May 2024 - Linux-kselftest-mirror

[PATCH] selftests: filesystems: fix warn_unused_result build warnings

by Amer Al Shanawany

Fix the following warnings by adding return check and error messages. statmount_test.c: In function ‘cleanup_namespace’: statmount_test.c:128:9: warning: ignoring return value of ‘fchdir’ declared with attribute ‘warn_unused_result’ [-Wunused-result] 128 | fchdir(orig_root); | ^~~~~~~~~~~~~~~~~ statmount_test.c:129:9: warning: ignoring return value of ‘chroot’ declared with attribute ‘warn_unused_result’ [-Wunused-result] 129 | chroot("."); | ^~~~~~~~~~~ Signed-off-by: Amer Al Shanawany <amer.shanawany(a)gmail.com> --- .../selftests/filesystems/statmount/statmount_test.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/filesystems/statmount/statmount_test.c b/tools/testing/selftests/filesystems/statmount/statmount_test.c index e6d7c4f1c85b..e8c019d72cbf 100644 --- a/tools/testing/selftests/filesystems/statmount/statmount_test.c +++ b/tools/testing/selftests/filesystems/statmount/statmount_test.c @@ -125,8 +125,16 @@ static uint32_t old_root_id, old_parent_id; static void cleanup_namespace(void) { - fchdir(orig_root); - chroot("."); + int ret; + + ret = fchdir(orig_root); + if (ret == -1) + ksft_perror("fchdir to original root"); + + ret = chroot("."); + if (ret == -1) + ksft_perror("chroot to original root"); + umount2(root_mntpoint, MNT_DETACH); rmdir(root_mntpoint); } -- 2.34.1

6 months, 2 weeks

3
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[PATCH v4 00/10] Add support for synchronous signals on perf events

