6.8-stable review patch. If anyone has any objections, please let me know.
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From: Nathan Chancellor nathan@kernel.org
commit f7d5bcd35d427daac7e206b1073ca14f5db85c27 upstream.
After commit 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()"), clang warns:
tools/testing/selftests/timers/../kselftest.h:398:6: warning: variable 'major' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized] 398 | if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2) | ^~~~~~~~~~~~ tools/testing/selftests/timers/../kselftest.h:401:9: note: uninitialized use occurs here 401 | return major > min_major || (major == min_major && minor >= min_minor); | ^~~~~ tools/testing/selftests/timers/../kselftest.h:398:6: note: remove the '||' if its condition is always false 398 | if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2) | ^~~~~~~~~~~~~~~ tools/testing/selftests/timers/../kselftest.h:395:20: note: initialize the variable 'major' to silence this warning 395 | unsigned int major, minor; | ^ | = 0
This is a false positive because if uname() fails, ksft_exit_fail_msg() will be called, which unconditionally calls exit(), a noreturn function. However, clang does not know that ksft_exit_fail_msg() will call exit() at the point in the pipeline that the warning is emitted because inlining has not occurred, so it assumes control flow will resume normally after ksft_exit_fail_msg() is called.
Make it clear to clang that all of the functions that call exit() unconditionally in kselftest.h are noreturn transitively by marking them explicitly with '__attribute__((__noreturn__))', which clears up the warning above and any future warnings that may appear for the same reason.
Fixes: 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()") Reported-by: John Stultz jstultz@google.com Signed-off-by: Nathan Chancellor nathan@kernel.org Signed-off-by: Thomas Gleixner tglx@linutronix.de Acked-by: Shuah Khan skhan@linuxfoundation.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240411-mark-kselftest-exit-funcs-noreturn-v1-1-b... Closes: https://lore.kernel.org/all/20240410232637.4135564-2-jstultz@google.com/ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/kselftest.h | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
--- a/tools/testing/selftests/kselftest.h +++ b/tools/testing/selftests/kselftest.h @@ -79,6 +79,9 @@ #define KSFT_XPASS 3 #define KSFT_SKIP 4
+#ifndef __noreturn +#define __noreturn __attribute__((__noreturn__)) +#endif #define __printf(a, b) __attribute__((format(printf, a, b)))
/* counters */ @@ -255,13 +258,13 @@ static inline __printf(1, 2) void ksft_t va_end(args); }
-static inline int ksft_exit_pass(void) +static inline __noreturn int ksft_exit_pass(void) { ksft_print_cnts(); exit(KSFT_PASS); }
-static inline int ksft_exit_fail(void) +static inline __noreturn int ksft_exit_fail(void) { ksft_print_cnts(); exit(KSFT_FAIL); @@ -288,7 +291,7 @@ static inline int ksft_exit_fail(void) ksft_cnt.ksft_xfail + \ ksft_cnt.ksft_xskip)
-static inline __printf(1, 2) int ksft_exit_fail_msg(const char *msg, ...) +static inline __noreturn __printf(1, 2) int ksft_exit_fail_msg(const char *msg, ...) { int saved_errno = errno; va_list args; @@ -303,19 +306,19 @@ static inline __printf(1, 2) int ksft_ex exit(KSFT_FAIL); }
-static inline int ksft_exit_xfail(void) +static inline __noreturn int ksft_exit_xfail(void) { ksft_print_cnts(); exit(KSFT_XFAIL); }
-static inline int ksft_exit_xpass(void) +static inline __noreturn int ksft_exit_xpass(void) { ksft_print_cnts(); exit(KSFT_XPASS); }
-static inline __printf(1, 2) int ksft_exit_skip(const char *msg, ...) +static inline __noreturn __printf(1, 2) int ksft_exit_skip(const char *msg, ...) { int saved_errno = errno; va_list args;