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[PATCH v13 0/5] Implement IOCTL to get and optionally clear info about PTEs

by Muhammad Usama Anjum

*Changes in v13* - Rebase on top of next-20230414 - Give-up on using uffd_wp_range() and write new helpers, flush tlb only once *Changes in v12* - Update and other memory types to UFFD_FEATURE_WP_ASYNC - Rebaase on top of next-20230406 - Review updates *Changes in v11* - Rebase on top of next-20230307 - Base patches on UFFD_FEATURE_WP_UNPOPULATED - Do a lot of cosmetic changes and review updates - Remove ENGAGE_WP + !GET operation as it can be performed with UFFDIO_WRITEPROTECT *Changes in v10* - Add specific condition to return error if hugetlb is used with wp async - Move changes in tools/include/uapi/linux/fs.h to separate patch - Add documentation *Changes in v9:* - Correct fault resolution for userfaultfd wp async - Fix build warnings and errors which were happening on some configs - Simplify pagemap ioctl's code *Changes in v8:* - Update uffd async wp implementation - Improve PAGEMAP_IOCTL implementation *Changes in v7:* - Add uffd wp async - Update the IOCTL to use uffd under the hood instead of soft-dirty flags *Motivation* The real motivation for adding PAGEMAP_SCAN IOCTL is to emulate Windows GetWriteWatch() syscall [1]. The GetWriteWatch{} retrieves the addresses of the pages that are written to in a region of virtual memory. This syscall is used in Windows applications and games etc. This syscall is being emulated in pretty slow manner in userspace. Our purpose is to enhance the kernel such that we translate it efficiently in a better way. Currently some out of tree hack patches are being used to efficiently emulate it in some kernels. We intend to replace those with these patches. So the whole gaming on Linux can effectively get benefit from this. It means there would be tons of users of this code. CRIU use case [2] was mentioned by Andrei and Danylo: > Use cases for migrating sparse VMAs are binaries sanitized with ASAN, > MSAN or TSAN [3]. All of these sanitizers produce sparse mappings of > shadow memory [4]. Being able to migrate such binaries allows to highly > reduce the amount of work needed to identify and fix post-migration > crashes, which happen constantly. Andrei's defines the following uses of this code: * it is more granular and allows us to track changed pages more effectively. The current interface can clear dirty bits for the entire process only. In addition, reading info about pages is a separate operation. It means we must freeze the process to read information about all its pages, reset dirty bits, only then we can start dumping pages. The information about pages becomes more and more outdated, while we are processing pages. The new interface solves both these downsides. First, it allows us to read pte bits and clear the soft-dirty bit atomically. It means that CRIU will not need to freeze processes to pre-dump their memory. Second, it clears soft-dirty bits for a specified region of memory. It means CRIU will have actual info about pages to the moment of dumping them. * The new interface has to be much faster because basic page filtering is happening in the kernel. With the old interface, we have to read pagemap for each page. *Implementation Evolution (Short Summary)* From the definition of GetWriteWatch(), we feel like kernel's soft-dirty feature can be used under the hood with some additions like: * reset soft-dirty flag for only a specific region of memory instead of clearing the flag for the entire process * get and clear soft-dirty flag for a specific region atomically So we decided to use ioctl on pagemap file to read or/and reset soft-dirty flag. But using soft-dirty flag, sometimes we get extra pages which weren't even written. They had become soft-dirty because of VMA merging and VM_SOFTDIRTY flag. This breaks the definition of GetWriteWatch(). We were able to by-pass this short coming by ignoring VM_SOFTDIRTY until David reported that mprotect etc messes up the soft-dirty flag while ignoring VM_SOFTDIRTY [5]. This wasn't happening until [6] got introduced. We discussed if we can revert these patches. But we could not reach to any conclusion. So at this point, I made couple of tries to solve this whole VM_SOFTDIRTY issue by correcting the soft-dirty implementation: * [7] Correct the bug fixed wrongly back in 2014. It had potential to cause regression. We left it behind. * [8] Keep a list of soft-dirty part of a VMA across splits and merges. I got the reply don't increase the size of the VMA by 8 bytes. At this point, we left soft-dirty considering it is too much delicate and userfaultfd [9] seemed like the only way forward. From there onward, we have been basing soft-dirty emulation on userfaultfd wp feature where kernel resolves the faults itself when WP_ASYNC feature is used. It was straight forward to add WP_ASYNC feature in userfautlfd. Now we get only those pages dirty or written-to which are really written in reality. (PS There is another WP_UNPOPULATED userfautfd feature is required which is needed to avoid pre-faulting memory before write-protecting [9].) All the different masks were added on the request of CRIU devs to create interface more generic and better. [1] https://learn.microsoft.com/en-us/windows/win32/api/memoryapi/nf-memoryapi-… [2] https://lore.kernel.org/all/20221014134802.1361436-1-mdanylo@google.com [3] https://github.com/google/sanitizers [4] https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm#64-bit [5] https://lore.kernel.org/all/bfcae708-db21-04b4-0bbe-712badd03071@redhat.com [6] https://lore.kernel.org/all/20220725142048.30450-1-peterx@redhat.com/ [7] https://lore.kernel.org/all/20221122115007.2787017-1-usama.anjum@collabora.