- Linux-kselftest-mirror - lists.linaro.org

[RFC PATCH 0/3] Use TAP in some more KVM selftests

by Thomas Huth

Many KVM selftests are completely silent. This has the disadvantage for the users that they do not know what's going on here. For example, some time ago, a tester asked me how to know whether a certain new sub-test has been added to one of the s390x test binaries or not (which he didn't compile on his own), which is hard to judge when there is no output. So I finally went ahead and implemented TAP output in the s390x-specific tests some months ago. Now I wonder whether that could be a good strategy for the x86 and generic tests, too? As a little RFC patch series, I've converted three more KVM selftests to use TAP output. If we decide that this is the right way to go, I can work on other tests later, too. Thomas Huth (3): KVM: selftests: Use TAP interface in the kvm_binary_stats_test KVM: selftests: x86: Use TAP interface in the sync_regs test KVM: selftests: x86: Use TAP interface in the tsc_msrs_test .../selftests/kvm/kvm_binary_stats_test.c | 11 +- .../selftests/kvm/x86_64/sync_regs_test.c | 113 ++++++++++++++---- .../selftests/kvm/x86_64/tsc_msrs_test.c | 16 ++- 3 files changed, 114 insertions(+), 26 deletions(-) -- 2.31.1

2 years, 10 months

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[PATCH v3 0/5] Some improvements of resctrl selftest

by Shaopeng Tan

Hello, The aim of this patch series is to improve the resctrl selftest. Without these fixes, some unnecessary processing will be executed and test results will be confusing. There is no behavior change in test themselves. [patch 1] Make write_schemata() run to set up shemata with 100% allocation on first run in MBM test. [patch 2] The MBA test result message is always output as "ok", make output message to be "not ok" if MBA check result is failed. [patch 3] When a child process is created by fork(), the buffer of the parent process is also copied. Flush the buffer before executing fork(). [patch 4] Add a signal handler to cleanup properly before exiting the parent process, if there is an error occurs after creating a child process with fork() in the CAT test. [patch 5] Before exiting each test CMT/CAT/MBM/MBA, clear test result files function cat/cmt/mbm/mba_test_cleanup() are called twice. Delete once. This patch series is based on Linux v6.1-rc3 Difference from v2: Moved [PATCH v2 3/4] to the last and insert patch 4 before it. [patch 1] Fixed the typo miss in the changelog and initialized *p(resctrl_val_param) before use it. And since there was no MBM processing in write_schemata(), added it. [patch 4] A signal handler is introduced in this patch. With this patch, patch 5 clear duplicate code cat/cmt/mbm/mba_test_cleanup() without falling into the indicated trap. https://lore.kernel.org/lkml/bdb19cf6-dd4b-2042-7cda-7f6108e543aa@intel.com/ Pervious versions of this series: [v1] https://lore.kernel.org/lkml/20220914015147.3071025-1-tan.shaopeng@jp.fujit… [v2] https://lore.kernel.org/lkml/20221005013933.1486054-1-tan.shaopeng@jp.fujit… Shaopeng Tan (5): selftests/resctrl: Fix set up schemata with 100% allocation on first run in MBM test selftests/resctrl: Return MBA check result and make it to output message selftests/resctrl: Flush stdout file buffer before executing fork() selftests/resctrl: Cleanup properly when an error occurs in CAT test. selftests/resctrl: Remove duplicate codes that clear each test result file tools/testing/selftests/resctrl/cat_test.c | 29 +++++++++++++------ tools/testing/selftests/resctrl/mba_test.c | 8 ++--- tools/testing/selftests/resctrl/mbm_test.c | 13 +++++---- .../testing/selftests/resctrl/resctrl_tests.c | 4 --- tools/testing/selftests/resctrl/resctrl_val.c | 1 + tools/testing/selftests/resctrl/resctrlfs.c | 5 +++- 6 files changed, 36 insertions(+), 24 deletions(-) -- 2.27.0

