selftests: timers: Fix posix_timers ksft_print_msg warning

PATCH Applied John Stultz 6 participants 13 messages Apr 10, 2024 – Apr 12, 2024

Subsystems (4)

Stable branch Kselftest Timekeeping, clocksource core, NTP, alarmtimer High-resolution timers, timer wheel, clockevents

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John Stultz

author maintainer

2024-04-10 23:26 UTC #0 lore raw

PATCH 1/3 selftests: timers: Fix posix_timers ksft_print_msg warning

After commit 6d029c25b71f ("selftests/timers/posix_timers:
Reimplement check_timer_distribution()") I started seeing the following warning building with an older gcc:

posix_timers.c:250:2: warning: format not a string literal and no format arguments [-Wformat-security]

  250 |  ksft_print_msg(errmsg);
      |  ^~~~~~~~~~~~~~

Fix this up by changing it to ksft_print_msg("%s", errmsg)

Cc Shuah Khan <[email protected]>

Cc Anna-Maria Behnsen <[email protected]>

Cc Frederic Weisbecker <[email protected]>

Cc Thomas Gleixner <[email protected]>

Cc Stephen Boyd <[email protected]>

Cc Nathan Chancellor <[email protected]>

Cc Nick Desaulniers <[email protected]>

Cc Bill Wendling <[email protected]>

Cc Justin Stitt <[email protected]>

Cc Oleg Nesterov <[email protected]>

Cc Andrew Morton <[email protected]>

Cc Edward Liaw <[email protected]>

Cc Carlos Llamas <[email protected]>

Cc [email protected]

Fixes 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()")

Signed-off-by John Stultz <[email protected]>

---
 tools/testing/selftests/timers/posix_timers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

tools/testing/selftests/timers/posix_timers.c +1 -1

index d86a0e00711e..348f47176e0a 100644
@@ -247,7 +247,7 @@ static int check_timer_distribution(void)
 		ksft_test_result_skip("check signal distribution (old kernel)\n");
 	return 0;
 err:
-	ksft_print_msg(errmsg);
+	ksft_print_msg("%s", errmsg);
 	return -1;
 }

Signature · 1 line

2.44.0.478.gd926399ef9-goog

John Stultz

author maintainer

2024-04-10 23:26 UTC #1 lore raw

PATCH 2/3 selftests: timers: Fix uninitialized variable warning in ksft_min_kernel_version

Building with clang, I see the following warning:

In file included from posix_timers.c:17:
./../kselftest.h:398:6: warning: variable 'major' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized]

        if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2)
            ^~~~~~~~~~~~
./../kselftest.h:401:9: note: uninitialized use occurs here
        return major > min_major || (major == min_major && minor >= min_minor);
               ^~~~~

This is a bit of a red-herring as if the uname() call did fail, we would hit ksft_exit_fail_msg() which should exit.

But to make clang happpy, lets initialize the major/minor values to zero.

Cc Shuah Khan <[email protected]>

Cc Anna-Maria Behnsen <[email protected]>

Cc Frederic Weisbecker <[email protected]>

Cc Thomas Gleixner <[email protected]>

Cc Stephen Boyd <[email protected]>

Cc Nathan Chancellor <[email protected]>

Cc Nick Desaulniers <[email protected]>

Cc Bill Wendling <[email protected]>

Cc Justin Stitt <[email protected]>

Cc Oleg Nesterov <[email protected]>

Cc Andrew Morton <[email protected]>

Cc Edward Liaw <[email protected]>

Cc Carlos Llamas <[email protected]>

Cc [email protected]

Fixes 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()")

Signed-off-by John Stultz <[email protected]>

---
 tools/testing/selftests/kselftest.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

tools/testing/selftests/kselftest.h +1 -1

index 973b18e156b2..12e2f3ab8b13 100644
@@ -392,7 +392,7 @@ static inline __printf(1, 2) int ksft_exit_skip(const char *msg, ...)
 static inline int ksft_min_kernel_version(unsigned int min_major,
 					  unsigned int min_minor)
 {
-	unsigned int major, minor;
+	unsigned int major = 0, minor = 0;
 	struct utsname info;
 
 	if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2)

Signature · 1 line

2.44.0.478.gd926399ef9-goog

Nathan Chancellor

2024-04-11 15:39 UTC #2 lore raw

Re: [PATCH 2/3] selftests: timers: Fix uninitialized variable warning in ksft_min_kernel_version

Quoted 4 lines · John Stultz

Building with clang, I see the following warning:
In file included from posix_timers.c:17:
./../kselftest.h:398:6: warning: variable 'major' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized]

Quoted 8 lines

        if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2)
            ^~~~~~~~~~~~
./../kselftest.h:401:9: note: uninitialized use occurs here
        return major > min_major || (major == min_major && minor >= min_minor);
               ^~~~~

This is a bit of a red-herring as if the uname() call did fail, we would hit ksft_exit_fail_msg() which should exit.