… [8] https://lore.kernel.org/all/20221220162606.1595355-1-usama.anjum@collabora.… [9] https://lore.kernel.org/all/20230306213925.617814-1-peterx@redhat.com [10] https://lore.kernel.org/all/20230125144529.1630917-1-mdanylo@google.com * Original Cover letter from v8* Hello, Note: Soft-dirty pages and pages which have been written-to are synonyms. As kernel already has soft-dirty feature inside which we have given up to use, we are using written-to terminology while using UFFD async WP under the hood. This IOCTL, PAGEMAP_SCAN on pagemap file can be used to get and/or clear the info about page table entries. The following operations are supported in this ioctl: - Get the information if the pages have been written-to (PAGE_IS_WRITTEN), file mapped (PAGE_IS_FILE), present (PAGE_IS_PRESENT) or swapped (PAGE_IS_SWAPPED). - Write-protect the pages (PAGEMAP_WP_ENGAGE) to start finding which pages have been written-to. - Find pages which have been written-to and write protect the pages (atomic PAGE_IS_WRITTEN + PAGEMAP_WP_ENGAGE) It is possible to find and clear soft-dirty pages entirely in userspace. But it isn't efficient: - The mprotect and SIGSEGV handler for bookkeeping - The userfaultfd wp (synchronous) with the handler for bookkeeping Some benchmarks can be seen here[1]. This series adds features that weren't present earlier: - There is no atomic get soft-dirty/Written-to status and clear present in the kernel. - The pages which have been written-to can not be found in accurate way. (Kernel's soft-dirty PTE bit + sof_dirty VMA bit shows more soft-dirty pages than there actually are.) Historically, soft-dirty PTE bit tracking has been used in the CRIU project. The procfs interface is enough for finding the soft-dirty bit status and clearing the soft-dirty bit of all the pages of a process. We have the use case where we need to track the soft-dirty PTE bit for only specific pages on-demand. We need this tracking and clear mechanism of a region of memory while the process is running to emulate the getWriteWatch() syscall of Windows. *(Moved to using UFFD instead of soft-dirtyi feature to find pages which have been written-to from v7 patch series)*: Stop using the soft-dirty flags for finding which pages have been written to. It is too delicate and wrong as it shows more soft-dirty pages than the actual soft-dirty pages. There is no interest in correcting it [2][3] as this is how the feature was written years ago. It shouldn't be updated to changed behaviour. Peter Xu has suggested using the async version of the UFFD WP [4] as it is based inherently on the PTEs. So in this patch series, I've added a new mode to the UFFD which is asynchronous version of the write protect. When this variant of the UFFD WP is used, the page faults are resolved automatically by the kernel. The pages which have been written-to can be found by reading pagemap file (!PM_UFFD_WP). This feature can be used successfully to find which pages have been written to from the time the pages were write protected. This works just like the soft-dirty flag without showing any extra pages which aren't soft-dirty in reality. The information related to pages if the page is file mapped, present and swapped is required for the CRIU project [5][6]. The addition of the required mask, any mask, excluded mask and return masks are also required for the CRIU project [5]. The IOCTL returns the addresses of the pages which match the specific masks. The page addresses are returned in struct page_region in a compact form. The max_pages is needed to support a use case where user only wants to get a specific number of pages. So there is no need to find all the pages of interest in the range when max_pages is specified. The IOCTL returns when the maximum number of the pages are found. The max_pages is optional. If max_pages is specified, it must be equal or greater than the vec_size. This restriction is needed to handle worse case when one page_region only contains info of one page and it cannot be compacted. This is needed to emulate the Windows getWriteWatch() syscall. The patch series include the detailed selftest which can be used as an example for the uffd async wp test and PAGEMAP_IOCTL. It shows the interface usages as well. [1] https://lore.kernel.org/lkml/54d4c322-cd6e-eefd-b161-2af2b56aae24@collabora… [2] https://lore.kernel.org/all/20221220162606.1595355-1-usama.anjum@collabora.… [3] https://lore.kernel.org/all/20221122115007.2787017-1-usama.anjum@collabora.… [4] https://lore.kernel.org/all/Y6Hc2d+7eTKs7AiH@x1n [5] https://lore.kernel.org/all/YyiDg79flhWoMDZB@gmail.com/ [6] https://lore.kernel.org/all/20221014134802.1361436-1-mdanylo@google.com/ Regards, Muhammad Usama Anjum Muhammad Usama Anjum (4): fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs tools headers UAPI: Update linux/fs.h with the kernel sources mm/pagemap: add documentation of PAGEMAP_SCAN IOCTL selftests: mm: add pagemap ioctl tests Peter Xu (1): userfaultfd: UFFD_FEATURE_WP_ASYNC Documentation/admin-guide/mm/pagemap.rst | 56 + Documentation/admin-guide/mm/userfaultfd.rst | 35 + fs/proc/task_mmu.c | 478 +++++++ fs/userfaultfd.c | 26 +- include/linux/userfaultfd_k.h | 21 +- include/uapi/linux/fs.h | 53 + include/uapi/linux/userfaultfd.h | 9 +- mm/hugetlb.c | 32 +- mm/memory.c | 27 +- tools/include/uapi/linux/fs.h | 53 + tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 3 +- tools/testing/selftests/mm/config | 1 + tools/testing/selftests/mm/pagemap_ioctl.c | 1326 ++++++++++++++++++ tools/testing/selftests/mm/run_vmtests.sh | 4 + 15 files changed, 2102 insertions(+), 23 deletions(-) create mode 100644 tools/testing/selftests/mm/pagemap_ioctl.c mode change 100644 => 100755 tools/testing/selftests/mm/run_vmtests.sh -- 2.39.2