2 years, 10 months

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kselftest rtctests failed on arm64 Raspberry Pi 4 - rtctest.c:34:date_read:Expected -1 (-1) != self->fd (-1)

by Naresh Kamboju

kselftest rtctests failed on arm64 Raspberry Pi 4 Model B device and passed on other devices and qemu emulators. Please refer to the full logs and test comparison results links. Reported-by: Linux Kernel Functional Testing <lkft(a)linaro.org> Test run log: ------------- [ 248.627989] kselftest: Running tests in rtc TAP version 13 1..1 # selftests: rtc: rtctest [ 249.116824] audit: type=1701 audit(1651167970.071:12): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=2818 comm=\"rtctest\" exe=\"/opt/kselftests/default-in-kernel/rtc/rtctest\" sig=6 res=1 [ 249.133837] audit: type=1701 audit(1651167970.079:13): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=2819 comm=\"rtctest\" exe=\"/opt/kselftests/default-in-kernel/rtc/rtctest\" sig=6 res=1 [ 249.151179] audit: type=1701 audit(1651167970.083:14): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=2820 comm=\"rtctest\" exe=\"/opt/kselftests/default-in-kernel/rtc/rtctest\" sig=6 res=1 [ 249.168401] audit: type=1701 audit(1651167970.091:15): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=2821 comm=\"rtctest\" exe=\"/opt/kselftests/default-in-kernel/rtc/rtctest\" sig=6 res=1 [ 249.185406] audit: type=1701 audit(1651167970.095:16): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=2822 comm=\"rtctest\" exe=\"/opt/kselftests/default-in-kernel/rtc/rtctest\" sig=6 res=1 [ 249.202343] audit: type=1701 audit(1651167970.103:17): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=2823 comm=\"rtctest\" exe=\"/opt/kselftests/default-in-kernel/rtc/rtctest\" sig=6 res=1 #[ 249.219262] audit: type=1701 audit(1651167970.111:18): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=2824 comm=\"rtctest\" exe=\"/opt/kselftests/default-in-kernel/rtc/rtctest\" sig=6 res=1 [ 249.236233] audit: type=1701 audit(1651167970.115:19): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=2825 comm=\"rtctest\" exe=\"/opt/kselftests/default-in-kernel/rtc/rtctest\" sig=6 res=1 TAP version 13 # 1..8 # # Starting 8 tests from 2 test cases. # # RUN rtc.date_read ... # # rtctest.c:34:date_read:Expected -1 (-1) != self->fd (-1) # # date_read: Test terminated by assertion # # FAIL rtc.date_read # not ok 1 rtc.date_read # # RUN rtc.date_read_loop ... # # rtctest.c:34:date_read_loop:Expected -1 (-1) != self->fd (-1) # # date_read_loop: Test terminated by assertion # # FAIL rtc.date_read_loop # not ok 2 rtc.date_read_loop # # RUN rtc.uie_read ... # # rtctest.c:34:uie_read:Expected -1 (-1) != self->fd (-1) # # uie_read: Test terminated by assertion # # FAIL rtc.uie_read # not ok 3 rtc.uie_read # # RUN rtc.uie_select ... # # rtctest.c:34:uie_select:Expected -1 (-1) != self->fd (-1) # # uie_select: Test terminated by assertion # # FAIL rtc.uie_select # not ok 4 rtc.uie_select # # RUN rtc.alarm_alm_set ... # # rtctest.c:34:alarm_alm_set:Expected -1 (-1) != self->fd (-1) # # alarm_alm_set: Test terminated by assertion # # FAIL rtc.alarm_alm_set # not ok 5 rtc.alarm_alm_set # # RUN rtc.alarm_wkalm_set ... # # rtctest.c:34:alarm_wkalm_set:Expected -1 (-1) != self->fd (-1) # # alarm_wkalm_set: Test terminated by assertion # # FAIL rtc.alarm_wkalm_set # not ok 6 rtc.alarm_wkalm_set # # RUN rtc.alarm_alm_set_minute ... # # rtctest.c:34:alarm_alm_set_minute:Expected -1 (-1) != self->fd (-1) # # alarm_alm_set_minute: Test terminated by assertion # # FAIL rtc.alarm_alm_set_minute # not ok 7 rtc.alarm_alm_set_minute # # RUN rtc.alarm_wkalm_set_minute ... # # rtctest.c:34:alarm_wkalm_set_minute:Expected -1 (-1) != self->fd (-1) # # alarm_wkalm_set_minute: Test terminated by assertion # # FAIL rtc.alarm_wkalm_set_minute # not ok 8 rtc.alarm_wkalm_set_minute # # FAILED: 0 / 8 tests passed. # # Totals: pass:0 fail:8 xfail:0 xpass:0 skip:0 error:0 not ok 1 selftests: rtc: rtctest # exit=1 Test results details, https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20221107/te… Test results compare, https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20221107/te… Test detailed log, https://lkft.validation.linaro.org/scheduler/job/5812742#L1759 metadata: git_ref: master git_repo: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next git_sha: d8e87774068af213ab5b058b1b114dc397b577aa git_describe: next-20221107 kernel_version: 6.1.0-rc3 kernel-config: https://builds.tuxbuild.com/2HChVOSNxUpvfAfLTnaK7zyTdUi/config build-url: https://gitlab.com/Linaro/lkft/mirrors/next/linux-next/-/pipelines/687092361 artifact-location: https://builds.tuxbuild.com/2HChVOSNxUpvfAfLTnaK7zyTdUi toolchain: gcc-11 -- Linaro QA https://qa-reports.linaro.org