Correct, although we have not really conveyed that to the compiler, right? exit() is noreturn, which means all functions that call exit() unconditionally are also noreturn, such as ksft_exit_fail_msg(). LLVM will figure this out once it performs inlining and such but that happens after clang's static analysis phase that this warning occurs in. I think a better solution would be to add __noreturn to the functions in tools/testing/selftests/kselftest.h that call exit(), so that the compiler is aware of this through all pipeline phases, maybe something like this? It resolves the wawrning for me.

tools/testing/selftests/kselftest.h +8 -7

index 050c5fd01840..29364c9f3332 100644
@@ -83,6 +83,7 @@
 #define KSFT_XPASS 3
 #define KSFT_SKIP  4
 
+#define __noreturn       __attribute__((__noreturn__))
 #define __printf(a, b)   __attribute__((format(printf, a, b)))
 
 /* counters */

@@ -324,13 +325,13 @@ void ksft_test_result_code(int exit_code, const char *test_name,
 		break;						\
 	} } while (0)
 
-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);

@@ -357,7 +358,7 @@ 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;

@@ -372,7 +373,7 @@ static inline __printf(1, 2) int ksft_exit_fail_msg(const char *msg, ...)
 	exit(KSFT_FAIL);
 }
 
-static inline void ksft_exit_fail_perror(const char *msg)
+static inline __noreturn void ksft_exit_fail_perror(const char *msg)
 {
 #ifndef NOLIBC
 	ksft_exit_fail_msg("%s: %s (%d)\n", msg, strerror(errno), errno);

@@ -385,19 +386,19 @@ static inline void ksft_exit_fail_perror(const char *msg)
 #endif
 }
 
-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;

John Stultz

author maintainer

2024-04-11 18:12 UTC #3 lore raw

Re: [PATCH 2/3] selftests: timers: Fix uninitialized variable warning in ksft_min_kernel_version

Quoted 14 lines · Nathan Chancellor

Quoted 4 lines · John Stultz
Building with clang, I see the following warning:
In file included from posix_timers.c:17:
./../kselftest.h:398:6: warning: variable 'major' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized]
Quoted 8 lines
        if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2)
            ^~~~~~~~~~~~
./../kselftest.h:401:9: note: uninitialized use occurs here
        return major > min_major || (major == min_major && minor >= min_minor);
               ^~~~~
This is a bit of a red-herring as if the uname() call did fail, we would hit ksft_exit_fail_msg() which should exit.

Quoted 9 lines

Correct, although we have not really conveyed that to the compiler, right? exit() is noreturn, which means all functions that call exit() unconditionally are also noreturn, such as ksft_exit_fail_msg(). LLVM will figure this out once it performs inlining and such but that happens after clang's static analysis phase that this warning occurs in. I think a better solution would be to add __noreturn to the functions in tools/testing/selftests/kselftest.h that call exit(), so that the compiler is aware of this through all pipeline phases, maybe something like this? It resolves the wawrning for me.

No objection from me if this is the better approach.

Would you send that patch out?

thanks
-john

Nathan Chancellor

2024-04-11 18:47 UTC #4 lore raw

Re: [PATCH 2/3] selftests: timers: Fix uninitialized variable warning in ksft_min_kernel_version