2 years, 5 months

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[PATCH 0/6] tools/nolibc: add stackprotector support for more architectures

by Thomas Weißschuh

Add stackprotector support for all remaining architectures, except s390. On s390 the stackprotectors are not supported in "global" mode; only "sysreg" mode which is not suppored in nolibc. The series also contains a small optimization to strace output during execution of nolibc-test. This series is based on the 20230415-nolibc-updates-4a branch of the nolibc tree. Signed-off-by: Thomas Weißschuh <linux(a)weissschuh.net> --- Thomas Weißschuh (6): selftests/nolibc: reduce syscalls during space padding tools/nolibc: riscv: add stackprotector support tools/nolibc: aarch64: add stackprotector support tools/nolibc: arm: add stackprotector support tools/nolibc: loongarch: add stackprotector support tools/nolibc: mips: add stackprotector support tools/include/nolibc/arch-aarch64.h | 7 ++++++- tools/include/nolibc/arch-arm.h | 7 ++++++- tools/include/nolibc/arch-loongarch.h | 7 ++++++- tools/include/nolibc/arch-mips.h | 8 +++++++- tools/include/nolibc/arch-riscv.h | 7 ++++++- tools/testing/selftests/nolibc/Makefile | 5 +++++ tools/testing/selftests/nolibc/nolibc-test.c | 15 +++++++++++---- 7 files changed, 47 insertions(+), 9 deletions(-) --- base-commit: e35214ea9db7477a02e67a8b412e8046534bb97c change-id: 20230408-nolibc-stackprotector-archs-42244674616e Best regards, -- Thomas Weißschuh <linux(a)weissschuh.net>

