViy +lSYZDC5qWJW7t3bP6TDFr06lOpUsUJ4TgxeiGw778g/RMaKB4RIz3WBoJcgw9BsT +7rFza1ZiucchMcGMmswRDt8kC4wGejpA92Owc8oUdxkMhSdnY5jYlxK2t3/DYEe8 +JFl9L7mFQKVjSSAGUzkiTGrlG1Kf5UfXh9dFBq98uilQfSPIwUaWynyM23CHTKqI +Pw3/vOY9sojrnncWwrEUIG7is5vWfWPwargzSzd29YdRBe8CgcEAuRVewK/YeNOX +B7ZG6gKKsfsvrGtY7FPETzLZAHjoVXYNea4LVZ2kn4hBXXlvw/4HD+YqcTt4wmif +5JQlDvjNobUiKJZpzy7hklVhF7wZFl4pCF7Yh43q9iQ7gKTaeUG7MiaK+G8Zz8aY +HW9rsiihbdZkccMvnPfO9334XMxl3HtBRzLstjUlbLB7Sdh+7tZ3JQidCOFNs5pE +XyWwnASPu4tKfDahH1UUTp1uJcq/6716CSWg080avYxFcn75qqsb +-----END RSA PRIVATE KEY----- -- 2.20.1

4 years, 11 months

1
0
0 0

[PATCH v3 00/12] mm/gup: track FOLL_PIN pages

by John Hubbard

Matthew, I've merged in your dump_page() ideas, and also factored things out into a new __dump_tail_page() routine, in order to save a few indentation levels, mainly. Kirill, thanks for your review comments. I've applied them, and I think splitting this up as you recommended really makes it a lot better, and easier to spot problems. ============================================================ Changes since v2: * Rebased onto linux.git, because the akpm tree for 5.6 has been merged. * Split the tracking patch into even more patches, as requested. * Merged Matthew Wilcox's dump_page() changes into mine, as part of the first patch. * Renamed: page_dma_pinned() --> page_maybe_dma_pinned(), in response to Kirill Shutemov's review. * Moved a WARN to the top of a routine, and fixed a typo in the commit description of patch #7, also as suggested by Kirill. ============================================================ Changes since v1: * Split the tracking patch into 6 smaller patches * Rebased onto today's linux-next/akpm (there weren't any conflicts). * Fixed an "unsigned int" vs. "int" problem in gup_benchmark, reported by Nathan Chancellor. (I don't see it in my local builds, probably because they use gcc, but an LLVM test found the mismatch.) * Fixed a huge page pincount problem (add/subtract vs. increment/decrement), spotted by Jan Kara. ============================================================ There is a reasonable case to be made for merging two of the patches (patches 4 and 5), given that patch 4 provides tracking that has upper limits on the number of pins that can be done with huge pages. Let me know if anyone wants those merged, but unless there is some weird chance of someone grabbing patch 4 and not patch 5, I don't really see the need. Meanwhile, it's easier to review in this form. Also, patch 3 has been revived. Earlier reviewers asked for it to be merged into the tracking patch (one cannot please everyone, heh), but now it's back out on it's own. This activates tracking of FOLL_PIN pages. This is in support of fixing the get_user_pages()+DMA problem described in [1]-[4]. It is based on today's (Jan 28) linux-next (branch: akpm), commit 280e9cb00b41 ("drivers/media/platform/sti/delta/delta-ipc.c: fix read buffer overflow") There is a git repo and branch, for convenience in reviewing: git@github.com:johnhubbard/linux.git track_user_pages_v2_linux-next_akpm_28Jan2020 FOLL_PIN support is (so far) in mmotm and linux-next. However, the patch to use FOLL_PIN to track pages was *not* submitted, because Leon saw an RDMA test suite failure that involved (I think) page refcount overflows when huge pages were used. This patch definitively solves that kind of overflow problem, by adding an exact pincount, for compound pages (of order > 1), in the 3rd struct page of a