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author | Mickaël Salaün <mic@digikod.net> | 2024-05-11 19:14:39 +0200 |
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committer | Mickaël Salaün <mic@digikod.net> | 2024-05-11 19:18:43 +0200 |
commit | a86f18903db9211e265cc130b61adb175b7a4c42 (patch) | |
tree | 1d9d85b73e87ef40e5371022331b872cf3c0579b | |
parent | fff37bd32c7605d93bf900c4c318d56d12000048 (diff) | |
download | linux-stable-a86f18903db9211e265cc130b61adb175b7a4c42.tar.gz linux-stable-a86f18903db9211e265cc130b61adb175b7a4c42.tar.bz2 linux-stable-a86f18903db9211e265cc130b61adb175b7a4c42.zip |
selftests/harness: Fix interleaved scheduling leading to race conditions
Fix a race condition when running several FIXTURE_TEARDOWN() managing
the same resource. This fixes a race condition in the Landlock file
system tests when creating or unmounting the same directory.
Using clone3() with CLONE_VFORK guarantees that the child and grandchild
test processes are sequentially scheduled. This is implemented with a
new clone3_vfork() helper replacing the fork() call.
This avoids triggering this error in __wait_for_test():
Test ended in some other way [127]
Cc: Christian Brauner <brauner@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Günther Noack <gnoack@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Will Drewry <wad@chromium.org>
Fixes: 41cca0542d7c ("selftests/harness: Fix TEST_F()'s vfork handling")
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240511171445.904356-5-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
-rw-r--r-- | tools/testing/selftests/kselftest_harness.h | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h index 55699a762c45..9d7178a71c2c 100644 --- a/tools/testing/selftests/kselftest_harness.h +++ b/tools/testing/selftests/kselftest_harness.h @@ -66,6 +66,8 @@ #include <sys/wait.h> #include <unistd.h> #include <setjmp.h> +#include <syscall.h> +#include <linux/sched.h> #include "kselftest.h" @@ -80,6 +82,17 @@ # define TH_LOG_ENABLED 1 #endif +/* Wait for the child process to end but without sharing memory mapping. */ +static inline pid_t clone3_vfork(void) +{ + struct clone_args args = { + .flags = CLONE_VFORK, + .exit_signal = SIGCHLD, + }; + + return syscall(__NR_clone3, &args, sizeof(args)); +} + /** * TH_LOG() * @@ -1183,7 +1196,7 @@ void __run_test(struct __fixture_metadata *f, fflush(stdout); fflush(stderr); - t->pid = fork(); + t->pid = clone3_vfork(); if (t->pid < 0) { ksft_print_msg("ERROR SPAWNING TEST CHILD\n"); t->exit_code = KSFT_FAIL; |