2 years, 5 months

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[PATCH] kselftest/arm64: Add a smoke test for ptracing hardware break/watch points

by Mark Brown

There was a report that the hardware breakpoints and watch points weren't reporting the debug architecture version as expected, they were reporting a version of 0 which is not defined in the architecture. This happens when running in a KVM guest if the host has a debug architecture version not supported by KVM, it in turn confuses GDB which rejects any debug architecture version it does not know about. Add a test that covers that situation and while we're at it reports the debug architecture version and number of slots available to aid with figuring out problems that may arise. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- tools/testing/selftests/arm64/abi/ptrace.c | 32 +++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/arm64/abi/ptrace.c b/tools/testing/selftests/arm64/abi/ptrace.c index be952511af22..abe4d58d731d 100644 --- a/tools/testing/selftests/arm64/abi/ptrace.c +++ b/tools/testing/selftests/arm64/abi/ptrace.c @@ -20,7 +20,7 @@ #include "../../kselftest.h" -#define EXPECTED_TESTS 7 +#define EXPECTED_TESTS 11 #define MAX_TPIDRS 2 @@ -132,6 +132,34 @@ static void test_tpidr(pid_t child) } } +static void test_hw_debug(pid_t child, int type, const char *type_name) +{ + struct user_hwdebug_state state; + struct iovec iov; + int slots, arch, ret; + + iov.iov_len = sizeof(state); + iov.iov_base = &state; + + /* Should be able to read the values */ + ret = ptrace(PTRACE_GETREGSET, child, type, &iov); + ksft_test_result(ret == 0, "read_%s\n", type_name); + + if (ret == 0) { + /* Low 8 bits is the number of slots, next 4 bits the arch */ + slots = state.dbg_info & 0xff; + arch = (state.dbg_info >> 8) & 0xf; + + ksft_print_msg("%s version %d with %d slots\n", type_name, + arch, slots); + + /* Zero is not currently architecturally valid */ + ksft_test_result(arch, "%s_arch_set\n", type_name); + } else { + ksft_test_result_skip("%s_arch_set\n"); + } +} + static int do_child(void) { if (ptrace(PTRACE_TRACEME, -1, NULL, NULL)) @@ -207,6 +235,8 @@ static int do_parent(pid_t child) ksft_print_msg("Parent is %d, child is %d\n", getpid(), child); test_tpidr(child); + test_hw_debug(child, NT_ARM_HW_WATCH, "NT_ARM_HW_WATCH"); + test_hw_debug(child, NT_ARM_HW_BREAK, "NT_ARM_HW_BREAK"); ret = EXIT_SUCCESS; --- base-commit: e8d018dd0257f744ca50a729e3d042cf2ec9da65 change-id: 20230414-arm64-test-hw-breakpoint-83fe02f607fc Best regards, -- Mark Brown <broonie(a)kernel.org>

2 years, 5 months

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Re: [PATCH v8 3/3] selftests/mm: add new selftests for KSM

by David Hildenbrand

> +/* Verify that KSM can be enabled / queried with prctl. */ > +static void test_prctl(void) > +{ > + int ret; > + > + ksft_print_msg("[RUN] %s\n", __func__); > + > + ret = prctl(PR_SET_MEMORY_MERGE, 1, 0, 0, 0); > + if (ret < 0 && errno == EINVAL) { > + ksft_test_result_skip("PR_SET_MEMORY_MERGE not supported\n"); > + return; > + } else if (ret) { > + ksft_test_result_fail("PR_SET_MEMORY_MERGE=1 failed\n"); > + } Just realized we're missing a "return;" in case of the failure here. -- Thanks, David / dhildenb