compound page. If available, that form of pincounting is used, instead of the GUP_PIN_COUNTING_BIAS approach. Thanks again to Jan Kara for that idea. Here's the last reviewed version of the tracking patch (v11): https://lore.kernel.org/r/20191216222537.491123-1-jhubbard@nvidia.com Jan Kara had provided a reviewed-by tag for that, but I've had to remove it (again) here, due to having changed the patch "a little bit", in order to add the feature described above. Other interesting changes: * dump_page(): added one, or two new things to report for compound pages: head refcount (for all compound pages), and map_pincount (for compound pages of order > 1). * Documentation/core-api/pin_user_pages.rst: removed the "TODO" for the huge page refcount upper limit problems, and added notes about how it works now. Also added a note about the dump_page() enhancements. * Added some comments in gup.c and mm.h, to explain that there are two ways to count pinned pages: exact (for compound pages of order > 1) and fuzzy (GUP_PIN_COUNTING_BIAS: for all other pages). ============================================================ General notes about the tracking patch: This is a prerequisite to solving the problem of proper interactions between file-backed pages, and [R]DMA activities, as discussed in [1], [2], [3], [4] and in a remarkable number of email threads since about 2017. :) In contrast to earlier approaches, the page tracking can be incrementally applied to the kernel call sites that, until now, have been simply calling get_user_pages() ("gup"). In other words, opt-in by changing from this: get_user_pages() (sets FOLL_GET) put_page() to this: pin_user_pages() (sets FOLL_PIN) unpin_user_page() ============================================================ Next steps: * Convert more subsystems from get_user_pages() to pin_user_pages(). * Work with Ira and others to connect this all up with file system leases. [1] Some slow progress on get_user_pages() (Apr 2, 2019): https://lwn.net/Articles/784574/ [2] DMA and get_user_pages() (LPC: Dec 12, 2018): https://lwn.net/Articles/774411/ [3] The trouble with get_user_pages() (Apr 30, 2018): https://lwn.net/Articles/753027/ [4] LWN kernel index: get_user_pages() https://lwn.net/Kernel/Index/#Memory_management-get_user_pages John Hubbard (12): mm: dump_page(): better diagnostics for compound pages mm/gup: split get_user_pages_remote() into two routines mm/gup: pass a flags arg to __gup_device_* functions mm: introduce page_ref_sub_return() mm/gup: pass gup flags to two more routines mm/gup: require FOLL_GET for get_user_pages_fast() mm/gup: track FOLL_PIN pages mm/gup: page->hpage_pinned_refcount: exact pin counts for huge pages mm: dump_page(): better diagnostics for huge pinned pages mm/gup: /proc/vmstat: pin_user_pages (FOLL_PIN) reporting mm/gup_benchmark: support pin_user_pages() and related calls selftests/vm: run_vmtests: invoke gup_benchmark with basic FOLL_PIN coverage Documentation/core-api/pin_user_pages.rst | 53 +-- include/linux/mm.h | 108 ++++- include/linux/mm_types.h | 7 +- include/linux/mmzone.h | 2 + include/linux/page_ref.h | 10 + mm/debug.c | 60 ++- mm/gup.c | 459 ++++++++++++++++----- mm/gup_benchmark.c | 71 +++- mm/huge_memory.c | 29 +- mm/hugetlb.c | 44 +- mm/page_alloc.c | 2 + mm/rmap.c | 6 + mm/vmstat.c | 2 + tools/testing/selftests/vm/gup_benchmark.c | 15 +- tools/testing/selftests/vm/run_vmtests | 22 + 15 files changed, 715 insertions(+), 175 deletions(-) -- 2.25.0