by Marco Elver

The perf subsystem today unifies various tracing and monitoring features, from both software and hardware. One benefit of the perf subsystem is automatically inheriting events to child tasks, which enables process-wide events monitoring with low overheads. By default perf events are non-intrusive, not affecting behaviour of the tasks being monitored. For certain use-cases, however, it makes sense to leverage the generality of the perf events subsystem and optionally allow the tasks being monitored to receive signals on events they are interested in. This patch series adds the option to synchronously signal user space on events. To better support process-wide synchronous self-monitoring, without events propagating to children that do not share the current process's shared environment, two pre-requisite patches are added to optionally restrict inheritance to CLONE_THREAD, and remove events on exec (without affecting the parent). Examples how to use these features can be found in the tests added at the end of the series. In addition to the tests added, the series has also been subjected to syzkaller fuzzing (focus on 'kernel/events/' coverage). Motivation and Example Uses --------------------------- 1. Our immediate motivation is low-overhead sampling-based race detection for user space [1]. By using perf_event_open() at process initialization, we can create hardware breakpoint/watchpoint events that are propagated automatically to all threads in a process. As far as we are aware, today no existing kernel facility (such as ptrace) allows us to set up process-wide watchpoints with minimal overheads (that are comparable to mprotect() of whole pages). 2. Other low-overhead error detectors that rely on detecting accesses to certain memory locations or code, process-wide and also only in a specific set of subtasks or threads. [1] https://llvm.org/devmtg/2020-09/slides/Morehouse-GWP-Tsan.pdf Other ideas for use-cases we found interesting, but should only illustrate the range of potential to further motivate the utility (we're sure there are more): 3. Code hot patching without full stop-the-world. Specifically, by setting a code breakpoint to entry to the patched routine, then send signals to threads and check that they are not in the routine, but without stopping them further. If any of the threads will enter the routine, it will receive SIGTRAP and pause. 4. Safepoints without mprotect(). Some Java implementations use "load from a known memory location" as a safepoint. When threads need to be stopped, the page containing the location is mprotect()ed and threads get a signal. This could be replaced with a watchpoint, which does not require a whole page nor DTLB shootdowns. 5. Threads receiving signals on performance events to throttle/unthrottle themselves. 6. Tracking data flow globally. Changelog --------- v4: * Fix for parent and child racing to exit in sync_child_event(). * Fix race between irq_work running and task's sighand being released by release_task(). * Generalize setting si_perf and si_addr independent of event type; introduces perf_event_attr::sig_data, which can be set by user space to be propagated to si_perf. * Warning in perf_sigtrap() if ctx->task and current mismatch; we expect this on architectures that do not properly implement arch_irq_work_raise(). * Require events that want sigtrap to be associated with a task. * Dropped "perf: Add breakpoint information to siginfo on SIGTRAP" in favor of more generic solution (perf_event_attr::sig_data). v3: * Add patch "perf: Rework perf_event_exit_event()" to beginning of series, courtesy of Peter Zijlstra. * Rework "perf: Add support for event removal on exec" based on the added "perf: Rework perf_event_exit_event()". * Fix kselftests to work with more recent libc, due to the way it forces using the kernel's own siginfo_t. * Add basic perf-tool built-in test. v2/RFC: https://lkml.kernel.org/r/20210310104139.679618-1-elver@google.com * Patch "Support only inheriting events if cloned with CLONE_THREAD" added to series. * Patch "Add support for event removal on exec" added to series. * Patch "Add kselftest for process-wide sigtrap handling" added to series. * Patch "Add kselftest for remove_on_exec" added to series. * Implicitly restrict inheriting events if sigtrap, but the child was cloned with CLONE_CLEAR_SIGHAND, because it is not generally safe if the child cleared all signal handlers to continue sending SIGTRAP. * Various minor fixes (see details in patches). v1/RFC: https://lkml.kernel.org/r/20210223143426.2412737-1-elver@google.com Pre-series: The discussion at [2] led to the changes in this series. The approach taken in "Add support for SIGTRAP on perf events" to trigger the signal was suggested by Peter Zijlstra in [3]. [2] https://lore.kernel.org/lkml/CACT4Y+YPrXGw+AtESxAgPyZ84TYkNZdP0xpocX2jwVAbZ… [3] https://lore.kernel.org/lkml/YBv3rAT566k+6zjg@hirez.programming.kicks-ass.n… Marco Elver (9): perf: Apply PERF_EVENT_IOC_MODIFY_ATTRIBUTES to children perf: Support only inheriting events if cloned with CLONE_THREAD perf: Add support for event removal on exec signal: Introduce TRAP_PERF si_code and si_perf to siginfo perf: Add support for SIGTRAP on perf events selftests/perf_events: Add kselftest for process-wide sigtrap handling selftests/perf_events: Add kselftest for remove_on_exec tools headers uapi: Sync tools/include/uapi/linux/perf_event.h perf test: Add basic stress test for sigtrap handling Peter Zijlstra (1): perf: Rework perf_event_exit_event() arch/m68k/kernel/signal.c | 3 + arch/x86/kernel/signal_compat.c | 5 +- fs/signalfd.c | 4 + include/linux/compat.h | 2 + include/linux/perf_event.h | 9 +- include/linux/signal.h | 1 + include/uapi/asm-generic/siginfo.h | 6 +- include/uapi/linux/perf_event.h | 12 +- include/uapi/linux/signalfd.h | 4 +- kernel/events/core.c | 302 +++++++++++++----- kernel/fork.c | 2 +- kernel/signal.c | 11 + tools/include/uapi/linux/perf_event.h | 12 +- tools/perf/tests/Build | 1 + tools/perf/tests/builtin-test.c | 5 + tools/perf/tests/sigtrap.c | 150 +++++++++ tools/perf/tests/tests.h | 1 + .../testing/selftests/perf_events/.gitignore | 3 + tools/testing/selftests/perf_events/Makefile | 6 + tools/testing/selftests/perf_events/config | 1 + .../selftests/perf_events/remove_on_exec.c | 260 +++++++++++++++ tools/testing/selftests/perf_events/settings | 1 + .../selftests/perf_events/sigtrap_threads.c | 210 ++++++++++++ 23 files changed, 924 insertions(+), 87 deletions(-) create mode 100644 tools/perf/tests/sigtrap.c create mode 100644 tools/testing/selftests/perf_events/.gitignore create mode 100644 tools/testing/selftests/perf_events/Makefile create mode 100644 tools/testing/selftests/perf_events/config create mode 100644 tools/testing/selftests/perf_events/remove_on_exec.c create mode 100644 tools/testing/selftests/perf_events/settings create mode 100644 tools/testing/selftests/perf_events/sigtrap_threads.c -- 2.31.0.208.g409f899ff0-goog