2 years, 5 months

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Re: [PATCH v8 1/3] mm: add new api to enable ksm per process

by David Hildenbrand

> +static void __ksm_add_vma(struct vm_area_struct *vma) > +{ > + unsigned long vm_flags = vma->vm_flags; > + > + if (vm_flags & VM_MERGEABLE) > + return; > + > + if (vma_ksm_compatible(vma)) { > + vm_flags |= VM_MERGEABLE; > + vm_flags_reset(vma, vm_flags); > + } > +} We can do the following simplification on top: diff --git a/mm/ksm.c b/mm/ksm.c index 905c8edce5cf..26e7f585d65d 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2511,15 +2511,11 @@ static int ksm_scan_thread(void *nothing) static void __ksm_add_vma(struct vm_area_struct *vma) { - unsigned long vm_flags = vma->vm_flags; - - if (vm_flags & VM_MERGEABLE) + if (vma->vm_flags & VM_MERGEABLE) return; - if (vma_ksm_compatible(vma)) { - vm_flags |= VM_MERGEABLE; - vm_flags_reset(vma, vm_flags); - } + if (vma_ksm_compatible(vma)) + vm_flags_set(vma, VM_MERGEABLE); } /** -- 2.39.2 I have some patches based on your patch set (handling/testing unmerging whens setting PR_SET_MEMORY_MERGE=0. Will send out once you changes are queued. -- Thanks, David / dhildenb

2 years, 5 months

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Re: new order

by FASTWAYBASE.US94＠consultant.com

Dea Sir. Please see attached new order and revert to us the delivery date/ FOB also inform us payment terms. Best Regards Susan Purchase Manager.

2 years, 5 months

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[RFC PATCH v2 0/3] kunit: Deferred action helpers

by David Gow

This is a follow-up to the kunit_defer() parts of 'KUnit device API proposal'[1], with a number of changes suggested by Matti Vaittinen, Maxime Ripard and Benjamin Berg. Most notably, kunit_defer() has been renamed to kunit_add_action(), in order to match the equivalent devres API[2]. Likewise: kunit_defer_cancel() has become kunit_remove_action(), and kunit_defer_trigger() has become kunit_release_action(). The _token() versions of these APIs remain, for the moment, even though they're a bit more awkward and less useful, as they have two advantages: 1. They're faster, as the action doesn't need to be looked up. 2. They provide more flexibility in the ordering of actions in cases where several identical actions are interleaved with other, different actions. Similarly, the internal_gfp argument remains for now, as this is useful in implementing kunit_kalloc() and similar. The implementation now uses a single allocation for both the kunit_resource and the kunit_action_ctx (previously kunit_defer_ctx). The 'cancellation token' is now of type 'struct kunit_action_ctx', instead of void*. Tests have been added to the kunit-resource-test suite which exercise this functionality. Similarly, the kunit executor tests and kunit allocation functions have been updated to make use of this API. I'd love to hear any further thoughts! Cheers, -- David [1]: https://lore.kernel.org/linux-kselftest/20230325043104.3761770-1-davidgow@g… [2]: https://docs.kernel.org/driver-api/basics.html#c.devm_add_action David Gow (3): kunit: Add kunit_add_action() to defer a call until test exit kunit: executor_test: Use kunit_add_action() kunit: kmalloc_array: Use kunit_add_action() include/kunit/resource.h | 89 +++++++++++++++++++++++++++ lib/kunit/executor_test.c | 12 ++-- lib/kunit/kunit-test.c | 123 +++++++++++++++++++++++++++++++++++++- lib/kunit/resource.c | 99 ++++++++++++++++++++++++++++++ lib/kunit/test.c | 48 +++------------ 5 files changed, 323 insertions(+), 48 deletions(-) -- 2.40.0.348.gf938b09366-goog

2 years, 5 months

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Re: [PATCH v8 3/3] selftests/mm: add new selftests for KSM

