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SubjectRe: [PATCH] mm/slub: fix a deadlock in shuffle_freelist()
On 2019-09-13 12:27:44 [-0400], Qian Cai wrote:

> Chain exists of:
> random_write_wait.lock --> &rq->lock --> batched_entropy_u32.lock
>
> Possible unsafe locking scenario:
>
> CPU0 CPU1
> ---- ----
> lock(batched_entropy_u32.lock);
> lock(&rq->lock);
> lock(batched_entropy_u32.lock);
> lock(random_write_wait.lock);

would this deadlock still occur if lockdep knew that
batched_entropy_u32.lock on CPU0 could be acquired at the same time
as CPU1 acquired its batched_entropy_u32.lock?

Sebastian

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