4 years, 11 months

3
42
0 0

[PATCH v10 1/8] hugetlb_cgroup: Add hugetlb_cgroup reservation counter

by Mina Almasry

These counters will track hugetlb reservations rather than hugetlb memory faulted in. This patch only adds the counter, following patches add the charging and uncharging of the counter. This is patch 1 of an 8 patch series. Problem: Currently tasks attempting to reserve more hugetlb memory than is available get a failure at mmap/shmget time. This is thanks to Hugetlbfs Reservations [1]. However, if a task attempts to reserve hugetlb memory only more than its hugetlb_cgroup limit allows, the kernel will allow the mmap/shmget call, but will SIGBUS the task when it attempts to fault the memory in. We have users hitting their hugetlb_cgroup limits and thus we've been looking at this failure mode. We'd like to improve this behavior such that users violating the hugetlb_cgroup limits get an error on mmap/shmget time, rather than getting SIGBUS'd when they try to fault the excess memory in. This gives the user an opportunity to fallback more gracefully to non-hugetlbfs memory for example. The underlying problem is that today's hugetlb_cgroup accounting happens at hugetlb memory *fault* time, rather than at *reservation* time. Thus, enforcing the hugetlb_cgroup limit only happens at fault time, and the offending task gets SIGBUS'd. Proposed Solution: A new page counter named 'hugetlb.xMB.reservation_[limit|usage|max_usage]_in_bytes'. This counter has slightly different semantics than 'hugetlb.xMB.[limit|usage|max_usage]_in_bytes': - While usage_in_bytes tracks all *faulted* hugetlb memory, reservation_usage_in_bytes tracks all *reserved* hugetlb memory and hugetlb memory faulted in without a prior reservation. - If a task attempts to reserve more memory than limit_in_bytes allows, the kernel will allow it to do so. But if a task attempts to reserve more memory than reservation_limit_in_bytes, the kernel will fail this reservation. This proposal is implemented in this patch series, with tests to verify functionality and show the usage. Alternatives considered: 1. A new cgroup, instead of only a new page_counter attached to the existing hugetlb_cgroup. Adding a new cgroup seemed like a lot of code duplication with hugetlb_cgroup. Keeping hugetlb related page counters under hugetlb_cgroup seemed cleaner as well. 2. Instead of adding a new counter, we considered adding a sysctl that modifies the behavior of hugetlb.xMB.[limit|usage]_in_bytes, to do accounting at reservation time rather than fault time. Adding a new page_counter seems better as userspace could, if it wants, choose to enforce different cgroups differently: one via limit_in_bytes, and another via reservation_limit_in_bytes. This could be very useful if you're transitioning how hugetlb memory is partitioned on your system one cgroup at a time, for example. Also, someone may find usage for both limit_in_bytes and reservation_limit_in_bytes concurrently, and this approach gives them the option to do so. Testing: - Added tests passing. - Used libhugetlbfs for regression testing. [1]: https://www.kernel.org/doc/html/latest/vm/hugetlbfs_reserv.html Signed-off-by: Mina Almasry <almasrymina(a)google.com> --- Changes in v10: - Renamed reservation_* to resv.* --- include/linux/hugetlb.h | 4 +- mm/hugetlb_cgroup.c | 115 +++++++++++++++++++++++++++++++++++----- 2 files changed, 104 insertions(+), 15 deletions(-) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 1e897e4168ac1..dea6143aa0685 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -432,8 +432,8 @@ struct hstate { unsigned int surplus_huge_pages_node[MAX_NUMNODES]; #ifdef CONFIG_CGROUP_HUGETLB /* cgroup control files */ - struct cftype cgroup_files_dfl[5]; - struct cftype cgroup_files_legacy[5]; + struct cftype cgroup_files_dfl[7]; + struct cftype cgroup_files_legacy[9]; #endif char name[HSTATE_NAME_LEN]; }; diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index e434b05416c68..209f9b9604d34 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -36,6 +36,11 @@ struct hugetlb_cgroup { */ struct page_counter hugepage[HUGE_MAX_HSTATE]; + /* + * the counter to account for hugepage reservations from hugetlb. + */ + struct page_counter reserved_hugepage[HUGE_MAX_HSTATE]; + atomic_long_t events[HUGE_MAX_HSTATE][HUGETLB_NR_MEMORY_EVENTS]; atomic_long_t