by David Hildenbrand

On 16.04.23 00:59, Stefan Roesch wrote: > This adds three new tests to the selftests for KSM. These tests use the > new prctl API's to enable and disable KSM. > > 1) add new prctl flags to prctl header file in tools dir > > This adds the new prctl flags to the include file prct.h in the > tools directory. This makes sure they are available for testing. > > 2) add KSM prctl merge test to ksm_tests > > This adds the -t option to the ksm_tests program. The -t flag > allows to specify if it should use madvise or prctl ksm merging. > > 3) add two functions for debugging merge outcome for ksm_tests > > This adds two functions to report the metrics in /proc/self/ksm_stat > and /sys/kernel/debug/mm/ksm. The debug output is enabled with the > -d option. > > 4) add KSM prctl test to ksm_functional_tests > > This adds a test to the ksm_functional_test that verifies that the > prctl system call to enable / disable KSM works. > > 5) add KSM fork test to ksm_functional_test > > Add fork test to verify that the MMF_VM_MERGE_ANY flag is inherited > by the child process. > > Signed-off-by: Stefan Roesch <shr(a)devkernel.io> > Cc: Bagas Sanjaya <bagasdotme(a)gmail.com> > Cc: David Hildenbrand <david(a)redhat.com> > Cc: Johannes Weiner <hannes(a)cmpxchg.org> > Cc: Michal Hocko <mhocko(a)suse.com> > Cc: Rik van Riel <riel(a)surriel.com> > Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> > --- Thanks! Acked-by: David Hildenbrand <david(a)redhat.com> -- Thanks, David / dhildenb

2 years, 5 months

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Re: [PATCH v7 3/3] selftests/mm: add new selftests for KSM