6 months, 2 weeks

5
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[PATCH bpf-next] selftests/bpf: Enable INET_XFRM_TUNNEL in config

by Geliang Tang

From: Geliang Tang <tanggeliang(a)kylinos.cn> The kconfigs CONFIG_INET_XFRM_TUNNEL and CONFIG_INET6_XFRM_TUNNEL are needed by test_tunnel tests. This patch enables them together with the dependent kconfigs CONFIG_INET_IPCOMP and CONFIG_INET6_IPCOMP. Signed-off-by: Geliang Tang <tanggeliang(a)kylinos.cn> --- tools/testing/selftests/bpf/config | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config index eeabd798bc3a..8aa56e6bdac1 100644 --- a/tools/testing/selftests/bpf/config +++ b/tools/testing/selftests/bpf/config @@ -95,3 +95,7 @@ CONFIG_XDP_SOCKETS=y CONFIG_XFRM_INTERFACE=y CONFIG_TCP_CONG_DCTCP=y CONFIG_TCP_CONG_BBR=y +CONFIG_INET_IPCOMP=y +CONFIG_INET_XFRM_TUNNEL=y +CONFIG_INET6_IPCOMP=y +CONFIG_INET6_XFRM_TUNNEL=y -- 2.43.0

6 months, 2 weeks

3
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[PATCH 0/2] usercopy: Convert test_user_copy to KUnit test

by Kees Cook

Hi, This builds on the proposal[1] from Mark and lets me convert the existing usercopy selftest to KUnit. Besides adding this basic test to the KUnit collection, it also opens the door for execve testing (which depends on having a functional current->mm), and should provide the basic infrastructure for adding Mark's much more complete usercopy tests. -Kees [1] https://lore.kernel.org/lkml/20230321122514.1743889-2-mark.rutland@arm.com/ Kees Cook (2): kunit: test: Add vm_mmap() allocation resource manager usercopy: Convert test_user_copy to KUnit test MAINTAINERS | 1 + include/kunit/test.h | 17 ++ lib/Kconfig.debug | 21 +- lib/Makefile | 2 +- lib/kunit/test.c | 139 +++++++++++- lib/{test_user_copy.c => usercopy_kunit.c} | 252 ++++++++++----------- 6 files changed, 288 insertions(+), 144 deletions(-) rename lib/{test_user_copy.c => usercopy_kunit.c} (52%) -- 2.34.1

6 months, 2 weeks

5
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[PATCH 0/8] selftests: x86: build suite with clang

by Muhammad Usama Anjum

This series fixes build errors found by clang to allow the x86 suite to get built with the clang. Unfortunately, there is one bug [1] in the clang becuase of which extended asm isn't handled correctly by it and build fails for sysret_rip.c. Hence even after this series the build of this test would fail with clang. Should we disable this test for now when clang is used until the bug is fixed in clang? Not sure. Any opinions? [1] https://github.com/llvm/llvm-project/issues/53728 Muhammad Usama Anjum (8): selftests: x86: Remove dependence of headers file selftests: x86: check_initial_reg_state: remove -no-pie while using -static selftests: x86: test_vsyscall: remove unused function selftests: x86: fsgsbase_restore: fix asm directive from =rm to =r selftests: x86: syscall_arg_fault_32: remove unused variable selftests: x86: test_FISTTP: use fisttps instead of ambigous fisttp selftests: x86: fsgsbase: Remove unused function and variable selftests: x86: amx: Remove unused functions tools/testing/selftests/x86/Makefile | 9 +++++---- tools/testing/selftests/x86/amx.c | 16 ---------------- tools/testing/selftests/x86/fsgsbase.c | 6 ------ tools/testing/selftests/x86/fsgsbase_restore.c | 2 +- tools/testing/selftests/x86/syscall_arg_fault.c | 1 - tools/testing/selftests/x86/test_FISTTP.c | 8 ++++---- tools/testing/selftests/x86/test_vsyscall.c | 5 ----- 7 files changed, 10 insertions(+), 37 deletions(-) -- 2.39.2

6 months, 2 weeks

5
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[PATCH] tools/testing/selftests/x86: add dlclose function in the vdso_restorer.c

by liujing

in the main function of vdso_restorer.c,there is a dlopen function, but there is no dlclose function to close the file Signed-off-by: liujing <liujing(a)cmss.chinamobile.com> --- tools/testing/selftests/x86/vdso_restorer.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/selftests/x86/vdso_restorer.c b/tools/testing/selftests/x86/vdso_restorer.c index fe99f2434155..a0b1155dee31 100644 --- a/tools/testing/selftests/x86/vdso_restorer.c +++ b/tools/testing/selftests/x86/vdso_restorer.c @@ -57,6 +57,8 @@ int main() return 0; } + dlclose(vdso); + memset(&sa, 0, sizeof(sa)); sa.handler = handler_with_siginfo; sa.flags = SA_SIGINFO; -- 2.18.2