events_local[HUGE_MAX_HSTATE][HUGETLB_NR_MEMORY_EVENTS]; @@ -55,6 +60,14 @@ struct hugetlb_cgroup { static struct hugetlb_cgroup *root_h_cgroup __read_mostly; +static inline struct page_counter * +hugetlb_cgroup_get_counter(struct hugetlb_cgroup *h_cg, int idx, bool reserved) +{ + if (reserved) + return &h_cg->reserved_hugepage[idx]; + return &h_cg->hugepage[idx]; +} + static inline struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s) { @@ -295,28 +308,42 @@ void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, enum { RES_USAGE, + RES_RESERVATION_USAGE, RES_LIMIT, + RES_RESERVATION_LIMIT, RES_MAX_USAGE, + RES_RESERVATION_MAX_USAGE, RES_FAILCNT, + RES_RESERVATION_FAILCNT, }; static u64 hugetlb_cgroup_read_u64(struct cgroup_subsys_state *css, struct cftype *cft) { struct page_counter *counter; + struct page_counter *reserved_counter; struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css); counter = &h_cg->hugepage[MEMFILE_IDX(cft->private)]; + reserved_counter = &h_cg->reserved_hugepage[MEMFILE_IDX(cft->private)]; switch (MEMFILE_ATTR(cft->private)) { case RES_USAGE: return (u64)page_counter_read(counter) * PAGE_SIZE; + case RES_RESERVATION_USAGE: + return (u64)page_counter_read(reserved_counter) * PAGE_SIZE; case RES_LIMIT: return (u64)counter->max * PAGE_SIZE; + case RES_RESERVATION_LIMIT: + return (u64)reserved_counter->max * PAGE_SIZE; case RES_MAX_USAGE: return (u64)counter->watermark * PAGE_SIZE; + case RES_RESERVATION_MAX_USAGE: + return (u64)reserved_counter->watermark * PAGE_SIZE; case RES_FAILCNT: return counter->failcnt; + case RES_RESERVATION_FAILCNT: + return reserved_counter->failcnt; default: BUG(); } @@ -338,10 +365,16 @@ static int hugetlb_cgroup_read_u64_max(struct seq_file *seq, void *v) 1 << huge_page_order(&hstates[idx])); switch (MEMFILE_ATTR(cft->private)) { + case RES_RESERVATION_USAGE: + counter = &h_cg->reserved_hugepage[idx]; + /* Fall through. */ case RES_USAGE: val = (u64)page_counter_read(counter); seq_printf(seq, "%llu\n", val * PAGE_SIZE); break; + case RES_RESERVATION_LIMIT: + counter = &h_cg->reserved_hugepage[idx]; + /* Fall through. */ case RES_LIMIT: val = (u64)counter->max; if (val == limit) @@ -365,6 +398,7 @@ static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of, int ret, idx; unsigned long nr_pages; struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of)); + bool reserved = false; if (hugetlb_cgroup_is_root(h_cg)) /* Can't set limit on root */ return -EINVAL; @@ -378,9 +412,14 @@ static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of, nr_pages = round_down(nr_pages, 1 << huge_page_order(&hstates[idx])); switch (MEMFILE_ATTR(of_cft(of)->private)) { + case RES_RESERVATION_LIMIT: + reserved = true; + /* Fall through. */ case RES_LIMIT: mutex_lock(&hugetlb_limit_mutex); - ret = page_counter_set_max(&h_cg->hugepage[idx], nr_pages); + ret = page_counter_set_max(hugetlb_cgroup_get_counter(h_cg, idx, + reserved), + nr_pages); mutex_unlock(&hugetlb_limit_mutex); break; default: @@ -406,18 +445,26 @@ static ssize_t hugetlb_cgroup_reset(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { int ret = 0; - struct page_counter *counter; + struct page_counter *counter, *reserved_counter; struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of)); counter = &h_cg->hugepage[MEMFILE_IDX(of_cft(of)->private)]; + reserved_counter = + &h_cg->reserved_hugepage[MEMFILE_IDX(of_cft(of)->private)]; switch (MEMFILE_ATTR(of_cft(of)->private)) { case RES_MAX_USAGE: page_counter_reset_watermark(counter); break; + case RES_RESERVATION_MAX_USAGE: + page_counter_reset_watermark(reserved_counter); + break; case RES_FAILCNT: counter->failcnt = 0; break; + case RES_RESERVATION_FAILCNT: + reserved_counter->failcnt = 0; + break; default: ret = -EINVAL; break; @@ -472,7 +519,7 @@ static void __init __hugetlb_cgroup_file_dfl_init(int idx) struct hstate *h = &hstates[idx]; /* format the size */ - mem_fmt(buf, 32, huge_page_size(h)); + mem_fmt(buf, sizeof(buf), huge_page_size(h)); /* Add the limit file */ cft = &h->cgroup_files_dfl[0]; @@ -482,15 +529,30 @@ static void __init __hugetlb_cgroup_file_dfl_init(int idx) cft->write = hugetlb_cgroup_write_dfl; cft->flags = CFTYPE_NOT_ON_ROOT; - /* Add the current usage file */ + /* Add the reservation limit file */ cft = &h->cgroup_files_dfl[1]; + snprintf(cft->name, MAX_CFTYPE_NAME, "%s.resv.max", buf); + cft->private = MEMFILE_PRIVATE(idx, RES_RESERVATION_LIMIT); + cft->seq_show = hugetlb_cgroup_read_u64_max; + cft->write = hugetlb_cgroup_write_dfl; + cft->flags = CFTYPE_NOT_ON_ROOT; + + /* Add the current usage file */ + cft = &h->cgroup_files_dfl[2]; snprintf(cft->name, MAX_CFTYPE_NAME, "%s.current", buf); cft->private = MEMFILE_PRIVATE(idx, RES_USAGE); cft->seq_show = hugetlb_cgroup_read_u64_max; cft->flags = CFTYPE_NOT_ON_ROOT; + /* Add the current reservation usage file */ + cft = &h->cgroup_files_dfl[3]; + snprintf(cft->name, MAX_CFTYPE_NAME, "%s.resv.current", buf); + cft->private = MEMFILE_PRIVATE(idx, RES_RESERVATION_USAGE); + cft->seq_show = hugetlb_cgroup_read_u64_max; + cft->flags = CFTYPE_NOT_ON_ROOT; + /* Add the events file */ - cft = &h->cgroup_files_dfl[2]; + cft = &h->cgroup_files_dfl[4]; snprintf(cft->name, MAX_CFTYPE_NAME, "%s.events", buf); cft->private = MEMFILE_PRIVATE(idx, 0); cft->seq_show = hugetlb_events_show; @@ -498,7 +560,7 @@ static void __init __hugetlb_cgroup_file_dfl_init(int idx) cft->flags = CFTYPE_NOT_ON_ROOT; /* Add the events.local file */ - cft = &h->cgroup_files_dfl[3]; + cft = &h->cgroup_files_dfl[5]; snprintf(cft->name, MAX_CFTYPE_NAME, "%s.events.local", buf); cft->private = MEMFILE_PRIVATE(idx, 0); cft->seq_show = hugetlb_events_local_show; @@ -507,7 +569,7 @@ static void __init __hugetlb_cgroup_file_dfl_init(int idx) cft->flags = CFTYPE_NOT_ON_ROOT; /* NULL terminate the last cft */ - cft = &h->cgroup_files_dfl[4]; + cft = &h->cgroup_files_dfl[6]; memset(cft, 0, sizeof(*cft)); WARN_ON(cgroup_add_dfl_cftypes(&hugetlb_cgrp_subsys, @@ -521,7 +583,7 @@ static void __init __hugetlb_cgroup_file_legacy_init(int idx) struct hstate *h = &hstates[idx]; /* format the size */ - mem_fmt(buf, 32, huge_page_size(h)); + mem_fmt(buf, sizeof(buf), huge_page_size(h)); /* Add the limit file */ cft = &h->cgroup_files_legacy[0]; @@ -530,28 +592,55 @@ static void __init __hugetlb_cgroup_file_legacy_init(int idx) cft->read_u64 = hugetlb_cgroup_read_u64; cft->write = hugetlb_cgroup_write_legacy; - /* Add the usage file */ + /* Add the reservation limit file */ cft = &h->cgroup_files_legacy[1]; + snprintf(cft->name, MAX_CFTYPE_NAME, "%s.resv.limit_in_bytes", buf); + cft->private = MEMFILE_PRIVATE(idx, RES_RESERVATION_LIMIT); + cft->read_u64 = hugetlb_cgroup_read_u64; + cft->write = hugetlb_cgroup_write_legacy; + + /* Add the usage file */ + cft = &h->cgroup_files_legacy[2]; snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf); cft->private = MEMFILE_PRIVATE(idx, RES_USAGE); cft->read_u64 = hugetlb_cgroup_read_u64; + /* Add the reservation usage file */ + cft = &h->cgroup_files_legacy[3]; + snprintf(cft->name, MAX_CFTYPE_NAME, "%s.resv.usage_in_bytes", buf); + cft->private = MEMFILE_PRIVATE(idx, RES_RESERVATION_USAGE); + cft->read_u64 = hugetlb_cgroup_read_u64; + /* Add the MAX usage file */ - cft = &h->cgroup_files_legacy[2]; + cft = &h->cgroup_files_legacy[4]; snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf); cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE); cft->write = hugetlb_cgroup_reset; cft->read_u64 = hugetlb_cgroup_read_u64; + /* Add the MAX reservation usage file */ + cft = &h->cgroup_files_legacy[5]; + snprintf(cft->name, MAX_CFTYPE_NAME, "%s.resv.max_usage_in_bytes", buf); + cft->private = MEMFILE_PRIVATE(idx, RES_RESERVATION_MAX_USAGE); + cft->write = hugetlb_cgroup_reset; + cft->read_u64 = hugetlb_cgroup_read_u64; + /* Add the failcntfile */ - cft = &h->cgroup_files_legacy[3]; + cft = &h->cgroup_files_legacy[6]; snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf); - cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT); + cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT); + cft->write = hugetlb_cgroup_reset; + cft->read_u64 = hugetlb_cgroup_read_u64; + + /* Add the reservation failcntfile */ + cft = &h->cgroup_files_legacy[7]; + snprintf(cft->name, MAX_CFTYPE_NAME, "%s.resv.failcnt", buf); + cft->private = MEMFILE_PRIVATE(idx, RES_RESERVATION_FAILCNT); cft->write = hugetlb_cgroup_reset; cft->read_u64 = hugetlb_cgroup_read_u64; /* NULL terminate the last cft */ - cft = &h->cgroup_files_legacy[4]; + cft = &h->cgroup_files_legacy[8]; memset(cft, 0, sizeof(*cft)); WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys, -- 2.25.0.rc1.283.g88dfdc4193-goog