by David Hildenbrand

Thanks for moving the functional tests. Some more feedback forksm_functional_tests change. Writing tests in the ksft testing framework can be a bit "special". I'm seeing some weird test failures due to prctl(PR_GET_MEMORY_MERGE, 0) Apparently, these go away when using prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0) to explicitly force the other values to 0. Most probably, we should do that for PR_SET_MEMORY_MERGE as well (especially if we check for the arguments as well). [...] > @@ -15,8 +15,10 @@ > #include <errno.h> > #include <fcntl.h> > #include <sys/mman.h> > +#include <sys/prctl.h> > #include <sys/syscall.h> > #include <sys/ioctl.h> > +#include <sys/wait.h> > #include <linux/userfaultfd.h> > > #include "../kselftest.h" > @@ -326,9 +328,80 @@ static void test_unmerge_uffd_wp(void) > } > #endif > > +/* Verify that KSM can be enabled / queried with prctl. */ > +static void test_ksm_prctl(void) Maybe call this "test_prctl", because after all, these are all KSM tests. > +{ > + bool ret = false; > + int is_on; > + int is_off; > + > + ksft_print_msg("[RUN] %s\n", __func__); > + > + if (prctl(PR_SET_MEMORY_MERGE, 1)) { > + perror("prctl set"); > + goto out; > + } > + > + is_on = prctl(PR_GET_MEMORY_MERGE, 0); > + if (prctl(PR_SET_MEMORY_MERGE, 0)) { > + perror("prctl set"); > + goto out; > + } > + > + is_off = prctl(PR_GET_MEMORY_MERGE, 0); > + if (is_on && is_off) > + ret = true; > + > +out: > + ksft_test_result(ret, "prctl get / set\n"); The test fails if the kernel does not support PR_SET_MEMORY_MERGE. I'd modify this test to: (1) skip if the first PR_SET_MEMORY_MERGE=1 failed with EINVAL. (2) distinguish for PR_GET_MEMORY_MERGE whether it returned an error or whether it returned a wrong value. Feel free to keep that as is, whatever you prefer. (3) exit early for all failures, you get exactly one expected skip/pass/fail for the test and use specific test failure messages. (4) Pass "0" for all other arguments of prctl. Something like: static void test_prctl(void) { int ret; ksft_print_msg("[RUN] %s\n", __func__); ret = prctl(PR_SET_MEMORY_MERGE, 1, 0, 0, 0); if (ret < 0 && errno == EINVAL){ ksft_test_result_skip("PR_SET_MEMORY_MERGE not supported\n"); return; } else if (ret) { ksft_test_result_fail("PR_SET_MEMORY_MERGE=1 failed\n"); return; } ret = prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0); if (ret < 0) { ksft_test_result_fail("PR_GET_MEMORY_MERGE failed\n"); return; } else if (ret != 1) { ksft_test_result_fail("PR_SET_MEMORY_MERGE=1 not effective\n"); return; } ret = prctl(PR_SET_MEMORY_MERGE, 0, 0, 0, 0); if (ret){ ksft_test_result_fail("PR_SET_MEMORY_MERGE=0 failed\n"); return; } ret = prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0); if (ret < 0) { ksft_test_result_fail("PR_GET_MEMORY_MERGE failed\n"); return; } else if (ret != 0) { ksft_test_result_fail("PR_SET_MEMORY_MERGE=0 not effective\n"); return; } ksft_test_result_pass("Setting/clearing PR_SET_MEMORY_MERGE works\n"); } > +} > + > +/* Verify that prctl ksm flag is inherited. */ > +static void test_ksm_fork(void) Maybe call it "test_prctl_fork" > +{ > + int status; > + bool ret = false; > + pid_t child_pid; > + > + ksft_print_msg("[RUN] %s\n", __func__); > + > + if (prctl(PR_SET_MEMORY_MERGE, 1)) { > + ksft_test_result_fail("prctl failed\n"); > + goto out; > + } > + > + child_pid = fork(); > + if (child_pid == 0) { > + int is_on = > + > + if (!is_on) > + exit(-1); > + > + exit(0); > + } > + > + if (child_pid < 0) { > + ksft_test_result_fail("child pid < 0\n"); > + goto out;> + > + if (waitpid(child_pid, &status, 0) < 0 || WEXITSTATUS(status) != 0) { > + ksft_test_result_fail("wait pid < 0\n"); > + goto out; > + } > + > + if (prctl(PR_SET_MEMORY_MERGE, 0)) > + ksft_test_result_fail("prctl 2 failed\n"); > + else > + ret = true; > + > +out: > + ksft_test_result(ret, "ksm_flag is inherited\n"); > +} Again, test fails if kernel support is not around. I'd modify this test to: (1) skip if the first PR_SET_MEMORY_MERGE=1 failed with EINVAL just as in the other test. (2) Use a simple exit(prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0)); in the child. (3) exit early for all failures, you get exactly one expected skip/pass/fail for the test and use specific test failure messages. (4) Split up the waitpid() check to test what failed. (5) Pass "0" for all other arguments of prctl. Something like: static void test_prctl_fork(void) { int ret, status; pid_t child_pid; ksft_print_msg("[RUN] %s\n", __func__); ret = prctl(PR_SET_MEMORY_MERGE, 1, 0, 0, 0); if (ret < 0 && errno == EINVAL){ ksft_test_result_skip("PR_SET_MEMORY_MERGE not supported\n"); return; } else if (ret) { ksft_test_result_fail("PR_SET_MEMORY_MERGE=1 failed\n"); return; } child_pid = fork(); if (!child_pid) { exit(prctl(PR_GET_MEMORY_MERGE, 0, 0, 0, 0)); } else if (child_pid < 0) { ksft_test_result_fail("fork() failed\n"); return; } if (waitpid(child_pid, &status, 0) < 0) { ksft_test_result_fail("waitpid() failed\n"); return; } else if (WEXITSTATUS(status) != 1) { ksft_test_result_fail("unexpected PR_GET_MEMORY_MERGE result in child\n"); return; } if (prctl(PR_SET_MEMORY_MERGE, 0, 0, 0, 0)) { ksft_test_result_fail("PR_SET_MEMORY_MERGE=0 failed\n"); return; } ksft_test_result_pass("PR_SET_MEMORY_MERGE value is inherited\n"); } > + > int main(int argc, char **argv) > { > - unsigned int tests = 2; > + unsigned int tests = 6; Assuming you execute exactly one ksft_test_result_skip/fail/pass on every path of your two test, this would become "4". > int err; > > #ifdef __NR_userfaultfd > @@ -358,6 +431,8 @@ int main(int argc, char **argv) > #ifdef __NR_userfaultfd > test_unmerge_uffd_wp(); > #endif > + test_ksm_prctl(); > + test_ksm_fork(); > With above outlined changes (feel free to integrate what you consider valuable), on an older kernel I get: $ sudo ./ksm_functional_tests TAP version 13 1..5 # [RUN] test_unmerge ok 1 Pages were unmerged # [RUN] test_unmerge_discarded ok 2 Pages were unmerged # [RUN] test_unmerge_uffd_wp ok 3 Pages were unmerged # [RUN] test_prctl ok 4 # SKIP PR_SET_MEMORY_MERGE not supported # [RUN] test_prctl_fork ok 5 # SKIP PR_SET_MEMORY_MERGE not supported # Totals: pass:3 fail:0 xfail:0 xpass:0 skip:2 error:0 On a kernel with your patch #1: # ./ksm_functional_tests TAP version 13 1..5 # [RUN] test_unmerge ok 1 Pages were unmerged # [RUN] test_unmerge_discarded ok 2 Pages were unmerged # [RUN] test_unmerge_uffd_wp ok 3 Pages were unmerged # [RUN] test_prctl ok 4 Setting/clearing PR_SET_MEMORY_MERGE works # [RUN] test_prctl_fork ok 5 PR_SET_MEMORY_MERGE value is inherited # Totals: pass:5 fail:0 xfail:0 xpass:0 skip:0 error:0 > err = ksft_get_fail_cnt(); > if (err) > diff --git a/tools/testing/selftests/mm/ksm_tests.c b/tools/testing/selftests/mm/ksm_tests.c > index f9eb4d67e0dd..35b3828d44b4 100644 > --- a/tools/testing/selftests/mm/ksm_tests.c > +++ b/tools/testing/selftests/mm/ksm_tests.c > @@ -1,6 +1,8 @@ > // SPDX-License-Identifier: GPL-2.0 [...] Changes to ksm_tests mostly look good. Two comments: > - if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout)) > + if (ksm_merge_pages(merge_type, map_ptr, page_size * page_count, start_time, timeout)) > goto err_out; > > /* verify that the right number of pages are merged */ > if (assert_ksm_pages_count(page_count)) { > printf("OK\n"); > - munmap(map_ptr, page_size * page_count); > + if (merge_type == KSM_MERGE_MADVISE) > + munmap(map_ptr, page_size * page_count); > + else if (merge_type == KSM_MERGE_PRCTL) > + prctl(PR_SET_MEMORY_MERGE, 0); Are you sure that we don't want to unmap here? I'd assume we want to unmap in either way. [...] > + case 'd': > + debug = 1; > + break; > case 's': > size_MB = atoi(optarg); > if (size_MB <= 0) { > printf("Size must be greater than 0\n"); > return KSFT_FAIL; > } > + case 't': > + { > + int tmp = atoi(optarg); > + > + if (tmp < 0 || tmp > KSM_MERGE_LAST) { > + printf("Invalid merge type\n"); > + return KSFT_FAIL; > + } > + merge_type = atoi(optarg); You can simply reuse tmp merge_type = tmp; -- Thanks, David / dhildenb

