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selftests: kselftest: Mark functions that unconditionally call exit() as __noreturn

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After commit 6d029c25b7 ("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: 6d029c25b7 ("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-b027c948f586@kernel.org
Closes: https://lore.kernel.org/all/20240410232637.4135564-2-jstultz@google.com/
This commit is contained in:
Nathan Chancellor 2024-04-11 11:45:40 -07:00 committed by Thomas Gleixner
parent e4a6bceac9
commit f7d5bcd35d
1 changed files with 9 additions and 6 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

15
tools/testing/selftests/kselftest.h
View file

@ -80,6 +80,9 @@
#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 */
@ -300,13 +303,13 @@ void ksft_test_result_code(int exit_code, const char *test_name,
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);
@ -333,7 +336,7 @@ 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;
@ -348,19 +351,19 @@ static inline __printf(1, 2) int ksft_exit_fail_msg(const char *msg, ...)
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;