4 years, 11 months

4
23
0 0

[PATCH 0/3] Fix reconnection latency caused by FIN/ACK handling race

by sjpark＠amazon.com

From: SeongJae Park <sjpark(a)amazon.de> When closing a connection, the two acks that required to change closing socket's status to FIN_WAIT_2 and then TIME_WAIT could be processed in reverse order. This is possible in RSS disabled environments such as a connection inside a host. For example, expected state transitions and required packets for the disconnection will be similar to below flow. 00 (Process A) (Process B) 01 ESTABLISHED ESTABLISHED 02 close() 03 FIN_WAIT_1 04 ---FIN--> 05 CLOSE_WAIT 06 <--ACK--- 07 FIN_WAIT_2 08 <--FIN/ACK--- 09 TIME_WAIT 10 ---ACK--> 11 LAST_ACK 12 CLOSED CLOSED The acks in lines 6 and 8 are the acks. If the line 8 packet is processed before the line 6 packet, it will be just ignored as it is not a expected packet, and the later process of the line 6 packet will change the status of Process A to FIN_WAIT_2, but as it has already handled line 8 packet, it will not go to TIME_WAIT and thus will not send the line 10 packet to Process B. Thus, Process B will left in CLOSE_WAIT status, as below. 00 (Process A) (Process B) 01 ESTABLISHED ESTABLISHED 02 close() 03 FIN_WAIT_1 04 ---FIN--> 05 CLOSE_WAIT 06 (<--ACK---) 07 (<--FIN/ACK---) 08 (fired in right order) 09 <--FIN/ACK--- 10 <--ACK--- 11 (processed in reverse order) 12 FIN_WAIT_2 Later, if the Process B sends SYN to Process A for reconnection using the same port, Process A will responds with an ACK for the last flow, which has no increased sequence number. Thus, Process A will send RST, wait for TIMEOUT_INIT (one second in default), and then try reconnection. If reconnections are frequent, the one second latency spikes can be a big problem. Below is a tcpdump results of the problem: 14.436259 IP 127.0.0.1.45150 > 127.0.0.1.4242: Flags [S], seq 2560603644 14.436266 IP 127.0.0.1.4242 > 127.0.0.1.45150: Flags [.], ack 5, win 512 14.436271 IP 127.0.0.1.45150 > 127.0.0.1.4242: Flags [R], seq 2541101298 /* ONE SECOND DELAY */ 15.464613 IP 127.0.0.1.45150 > 127.0.0.1.4242: Flags [S], seq 2560603644 Patchset Organization --------------------- The first patch fix a trivial nit. The second one fix the problem by adjusting the resend delay of the SYN in the case. Finally, the third patch adds a user space test to reproduce this problem. The patches are based on the v5.5. You can also clone the complete git tree: $ git clone git://github.com/sjp38/linux -b patches/finack_lat/v1 The web is also available: https://github.com/sjp38/linux/tree/patches/finack_lat/v1 SeongJae Park (3): net/ipv4/inet_timewait_sock: Fix inconsistent comments tcp: Reduce SYN resend delay if a suspicous ACK is received selftests: net: Add FIN_ACK processing order related latency spike test net/ipv4/inet_timewait_sock.c | 1 + net/ipv4/tcp_input.c | 6 +- tools/testing/selftests/net/.gitignore | 2 + tools/testing/selftests/net/Makefile | 2 + tools/testing/selftests/net/fin_ack_lat.sh | 42 ++++++++++ .../selftests/net/fin_ack_lat_accept.c | 49 +++++++++++ .../selftests/net/fin_ack_lat_connect.c | 81 +++++++++++++++++++ 7 files changed, 182 insertions(+), 1 deletion(-) create mode 100755 tools/testing/selftests/net/fin_ack_lat.sh create mode 100644 tools/testing/selftests/net/fin_ack_lat_accept.c create mode 100644 tools/testing/selftests/net/fin_ack_lat_connect.c -- 2.17.1

