Eric Lee / linux-smarc-t335x-v3.2

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Commit 63070a79ba482c274bad10ac8c4b587a3e011f2c

Authored by Thomas Gleixner
1 parent 5a7780e725
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

hrtimer: catch expired CLOCK_REALTIME timers early 

A CLOCK_REALTIME timer, which has an absolute expiry time less than
the clock realtime offset calls with a negative delta into the clock
events code and triggers the WARN_ON() there.

This is a false positive and needs to be prevented. Check the result
of timer->expires - timer->base->offset right away and return -ETIME
right away.

Thanks to Frans Pop, who reported the problem and tested the fixes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Frans Pop <elendil@planet.nl>

Showing 1 changed file with 11 additions and 0 deletions Side-by-side Diff

... ... @@ -442,6 +442,8 @@
442 442 ktime_t expires = ktime_sub(timer->expires, base->offset);
443 443 int res;
444 444  
  445 + WARN_ON_ONCE(timer->expires.tv64 < 0);
  446 +
445 447 /*
446 448 * When the callback is running, we do not reprogram the clock event
447 449 * device. The timer callback is either running on a different CPU or
... ... @@ -451,6 +453,15 @@
451 453 */
452 454 if (hrtimer_callback_running(timer))
453 455 return 0;
  456 +
  457 + /*
  458 + * CLOCK_REALTIME timer might be requested with an absolute
  459 + * expiry time which is less than base->offset. Nothing wrong
  460 + * about that, just avoid to call into the tick code, which
  461 + * has now objections against negative expiry values.
  462 + */
  463 + if (expires.tv64 < 0)
  464 + return -ETIME;
454 465  
455 466 if (expires.tv64 >= expires_next->tv64)
456 467 return 0;