2 years, 10 months

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[PATCH RESEND 0/7] KUnit documentation rewording

by Bagas Sanjaya

Hi everyone, sorry for quickly resending this patch series due to duplicated patch [7/7] sent as result of amending the corresponding commit. The proses written in KUnit documentation are IMO incomprehensible (my brain has to process what the meaning of words used) and different from wordings that I normally read from technical writings. Thus, rewrite these using clearer words. Anyway, it's great to see native English speakers help reviewing this series. The first two patches are v3 of rewriting "Writing Your First Test" section of "Getting Started" patch [1], which was submitted about a month ago. The rest are actual documentation rewriting. Note that this series only rewrites intro, test writing and running docs. [1]: https://lore.kernel.org/lkml/20220929132549.56452-1-bagasdotme@gmail.com/ Bagas Sanjaya (7): Documentation: kunit: rewrite "Writing Your First Test" section Documentation: kunit: align instruction code blocks Documentation: kunit: rewrite the rest of "Getting Started" documentation Documentation: kunit: move introduction to its own document Documentation: kunit: rewrite "Running tests with kunit_tool" Documentation: kunit: rewrite "Run Tests without kunit_tool" Documentation: kunit: rewrite "Writing tests" Documentation/admin-guide/README.rst | 2 + Documentation/dev-tools/kunit/index.rst | 93 +---- Documentation/dev-tools/kunit/intro.rst | 61 ++++ Documentation/dev-tools/kunit/run_manual.rst | 68 ++-- Documentation/dev-tools/kunit/run_wrapper.rst | 302 ++++++---------- Documentation/dev-tools/kunit/start.rst | 264 +++++++------- Documentation/dev-tools/kunit/usage.rst | 322 ++++++++++-------- 7 files changed, 483 insertions(+), 629 deletions(-) create mode 100644 Documentation/dev-tools/kunit/intro.rst base-commit: de3ee3f63400a23954e7c1ad1cb8c20f29ab6fe3 -- An old man doll... just what I always wanted! - Clara

2 years, 10 months

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[RFC PATCH 3/3] KVM: selftests: Test user hypercalls

