• Mark Fasheh's avatar
    [PATCH] Conditionally check expected_preempt_count in __resched_legal() · ba008404
    Mark Fasheh authored
    Commit 2d7d2535 ("fix cond_resched() fix")
    introduced an 'expected_preempt_count' parameter to __resched_legal() to
    fix a bug where it was returning a false negative when called from
    cond_resched_lock() and preemption was enabled.
    
    Unfortunately this broke things for when preemption is disabled.
    preempt_count() will always return zero, thus failing the check against any
    value of expected_preempt_count not equal to zero.  cond_resched_lock() for
    example, passes an expected_preempt_count value of 1.
    
    So fix the fix for the cond_resched() fix by skipping the check of
    preempt_count() against expected_preempt_count when preemption is disabled.
    
    Credit should go to Sunil Mushran for spotting the bug during testing.
    Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
    Acked-by: default avatarIngo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    ba008404
sched.c 177 KB