Messages in this thread | | | Subject | Re: [BUG] mm/vmalloc: ___might_sleep is called under a spinlock in __purge_vmap_area_lazy | From | Jia-Ju Bai <> | Date | Mon, 9 Oct 2017 12:48:22 +0800 |
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Thanks for your reply and explanation :) I will improve my analysis.
Thanks, Jia-Ju Bai
On 2017/10/9 12:10, Kirill A. Shutemov wrote: > On Mon, Oct 09, 2017 at 12:00:33PM +0800, Jia-Ju Bai wrote: >> The ___might_sleep is called under a spinlock, and the function call graph >> is: >> __purge_vmap_area_lazy (acquire the spinlock) >> cond_resched_lock >> ___might_sleep >> >> In this situation, ___might_sleep may prints error log message because a >> spinlock is held. >> A possible fix is to remove ___might_sleep in cond_resched_lock. >> >> This bug is found by my static analysis tool and my code review. > This analysis doesn't makes sense. > > The point of cond_resched_lock() is that it drops the lock, if resched is > required. > > ___might_sleep() is called with preempt_offset equal to > PREEMPT_LOCK_OFFSET, so it won't report error if it's the only lock we > hold. >
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