by Oliver Upton

Signed-off-by: Oliver Upton <oliver.upton(a)linux.dev> --- tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/aarch64/user_hypercalls.c | 130 ++++++++++++++++++ 3 files changed, 132 insertions(+) create mode 100644 tools/testing/selftests/kvm/aarch64/user_hypercalls.c diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore index 2f0d705db9db..4f45e987985f 100644 --- a/tools/testing/selftests/kvm/.gitignore +++ b/tools/testing/selftests/kvm/.gitignore @@ -5,6 +5,7 @@ /aarch64/get-reg-list /aarch64/hypercalls /aarch64/psci_test +/aarch64/user_hypercalls /aarch64/vcpu_width_config /aarch64/vgic_init /aarch64/vgic_irq diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index 0172eb6cb6ee..8ac1988ea669 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -153,6 +153,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list TEST_GEN_PROGS_aarch64 += aarch64/hypercalls TEST_GEN_PROGS_aarch64 += aarch64/psci_test +TEST_GEN_PROGS_aarch64 += aarch64/user_hypercalls TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config TEST_GEN_PROGS_aarch64 += aarch64/vgic_init TEST_GEN_PROGS_aarch64 += aarch64/vgic_irq diff --git a/tools/testing/selftests/kvm/aarch64/user_hypercalls.c b/tools/testing/selftests/kvm/aarch64/user_hypercalls.c new file mode 100644 index 000000000000..94ac821c5474 --- /dev/null +++ b/tools/testing/selftests/kvm/aarch64/user_hypercalls.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include <linux/arm-smccc.h> + +#include "kvm_util.h" +#include "processor.h" +#include "test_util.h" + +struct test_case { + uint64_t cap; + uint32_t function; + uint64_t args[6]; +}; + +#define TEST_OWNER(name) \ +{ \ + .cap = BIT_ULL(KVM_ARM_USER_HYPERCALL_OWNER_ ## name), \ + .function = ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_32, \ + ARM_SMCCC_OWNER_ ## name, \ + 0), \ + .args = { \ + __LINE__, \ + __LINE__ + 1, \ + __LINE__ + 2, \ + __LINE__ + 3, \ + __LINE__ + 4, \ + __LINE__ + 5, \ + }, \ +}, \ +{ \ + .cap = BIT_ULL(KVM_ARM_USER_HYPERCALL_OWNER_ ## name), \ + .function = ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, \ + ARM_SMCCC_SMC_64, \ + ARM_SMCCC_OWNER_ ## name, \ + 0), \ + .args = { \ + __LINE__, \ + __LINE__ + 1, \ + __LINE__ + 2, \ + __LINE__ + 3, \ + __LINE__ + 4, \ + __LINE__ + 5, \ + }, \ +} \ + +static struct test_case test_cases[] = { + TEST_OWNER(ARCH), + TEST_OWNER(CPU), + TEST_OWNER(SIP), + TEST_OWNER(OEM), + TEST_OWNER(STANDARD), + TEST_OWNER(STANDARD_HYP), + TEST_OWNER(VENDOR_HYP), + TEST_OWNER(TRUSTED_APP), + TEST_OWNER(TRUSTED_OS), +}; + +static void guest_main(const struct test_case *test) +{ + struct arm_smccc_res unused; + + smccc_hvc(test->function, test->args[0], test->args[1], test->args[2], + test->args[3], test->args[4], test->args[5], 0, &unused); + + GUEST_ASSERT(0); +} + +static void handle_hvc(const struct test_case *test, struct kvm_vcpu *vcpu) +{ + struct kvm_run *run = vcpu->run; + + TEST_ASSERT(run->hypercall.nr == test->function, + "unexpected function ID: %llx (expected %x)", + run->hypercall.nr, test->function); + + TEST_ASSERT(!memcmp(&run->hypercall.args, &test->args, sizeof(test->args)), + "unexpected hypercall arguments"); +} + +static void handle_ucall(struct kvm_vcpu *vcpu) +{ + struct ucall uc; + + switch (get_ucall(vcpu, &uc)) { + case UCALL_ABORT: + REPORT_GUEST_ASSERT(uc); + break; + default: + TEST_FAIL("unhandled ucall: %lu", uc.cmd); + } +} + +static void run_test(const struct test_case *test) +{ + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + + vm = vm_create_with_one_vcpu(&vcpu, guest_main); + vm_enable_cap(vm, KVM_CAP_ARM_USER_HYPERCALLS, test->cap); + ucall_init(vm, NULL); + + vcpu_args_set(vcpu, 1, test); + + vcpu_run(vcpu); + switch (vcpu->run->exit_reason) { + case KVM_EXIT_HYPERCALL: + handle_hvc(test, vcpu); + break; + case KVM_EXIT_MMIO: + handle_ucall(vcpu); + break; + default: + TEST_FAIL("unhandled exit reason: %u (%s)", vcpu->run->exit_reason, + exit_reason_str(vcpu->run->exit_reason)); + } + + ucall_uninit(vm); + kvm_vm_free(vm); +} + +int main(void) +{ + int i; + + TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_USER_HYPERCALLS)); + + for (i = 0; i < ARRAY_SIZE(test_cases); i++) + run_test(&test_cases[i]); +} -- 2.38.1.431.g37b22c650d-goog