Quoted 25 lines · John Stultz

Quoted 14 lines · Nathan Chancellor
Quoted 4 lines · John Stultz
Building with clang, I see the following warning:
In file included from posix_timers.c:17:
./../kselftest.h:398:6: warning: variable 'major' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized]
Quoted 8 lines
        if (uname(&info) || sscanf(info.release, "%u.%u.", &major, &minor) != 2)
            ^~~~~~~~~~~~
./../kselftest.h:401:9: note: uninitialized use occurs here
        return major > min_major || (major == min_major && minor >= min_minor);
               ^~~~~
This is a bit of a red-herring as if the uname() call did fail, we would hit ksft_exit_fail_msg() which should exit.
Quoted 9 lines
Correct, although we have not really conveyed that to the compiler, right? exit() is noreturn, which means all functions that call exit() unconditionally are also noreturn, such as ksft_exit_fail_msg(). LLVM will figure this out once it performs inlining and such but that happens after clang's static analysis phase that this warning occurs in. I think a better solution would be to add __noreturn to the functions in tools/testing/selftests/kselftest.h that call exit(), so that the compiler is aware of this through all pipeline phases, maybe something like this? It resolves the wawrning for me.

Quoted 3 lines

No objection from me if this is the better approach.
Would you send that patch out?

Done: https://lore.kernel.org/20240411-mark-kselftest-exit-funcs-noreturn-v1-1-b027c948f586@kernel.org/

If you have to respin this series for some reason, feel free to include that change so that they go together, up to you though.

Cheers,
nathan

John Stultz

author maintainer

2024-04-10 23:26 UTC #5 lore raw

PATCH 3/3 selftests: timers: Fix abs() warning in posix_timers test

In reply to John Stultz

Building with clang, I'm seeing:
posix_timers.c:69:6: warning: absolute value function 'abs' given an argument of type 'long long' but has parameter of type 'int' which may cause truncation of value [-Wabsolute-value]

        if (abs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) {
            ^

So switch to using llabs() instead.

Cc Shuah Khan <[email protected]>

Cc Anna-Maria Behnsen <[email protected]>

Cc Frederic Weisbecker <[email protected]>

Cc Thomas Gleixner <[email protected]>

Cc Stephen Boyd <[email protected]>

Cc Nathan Chancellor <[email protected]>

Cc Nick Desaulniers <[email protected]>

Cc Bill Wendling <[email protected]>

Cc Justin Stitt <[email protected]>

Cc Oleg Nesterov <[email protected]>

Cc Andrew Morton <[email protected]>

Cc Edward Liaw <[email protected]>

Cc Carlos Llamas <[email protected]>

Cc [email protected]

Fixes 0bc4b0cf1570 ("selftests: add basic posix timers selftests")

Signed-off-by John Stultz <[email protected]>

---
 tools/testing/selftests/timers/posix_timers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

tools/testing/selftests/timers/posix_timers.c +1 -1

index 348f47176e0a..c001dd79179d 100644
@@ -66,7 +66,7 @@ static int check_diff(struct timeval start, struct timeval end)
 	diff = end.tv_usec - start.tv_usec;
 	diff += (end.tv_sec - start.tv_sec) * USECS_PER_SEC;
 
-	if (abs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) {
+	if (llabs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) {
 		printf("Diff too high: %lld..", diff);
 		return -1;
 	}

Signature · 1 line

2.44.0.478.gd926399ef9-goog

tip-bot2 for John Stultz

merge bot Applied

2024-04-12 12:15 UTC #6 lore raw

[tip: timers/urgent] selftests: timers: Fix abs() warning in posix_timers test

The following commit has been merged into the timers/urgent branch of tip:

Commit-ID:     ed366de8ec89d4f960d66c85fc37d9de22f7bf6d
Gitweb:        https://git.kernel.org/tip/ed366de8ec89d4f960d66c85fc37d9de22f7bf6d
Author:        John Stultz <[email protected]>
AuthorDate:    Wed, 10 Apr 2024 16:26:30 -07:00
Committer:     Thomas Gleixner <[email protected]>
CommitterDate: Fri, 12 Apr 2024 14:11:15 +02:00

selftests: timers: Fix abs() warning in posix_timers test

Building with clang results in the following warning:

posix_timers.c:69:6: warning: absolute value function 'abs' given an
argument of type 'long long' but has parameter of type 'int' which may cause truncation of value [-Wabsolute-value]
if (abs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) {
^
So switch to using llabs() instead.