2 years, 5 months

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[PATCH net-next 0/5] mptcp: various small cleanups

by Matthieu Baerts

Patch 1 makes a function static because it is only used in one file. Patch 2 adds info about the git trees we use to help occasional devs. Patch 3 removes an unused variable. Patch 4 removes duplicated entries from the help menu of a tool used in MPTCP selftests. Patch 5 removes some ShellCheck warnings in mptcp_join.sh selftest. Only very minor improvements then. Signed-off-by: Matthieu Baerts <matthieu.baerts(a)tessares.net> --- Geliang Tang (1): mptcp: make userspace_pm_append_new_local_addr static Matthieu Baerts (4): MAINTAINERS: add git trees for MPTCP mptcp: remove unused 'remaining' variable selftests: mptcp: remove duplicated entries in usage selftests: mptcp: join: fix ShellCheck warnings MAINTAINERS | 2 ++ net/mptcp/options.c | 7 ++----- net/mptcp/pm_userspace.c | 4 ++-- net/mptcp/protocol.h | 2 -- tools/testing/selftests/net/mptcp/mptcp_connect.c | 8 ++++---- tools/testing/selftests/net/mptcp/mptcp_join.sh | 10 ++++++++-- 6 files changed, 18 insertions(+), 15 deletions(-) --- base-commit: c11d2e718c792468e67389b506451eddf26c2dac change-id: 20230414-upstream-net-next-20230414-mptcp-small-cleanups-1cba986990b1 Best regards, -- Matthieu Baerts <matthieu.baerts(a)tessares.net>

2 years, 5 months

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