2 years, 10 months

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Re: [PATCH v4 15/17] iommufd: Add a selftest

by Matthew Rosato

On 11/7/22 7:49 PM, Jason Gunthorpe wrote: > Cover the essential functionality of the iommufd with a directed > test. This aims to achieve reasonable functional coverage using the > in-kernel self test framework. > > It provides a mock kernel module for the iommu_domain that allows it to > run without any HW and the mocking provides a way to directly validate > that the PFNs loaded into the iommu_domain are correct. > > The mock also simulates the rare case of PAGE_SIZE > iommu page size as > the mock will operate at a 2K iommu page size. This allows exercising all > of the calculations to support this mismatch. > > This allows achieving high coverage of the corner cases in the iopt_pages. > > However, it is an unusually invasive config option to enable all of > this. The config option should not be enabled in a production kernel. > > Tested-by: Nicolin Chen <nicolinc(a)nvidia.com> > Signed-off-by: Jason Gunthorpe <jgg(a)nvidia.com> > Signed-off-by: Nicolin Chen <nicolinc(a)nvidia.com> > Signed-off-by: Yi Liu <yi.l.liu(a)intel.com> Ran the selftests on s390 in both LPAR (z16) and a QEMU kvm guest using 1M hugepages, all tests are passing. Tested-by: Matthew Rosato <mjrosato(a)linux.ibm.com> # s390

2 years, 10 months

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[PATCH] selftests: proc: Fix proc-empty-vm build error on non x86_64

by Punit Agrawal

The proc-empty-vm test is implemented for x86_64 and fails to build for other architectures. Rather then emitting a compiler error it would be preferable to only build the test on supported architectures. Mark proc-empty-vm as a test for x86_64 and customise to the Makefile to build it only when building for this target architecture. Fixes: 5bc73bb3451b ("proc: test how it holds up with mapping'less process") Signed-off-by: Punit Agrawal <punit.agrawal(a)bytedance.com> --- tools/testing/selftests/proc/Makefile | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/proc/Makefile b/tools/testing/selftests/proc/Makefile index cd95369254c0..6b31439902af 100644 --- a/tools/testing/selftests/proc/Makefile +++ b/tools/testing/selftests/proc/Makefile @@ -1,14 +1,18 @@ # SPDX-License-Identifier: GPL-2.0-only + +# When ARCH not overridden for crosscompiling, lookup machine +ARCH ?= $(shell uname -m 2>/dev/null || echo not) + CFLAGS += -Wall -O2 -Wno-unused-function CFLAGS += -D_GNU_SOURCE LDFLAGS += -pthread -TEST_GEN_PROGS := +TEST_GEN_PROGS_x86_64 += proc-empty-vm + TEST_GEN_PROGS += fd-001-lookup TEST_GEN_PROGS += fd-002-posix-eq TEST_GEN_PROGS += fd-003-kthread TEST_GEN_PROGS += proc-loadavg-001 -TEST_GEN_PROGS += proc-empty-vm TEST_GEN_PROGS += proc-pid-vm TEST_GEN_PROGS += proc-self-map-files-001 TEST_GEN_PROGS += proc-self-map-files-002 -- 2.30.2