Fixes 0bc4b0cf1570 ("selftests: add basic posix timers selftests")

Signed-off-by John Stultz <[email protected]>

Signed-off-by Thomas Gleixner <[email protected]>

Cc [email protected]

Link https://lore.kernel.org/r/[email protected] open here

---
 tools/testing/selftests/timers/posix_timers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

tools/testing/selftests/timers/posix_timers.c +1 -1

index 348f471..c001dd7 100644
@@ -66,7 +66,7 @@ static int check_diff(struct timeval start, struct timeval end)
 	diff = end.tv_usec - start.tv_usec;
 	diff += (end.tv_sec - start.tv_sec) * USECS_PER_SEC;
 
-	if (abs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) {
+	if (llabs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) {
 		printf("Diff too high: %lld..", diff);
 		return -1;
 	}

Justin Stitt

Acked-by on v1 1/3

2024-04-10 23:28 UTC #7 lore raw

In reply to John Stultz

Quoted 20 lines · John Stultz

After commit 6d029c25b71f ("selftests/timers/posix_timers:
Reimplement check_timer_distribution()") I started seeing the following warning building with an older gcc:
posix_timers.c:250:2: warning: format not a string literal and no format arguments [-Wformat-security]
  250 |  ksft_print_msg(errmsg);
      |  ^~~~~~~~~~~~~~
Fix this up by changing it to ksft_print_msg("%s", errmsg)
Cc Shuah Khan <[email protected]>
Cc Anna-Maria Behnsen <[email protected]>
Cc Frederic Weisbecker <[email protected]>
Cc Thomas Gleixner <[email protected]>
Cc Stephen Boyd <[email protected]>
Cc Nathan Chancellor <[email protected]>
Cc Nick Desaulniers <[email protected]>
Cc Bill Wendling <[email protected]>
Cc Justin Stitt <[email protected]>

Quoted 8 lines

Cc Oleg Nesterov <[email protected]>
Cc Andrew Morton <[email protected]>
Cc Edward Liaw <[email protected]>
Cc Carlos Llamas <[email protected]>
Cc [email protected]
Cc [email protected]
Fixes 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()")
Signed-off-by John Stultz <[email protected]>

Yep, makes sense.

Acked-by Justin Stitt <[email protected]>

Quoted 20 lines

---
 tools/testing/selftests/timers/posix_timers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

tools/testing/selftests/timers/posix_timers.c +1 -2

index d86a0e00711e..348f47176e0a 100644
@@ -247,7 +247,7 @@ static int check_timer_distribution(void)
                ksft_test_result_skip("check signal distribution (old kernel)\n");
        return 0;
 err:
-       ksft_print_msg(errmsg);
+       ksft_print_msg("%s", errmsg);
        return -1;
 }
 
--

2.44.0.478.gd926399ef9-goog

Oleg Nesterov

2024-04-11 09:40 UTC #8 lore raw

In reply to John Stultz

Quoted 8 lines · John Stultz

After commit 6d029c25b71f ("selftests/timers/posix_timers:
Reimplement check_timer_distribution()") I started seeing the following warning building with an older gcc:
posix_timers.c:250:2: warning: format not a string literal and no format arguments [-Wformat-security]
  250 |  ksft_print_msg(errmsg);
      |  ^~~~~~~~~~~~~~

...

tools/testing/selftests/timers/posix_timers.c static int check_timer_distribution(void) · line 251

Quoted 3 lines

tools/testing/selftests/timers/posix_timers.c +1 -1
-	ksft_print_msg(errmsg);
+	ksft_print_msg("%s", errmsg);
 	return -1;

Thanks,

Oleg.

Shuah Khan

maintainer

2024-04-11 20:45 UTC #9 lore raw

In reply to John Stultz

Quoted 1 line · John Stultz

After commit 6d029c25b71f ("selftests/timers/posix_timers:

Tried to apply this for linux-kselftest next with Nathan's patch. I can't find this commit in Linux 6.9-rc3? Is this is timers tree?