6 months, 2 weeks

2
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[PATCH 0/4] kselftests: vdso: conform tests to TAP output

by Muhammad Usama Anjum

Conform individual tests to TAP output. One patch conform one test. With this series, all vDSO tests become TAP conformant. Muhammad Usama Anjum (4): kselftests: vdso: vdso_test_clock_getres: conform test to TAP output kselftests: vdso: vdso_test_correctness: conform test to TAP output kselftests: vdso: vdso_test_getcpu: conform test to TAP output kselftests: vdso: vdso_test_gettimeofday: conform test to TAP output .../selftests/vDSO/vdso_test_clock_getres.c | 68 ++++---- .../selftests/vDSO/vdso_test_correctness.c | 146 +++++++++--------- .../testing/selftests/vDSO/vdso_test_getcpu.c | 16 +- .../selftests/vDSO/vdso_test_gettimeofday.c | 23 +-- 4 files changed, 126 insertions(+), 127 deletions(-) -- 2.39.2

6 months, 2 weeks

2
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[PATCH v2 0/2] selftests/lib.mk: LLVM=1, CC=clang, and warnings

by John Hubbard

The kselftests may be built in a couple different ways: make LLVM=1 make CC=clang In order to handle both cases, set LLVM=1 if CC=clang. That way,the rest of lib.mk, and any Makefiles that include lib.mk, can base decisions solely on whether or not LLVM is set. Then, build upon that to disable a pair of clang warnings that are already silenced on gcc. Doing it this way is much better than the piecemeal approach that I started with in [1] and [2]. Thanks to Nathan Chancellor for the patch reviews that led to this approach. Changes since the first version: 1) Wrote a detailed explanation for suppressing two clang warnings, in both a lib.mk comment, and the commit description. 2) Added a Reviewed-by tag to the first patch. [1] https://lore.kernel.org/20240527214704.300444-1-jhubbard@nvidia.com [2] https://lore.kernel.org/20240527213641.299458-1-jhubbard@nvidia.com John Hubbard (2): selftests/lib.mk: handle both LLVM=1 and CC=clang builds selftests/lib.mk: silence some clang warnings that gcc already ignores tools/testing/selftests/lib.mk | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) base-commit: e0cce98fe279b64f4a7d81b7f5c3a23d80b92fbc -- 2.45.1

6 months, 2 weeks

5
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[PATCH v2 0/2] memfd: fix MFD_NOEXEC_SEAL to be non-sealable

by jeffxu＠chromium.org

From: Jeff Xu <jeffxu(a)google.com> By default, memfd_create() creates a non-sealable MFD, unless the MFD_ALLOW_SEALING flag is set. When the MFD_NOEXEC_SEAL flag is initially introduced, the MFD created with that flag is sealable, even though MFD_ALLOW_SEALING is not set. This patch changes MFD_NOEXEC_SEAL to be non-sealable by default, unless MFD_ALLOW_SEALING is explicitly set. This is a non-backward compatible change. However, as MFD_NOEXEC_SEAL is new, we expect not many applications will rely on the nature of MFD_NOEXEC_SEAL being sealable. In most cases, the application already sets MFD_ALLOW_SEALING if they need a sealable MFD. Additionally, this enhances the useability of pid namespace sysctl vm.memfd_noexec. When vm.memfd_noexec equals 1 or 2, the kernel will add MFD_NOEXEC_SEAL if mfd_create does not specify MFD_EXEC or MFD_NOEXEC_SEAL, and the addition of MFD_NOEXEC_SEAL enables the MFD to be sealable. This means, any application that does not desire this behavior will be unable to utilize vm.memfd_noexec = 1 or 2 to migrate/enforce non-executable MFD. This adjustment ensures that applications can anticipate that the sealable characteristic will remain unmodified by vm.memfd_noexec. This patch was initially developed by Barnabás Pőcze, and Barnabás used Debian Code Search and GitHub to try to find potential breakages and could only find a single one. Dbus-broker's memfd_create() wrapper is aware of this implicit `MFD_ALLOW_SEALING` behavior, and tries to work around it [1]. This workaround will break. Luckily, this only affects the test suite, it does not affect the normal operations of dbus-broker. There is a PR with a fix[2]. In addition, David Rheinsberg also raised similar fix in [3] [1]: https://github.com/bus1/dbus-broker/blob/9eb0b7e5826fc76cad7b025bc46f267d4a… [2]: https://github.com/bus1/dbus-broker/pull/366 [3]: https://lore.kernel.org/lkml/20230714114753.170814-1-david@readahead.eu/ History ====== V2: update commit message. add testcase for vm.memfd_noexec add documentation. V1: https://lore.kernel.org/lkml/20240513191544.94754-1-pobrn@protonmail.com/ Jeff Xu (2): memfd: fix MFD_NOEXEC_SEAL to be non-sealable by default memfd:add MEMFD_NOEXEC_SEAL documentation Documentation/userspace-api/index.rst | 1 + Documentation/userspace-api/mfd_noexec.rst | 90 ++++++++++++++++++++++ mm/memfd.c | 9 +-- tools/testing/selftests/memfd/memfd_test.c | 26 ++++++- 4 files changed, 120 insertions(+), 6 deletions(-) create mode 100644 Documentation/userspace-api/mfd_noexec.rst -- 2.45.1.288.g0e0cd299f1-goog

