6.8-stable review patch. If anyone has any objections, please let me know.
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From: John Stultz jstultz@google.com
[ Upstream commit 076361362122a6d8a4c45f172ced5576b2d4a50d ]
The struct adjtimex freq field takes a signed value who's units are in shifted (<<16) parts-per-million.
Unfortunately for negative adjustments, the straightforward use of:
freq = ppm << 16 trips undefined behavior warnings with clang:
valid-adjtimex.c:66:6: warning: shifting a negative signed value is undefined [-Wshift-negative-value] -499<<16, ~~~~^ valid-adjtimex.c:67:6: warning: shifting a negative signed value is undefined [-Wshift-negative-value] -450<<16, ~~~~^ ..
Fix it by using a multiply by (1 << 16) instead of shifting negative values in the valid-adjtimex test case. Align the values for better readability.
Reported-by: Lee Jones joneslee@google.com Reported-by: Muhammad Usama Anjum usama.anjum@collabora.com Signed-off-by: John Stultz jstultz@google.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Muhammad Usama Anjum usama.anjum@collabora.com Link: https://lore.kernel.org/r/20240409202222.2830476-1-jstultz@google.com Link: https://lore.kernel.org/lkml/0c6d4f0d-2064-4444-986b-1d1ed782135f@collabora.... Signed-off-by: Sasha Levin sashal@kernel.org --- .../testing/selftests/timers/valid-adjtimex.c | 73 +++++++++---------- 1 file changed, 36 insertions(+), 37 deletions(-)
diff --git a/tools/testing/selftests/timers/valid-adjtimex.c b/tools/testing/selftests/timers/valid-adjtimex.c index 48b9a803235a8..d13ebde203221 100644 --- a/tools/testing/selftests/timers/valid-adjtimex.c +++ b/tools/testing/selftests/timers/valid-adjtimex.c @@ -21,9 +21,6 @@ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ - - - #include <stdio.h> #include <stdlib.h> #include <time.h> @@ -62,45 +59,47 @@ int clear_time_state(void) #define NUM_FREQ_OUTOFRANGE 4 #define NUM_FREQ_INVALID 2
+#define SHIFTED_PPM (1 << 16) + long valid_freq[NUM_FREQ_VALID] = { - -499<<16, - -450<<16, - -400<<16, - -350<<16, - -300<<16, - -250<<16, - -200<<16, - -150<<16, - -100<<16, - -75<<16, - -50<<16, - -25<<16, - -10<<16, - -5<<16, - -1<<16, + -499 * SHIFTED_PPM, + -450 * SHIFTED_PPM, + -400 * SHIFTED_PPM, + -350 * SHIFTED_PPM, + -300 * SHIFTED_PPM, + -250 * SHIFTED_PPM, + -200 * SHIFTED_PPM, + -150 * SHIFTED_PPM, + -100 * SHIFTED_PPM, + -75 * SHIFTED_PPM, + -50 * SHIFTED_PPM, + -25 * SHIFTED_PPM, + -10 * SHIFTED_PPM, + -5 * SHIFTED_PPM, + -1 * SHIFTED_PPM, -1000, - 1<<16, - 5<<16, - 10<<16, - 25<<16, - 50<<16, - 75<<16, - 100<<16, - 150<<16, - 200<<16, - 250<<16, - 300<<16, - 350<<16, - 400<<16, - 450<<16, - 499<<16, + 1 * SHIFTED_PPM, + 5 * SHIFTED_PPM, + 10 * SHIFTED_PPM, + 25 * SHIFTED_PPM, + 50 * SHIFTED_PPM, + 75 * SHIFTED_PPM, + 100 * SHIFTED_PPM, + 150 * SHIFTED_PPM, + 200 * SHIFTED_PPM, + 250 * SHIFTED_PPM, + 300 * SHIFTED_PPM, + 350 * SHIFTED_PPM, + 400 * SHIFTED_PPM, + 450 * SHIFTED_PPM, + 499 * SHIFTED_PPM, };
long outofrange_freq[NUM_FREQ_OUTOFRANGE] = { - -1000<<16, - -550<<16, - 550<<16, - 1000<<16, + -1000 * SHIFTED_PPM, + -550 * SHIFTED_PPM, + 550 * SHIFTED_PPM, + 1000 * SHIFTED_PPM, };
#define LONG_MAX (~0UL>>1)