Quoted 35 lines

Reimplement check_timer_distribution()") I started seeing the following warning building with an older gcc:
posix_timers.c:250:2: warning: format not a string literal and no format arguments [-Wformat-security]
   250 |  ksft_print_msg(errmsg);
       |  ^~~~~~~~~~~~~~
Fix this up by changing it to ksft_print_msg("%s", errmsg)
Cc Shuah Khan <[email protected]>
Cc Anna-Maria Behnsen <[email protected]>
Cc Frederic Weisbecker <[email protected]>
Cc Thomas Gleixner <[email protected]>
Cc Stephen Boyd <[email protected]>
Cc Nathan Chancellor <[email protected]>
Cc Nick Desaulniers <[email protected]>
Cc Bill Wendling <[email protected]>
Cc Justin Stitt <[email protected]>
Cc Oleg Nesterov <[email protected]>
Cc Andrew Morton <[email protected]>
Cc Edward Liaw <[email protected]>
Cc Carlos Llamas <[email protected]>
Cc [email protected]
Cc [email protected]
Fixes 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()")
Signed-off-by John Stultz <[email protected]>
---
  tools/testing/selftests/timers/posix_timers.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
tools/testing/selftests/timers/posix_timers.c +0 -0
index d86a0e00711e..348f47176e0a 100644

tools/testing/selftests/timers/posix_timers.c static int check_timer_distribution(void) · line 253

Quoted 8 lines

tools/testing/selftests/timers/posix_timers.c +1 -1

@@ -247,7 +247,7 @@ static int check_timer_distribution(void)
  		ksft_test_result_skip("check signal distribution (old kernel)\n");
  	return 0;
  err:
-	ksft_print_msg(errmsg);
+	ksft_print_msg("%s", errmsg);
  	return -1;
  }

thanks,
-- Shuah

John Stultz

author maintainer

2024-04-11 20:53 UTC #10 lore raw

Quoted 7 lines · Shuah Khan

Quoted 1 line · John Stultz
After commit 6d029c25b71f ("selftests/timers/posix_timers:
Tried to apply this for linux-kselftest next with Nathan's patch. I can't find this commit in Linux 6.9-rc3? Is this is timers tree?

Yes, it in tip/timers/urgent.

thanks
-john

Shuah Khan

maintainer Acked-by

2024-04-11 21:12 UTC #11 lore raw

Quoted 11 lines · John Stultz

Quoted 7 lines · Shuah Khan
Quoted 1 line · John Stultz
After commit 6d029c25b71f ("selftests/timers/posix_timers:
Tried to apply this for linux-kselftest next with Nathan's patch. I can't find this commit in Linux 6.9-rc3? Is this is timers tree?
Yes, it in tip/timers/urgent.

Thank you. Assuming this is going through tip/timers/urgent

Acked-by Shuah Khan <[email protected]>

thanks,
-- Shuah

tip-bot2 for John Stultz

merge bot Applied

2024-04-12 12:15 UTC #12 lore raw

[tip: timers/urgent] selftests: timers: Fix posix_timers ksft_print_msg() warning

In reply to John Stultz

The following commit has been merged into the timers/urgent branch of tip:

Commit-ID:     e4a6bceac98eba3c00e874892736b34ea5fdaca3
Gitweb:        https://git.kernel.org/tip/e4a6bceac98eba3c00e874892736b34ea5fdaca3
Author:        John Stultz <[email protected]>
AuthorDate:    Wed, 10 Apr 2024 16:26:28 -07:00
Committer:     Thomas Gleixner <[email protected]>
CommitterDate: Fri, 12 Apr 2024 14:11:15 +02:00

selftests: timers: Fix posix_timers ksft_print_msg() warning

After commit 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()") the following warning occurs when building with an older gcc:

posix_timers.c:250:2: warning: format not a string literal and no format arguments [-Wformat-security]

  250 |  ksft_print_msg(errmsg);
      |  ^~~~~~~~~~~~~~

Fix this up by changing it to ksft_print_msg("%s", errmsg)

Fixes 6d029c25b71f ("selftests/timers/posix_timers: Reimplement check_timer_distribution()")

Signed-off-by John Stultz <[email protected]>

Signed-off-by Thomas Gleixner <[email protected]>

Acked-by Justin Stitt <[email protected]>

Acked-by Shuah Khan <[email protected]>

Cc [email protected]

Link https://lore.kernel.org/r/[email protected] open here

---
 tools/testing/selftests/timers/posix_timers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

tools/testing/selftests/timers/posix_timers.c +1 -1

index d86a0e0..348f471 100644
@@ -247,7 +247,7 @@ static int check_timer_distribution(void)
 		ksft_test_result_skip("check signal distribution (old kernel)\n");
 	return 0;
 err:
-	ksft_print_msg(errmsg);
+	ksft_print_msg("%s", errmsg);
 	return -1;
 }