6 months, 2 weeks

5
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[PATCH v1] memfd: `MFD_NOEXEC_SEAL` should not imply `MFD_ALLOW_SEALING`

by Barnabás Pőcze

`MFD_NOEXEC_SEAL` should remove the executable bits and set `F_SEAL_EXEC` to prevent further modifications to the executable bits as per the comment in the uapi header file: not executable and sealed to prevent changing to executable However, currently, it also unsets `F_SEAL_SEAL`, essentially acting as a superset of `MFD_ALLOW_SEALING`. Nothing implies that it should be so, and indeed up until the second version of the of the patchset[0] that introduced `MFD_EXEC` and `MFD_NOEXEC_SEAL`, `F_SEAL_SEAL` was not removed, however it was changed in the third revision of the patchset[1] without a clear explanation. This behaviour is suprising for application developers, there is no documentation that would reveal that `MFD_NOEXEC_SEAL` has the additional effect of `MFD_ALLOW_SEALING`. So do not remove `F_SEAL_SEAL` when `MFD_NOEXEC_SEAL` is requested. This is technically an ABI break, but it seems very unlikely that an application would depend on this behaviour (unless by accident). [0]: https://lore.kernel.org/lkml/20220805222126.142525-3-jeffxu@google.com/ [1]: https://lore.kernel.org/lkml/20221202013404.163143-3-jeffxu@google.com/ Fixes: 105ff5339f498a ("mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC") Signed-off-by: Barnabás Pőcze <pobrn(a)protonmail.com> --- Or did I miss the explanation as to why MFD_NOEXEC_SEAL should imply MFD_ALLOW_SEALING? If so, please direct me to it and sorry for the noise. --- mm/memfd.c | 9 ++++----- tools/testing/selftests/memfd/memfd_test.c | 2 +- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/mm/memfd.c b/mm/memfd.c index 7d8d3ab3fa37..8b7f6afee21d 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -356,12 +356,11 @@ SYSCALL_DEFINE2(memfd_create, inode->i_mode &= ~0111; file_seals = memfd_file_seals_ptr(file); - if (file_seals) { - *file_seals &= ~F_SEAL_SEAL; + if (file_seals) *file_seals |= F_SEAL_EXEC; - } - } else if (flags & MFD_ALLOW_SEALING) { - /* MFD_EXEC and MFD_ALLOW_SEALING are set */ + } + + if (flags & MFD_ALLOW_SEALING) { file_seals = memfd_file_seals_ptr(file); if (file_seals) *file_seals &= ~F_SEAL_SEAL; diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c index 18f585684e20..b6a7ad68c3c1 100644 --- a/tools/testing/selftests/memfd/memfd_test.c +++ b/tools/testing/selftests/memfd/memfd_test.c @@ -1151,7 +1151,7 @@ static void test_noexec_seal(void) mfd_def_size, MFD_CLOEXEC | MFD_NOEXEC_SEAL); mfd_assert_mode(fd, 0666); - mfd_assert_has_seals(fd, F_SEAL_EXEC); + mfd_assert_has_seals(fd, F_SEAL_SEAL | F_SEAL_EXEC); mfd_fail_chmod(fd, 0777); close(fd); } -- 2.45.0

6 months, 2 weeks

6
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