4 years, 11 months

6
24
0 0

[PATCH v3 0/2] Fix reconnection latency caused by FIN/ACK handling race

by sj38.park＠gmail.com

From: SeongJae Park <sjpark(a)amazon.de> When closing a connection, the two acks that required to change closing socket's status to FIN_WAIT_2 and then TIME_WAIT could be processed in reverse order. This is possible in RSS disabled environments such as a connection inside a host. For example, expected state transitions and required packets for the disconnection will be similar to below flow. 00 (Process A) (Process B) 01 ESTABLISHED ESTABLISHED 02 close() 03 FIN_WAIT_1 04 ---FIN--> 05 CLOSE_WAIT 06 <--ACK--- 07 FIN_WAIT_2 08 <--FIN/ACK--- 09 TIME_WAIT 10 ---ACK--> 11 LAST_ACK 12 CLOSED CLOSED In some cases such as LINGER option applied socket, the FIN and FIN/ACK will be substituted to RST and RST/ACK, but there is no difference in the main logic. The acks in lines 6 and 8 are the acks. If the line 8 packet is processed before the line 6 packet, it will be just ignored as it is not a expected packet, and the later process of the line 6 packet will change the status of Process A to FIN_WAIT_2, but as it has already handled line 8 packet, it will not go to TIME_WAIT and thus will not send the line 10 packet to Process B. Thus, Process B will left in CLOSE_WAIT status, as below. 00 (Process A) (Process B) 01 ESTABLISHED ESTABLISHED 02 close() 03 FIN_WAIT_1 04 ---FIN--> 05 CLOSE_WAIT 06 (<--ACK---) 07 (<--FIN/ACK---) 08 (fired in right order) 09 <--FIN/ACK--- 10 <--ACK--- 11 (processed in reverse order) 12 FIN_WAIT_2 Later, if the Process B sends SYN to Process A for reconnection using the same port, Process A will responds with an ACK for the last flow, which has no increased sequence number. Thus, Process A will send RST, wait for TIMEOUT_INIT (one second in default), and then try reconnection. If reconnections are frequent, the one second latency spikes can be a big problem. Below is a tcpdump results of the problem: 14.436259 IP 127.0.0.1.45150 > 127.0.0.1.4242: Flags [S], seq 2560603644 14.436266 IP 127.0.0.1.4242 > 127.0.0.1.45150: Flags [.], ack 5, win 512 14.436271 IP 127.0.0.1.45150 > 127.0.0.1.4242: Flags [R], seq 2541101298 /* ONE SECOND DELAY */ 15.464613 IP 127.0.0.1.45150 > 127.0.0.1.4242: Flags [S], seq 2560603644 Patchset Organization --------------------- The first patch fixes the problem by adjusting the first resend delay of the SYN in the case. The second one adds a user space test to reproduce this problem. The patches are based on the v5.5. You can also clone the complete git tree: $ git clone git://github.com/sjp38/linux -b patches/finack_lat/v3 The web is also available: https://github.com/sjp38/linux/tree/patches/finack_lat/v3 Patchset History ---------------- >From v2 (https://lore.kernel.org/linux-kselftest/20200201071859.4231-1-sj38.park@gma…) - Use TCP_TIMEOUT_MIN as reduced delay (Neal Cardwall) - Add Reviewed-by and Signed-off-by from Eric Dumazet >From v1 (https://lore.kernel.org/linux-kselftest/20200131122421.23286-1-sjpark@amazo…) - Drop the trivial comment fix patch (Eric Dumazet) - Limit the delay adjustment to only the first SYN resend (Eric Dumazet) - selftest: Avoid use of hard-coded port number (Eric Dumazet) - Explain RST/ACK and FIN/ACK has no big difference (Neal Cardwell) SeongJae Park (2): tcp: Reduce SYN resend delay if a suspicous ACK is received selftests: net: Add FIN_ACK processing order related latency spike test net/ipv4/tcp_input.c | 8 +- tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/Makefile | 2 + tools/testing/selftests/net/fin_ack_lat.c | 151 +++++++++++++++++++++ tools/testing/selftests/net/fin_ack_lat.sh | 35 +++++ 5 files changed, 196 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/net/fin_ack_lat.c create mode 100755 tools/testing/selftests/net/fin_ack_lat.sh -- 2.17.1