2 years, 10 months

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[PATCH] selftests/bpf: Fix test_progs compilation failure in 32-bit arch

by Yang Jihong

test_progs fails to be compiled in the 32-bit arch, log is as follows: test_progs.c:1013:52: error: format '%ld' expects argument of type 'long int', but argument 3 has type 'size_t' {aka 'unsigned int'} [-Werror=format=] 1013 | sprintf(buf, "MSG_TEST_LOG (cnt: %ld, last: %d)", | ~~^ | | | long int | %d 1014 | strlen(msg->test_log.log_buf), | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | | | size_t {aka unsigned int} Fix it. Fixes: 91b2c0afd00c ("selftests/bpf: Add parallelism to test_progs") Signed-off-by: Yang Jihong <yangjihong1(a)huawei.com> --- tools/testing/selftests/bpf/test_progs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c index 0e9a47f97890..3fef451d8831 100644 --- a/tools/testing/selftests/bpf/test_progs.c +++ b/tools/testing/selftests/bpf/test_progs.c @@ -1010,7 +1010,7 @@ static inline const char *str_msg(const struct msg *msg, char *buf) msg->subtest_done.have_log); break; case MSG_TEST_LOG: - sprintf(buf, "MSG_TEST_LOG (cnt: %ld, last: %d)", + sprintf(buf, "MSG_TEST_LOG (cnt: %zu, last: %d)", strlen(msg->test_log.log_buf), msg->test_log.is_last); break; -- 2.30.GIT

2 years, 10 months

3
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[PATCH v1 0/6] arm64: Support for 2022 data processing instructions

by Mark Brown

The 2022 update to the Arm architecture includes a number of additions of generic data processing features, covering the base architecture, SVE and SME. Other than SME these are all simple features which introduce no architectural state so we simply need to expose hwcaps for them. This series covers these simple features. Since the SME updates do introduce new architectural state for which we must add new ABI they will be handled in a separate series. Mark Brown (6): arm64/hwcap: Add support for FEAT_CSSC kselftest/arm64: Add FEAT_CSSC to the hwcap selftest arm64/hwcap: Add support for FEAT_RPRFM kselftest/arm64: Add FEAT_RPRFM to the hwcap test arm64/hwcap: Add support for SVE 2.1 kselftest/arm64: Add SVE 2.1 to hwcap test Documentation/arm64/elf_hwcaps.rst | 9 +++++++ Documentation/arm64/sve.rst | 1 + arch/arm64/include/asm/hwcap.h | 3 +++ arch/arm64/include/uapi/asm/hwcap.h | 3 +++ arch/arm64/kernel/cpufeature.c | 5 ++++ arch/arm64/kernel/cpuinfo.c | 3 +++ arch/arm64/tools/sysreg | 12 ++++++++- tools/testing/selftests/arm64/abi/hwcap.c | 32 +++++++++++++++++++++++ 8 files changed, 67 insertions(+), 1 deletion(-) base-commit: 9abf2313adc1ca1b6180c508c25f22f9395cc780 -- 2.30.2

2 years, 10 months

3
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[RFC PATCH v1 0/2] Fix offset when fault occurs in strncpy_from_kernel_nofault()

by Francis Laniel

Hi. First of all, I hope you are fine and the same for your relatives. This contribution fixes a bug where the byte before the destination address can be reset when a page fault occurs in strncpy_from_kernel_nofault() while copying the first byte from the source address. This bug leaded to kernel panic if a pointer containing the modified address is dereferenced as the pointer does not contain a correct addresss. To fix this bug, we simply reset the current destination byte in a case of a page fault. The proposed fix was tested and validated inside a VM: root@vm-amd64:~# ./share/linux/tools/testing/selftests/bpf/test_progs --name varlen ... #222 varlen:OK Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED Without the patch, the test will fail: root@vm-amd64:~# ./share/linux/tools/testing/selftests/bpf/test_progs --name varlen ... #222 varlen:FAIL Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED If you see any way to improve this contribution, feel free to share. Alban Crequy (2): maccess: fix writing offset in case of fault in strncpy_from_kernel_nofault() selftests: bpf: add a test when bpf_probe_read_kernel_str() returns EFAULT mm/maccess.c | 2 +- tools/testing/selftests/bpf/prog_tests/varlen.c | 7 +++++++ tools/testing/selftests/bpf/progs/test_varlen.c | 5 +++++ 3 files changed, 13 insertions(+), 1 deletion(-) Best regards and thank you in advance. -- 2.25.1

2 years, 10 months

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