Messages in this thread | | | From | Waiman Long <> | Subject | [PATCH 0/3] mm/kmemleak: Avoid soft lockup in kmemleak_scan() | Date | Sun, 12 Jun 2022 14:32:58 -0400 |
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There are 3 RCU-based object iteration loops in kmemleak_scan(). Because of the need to take RCU read lock, we can't insert cond_resched() into the loop like other parts of the function. As there can be millions of objects to be scanned, it takes a while to iterate all of them. The kmemleak functionality is usually enabled in a debug kernel which is much slower than a non-debug kernel. With sufficient number of kmemleak objects, the time to iterate them all may exceed 22s causing soft lockup.
watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [kmemleak:625]
This patch series make changes to the 3 object iteration loops in kmemleak_scan() to prevent them from causing soft lockup.
Waiman Long (3): mm/kmemleak: Use _irq lock/unlock variants in kmemleak_scan/_clear() mm/kmemleak: Skip unlikely objects in kmemleak_scan() without taking lock mm/kmemleak: Prevent soft lockup in first object iteration loop of kmemleak_scan()
mm/kmemleak.c | 52 ++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 41 insertions(+), 11 deletions(-)
-- 2.31.1
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