4 years, 11 months

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[PATCH v2 0/2] Fix reconnection latency caused by FIN/ACK handling race

by sj38.park＠gmail.com

From: SeongJae Park <sjpark(a)amazon.de> When closing a connection, the two acks that required to change closing socket's status to FIN_WAIT_2 and then TIME_WAIT could be processed in reverse order. This is possible in RSS disabled environments such as a connection inside a host. For example, expected state transitions and required packets for the disconnection will be similar to below flow. 00 (Process A) (Process B) 01 ESTABLISHED ESTABLISHED 02 close() 03 FIN_WAIT_1 04 ---FIN--> 05 CLOSE_WAIT 06 <--ACK--- 07 FIN_WAIT_2 08 <--FIN/ACK--- 09 TIME_WAIT 10 ---ACK--> 11 LAST_ACK 12 CLOSED CLOSED In some cases such as LINGER option applied socket, the FIN and FIN/ACK will be substituted to RST and RST/ACK, but there is no difference in the main logic. The acks in lines 6 and 8 are the acks. If the line 8 packet is processed before the line 6 packet, it will be just ignored as it is not a expected packet, and the later process of the line 6 packet will change the status of Process A to FIN_WAIT_2, but as it has already handled line 8 packet, it will not go to TIME_WAIT and thus will not send the line 10 packet to Process B. Thus, Process B will left in CLOSE_WAIT status, as below. 00 (Process A) (Process B) 01 ESTABLISHED ESTABLISHED 02 close() 03 FIN_WAIT_1 04 ---FIN--> 05 CLOSE_WAIT 06 (<--ACK---) 07 (<--FIN/ACK---) 08 (fired in right order) 09 <--FIN/ACK--- 10 <--ACK--- 11 (processed in reverse order) 12 FIN_WAIT_2 Later, if the Process B sends SYN to Process A for reconnection using the same port, Process A will responds with an ACK for the last flow, which has no increased sequence number. Thus, Process A will send RST, wait for TIMEOUT_INIT (one second in default), and then try reconnection. If reconnections are frequent, the one second latency spikes can be a big problem. Below is a tcpdump results of the problem: 14.436259 IP 127.0.0.1.45150 > 127.0.0.1.4242: Flags [S], seq 2560603644 14.436266 IP 127.0.0.1.4242 > 127.0.0.1.45150: Flags [.], ack 5, win 512 14.436271 IP 127.0.0.1.45150 > 127.0.0.1.4242: Flags [R], seq 2541101298 /* ONE SECOND DELAY */ 15.464613 IP 127.0.0.1.45150 > 127.0.0.1.4242: Flags [S], seq 2560603644 Patchset Organization --------------------- The first patch fixes the problem by adjusting the first resend delay of the SYN in the case. The second one adds a user space test to reproduce this problem. The patches are based on the v5.5. You can also clone the complete git tree: $ git clone git://github.com/sjp38/linux -b patches/finack_lat/v2 The web is also available: https://github.com/sjp38/linux/tree/patches/finack_lat/v2 Patchset History ---------------- >From v1 (https://lore.kernel.org/linux-kselftest/20200131122421.23286-1-sjpark@amazo…) - Drop the trivial comment fix patch (Eric Dumazet) - Limit the delay adjustment to only the first SYN resend (Eric Dumazet) - selftest: Avoid use of hard-coded port number (Eric Dumazet) - Explain RST/ACK and FIN/ACK has no big difference (Neal Cardwell) SeongJae Park (2): tcp: Reduce SYN resend delay if a suspicous ACK is received selftests: net: Add FIN_ACK processing order related latency spike test net/ipv4/tcp_input.c | 8 +- tools/testing/selftests/net/.gitignore | 2 + tools/testing/selftests/net/Makefile | 2 + tools/testing/selftests/net/fin_ack_lat.c | 151 +++++++++++++++++++++ tools/testing/selftests/net/fin_ack_lat.sh | 35 +++++ 5 files changed, 197 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/net/fin_ack_lat.c create mode 100755 tools/testing/selftests/net/fin_ack_lat.sh -- 2.17.1

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