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From: Ming Lei <>
To: Jens Axboe <>
Cc:, Bart Van Assche <>,
	Hannes Reinecke <>,
	John Garry <>,
	Christoph Hellwig <>,
	David Jeffery <>,
	Shinichiro Kawasaki <>
Subject: Re: [PATCH V7 0/4] blk-mq: fix request UAF related with iterating over tagset requests
Date: Fri, 14 May 2021 08:43:34 +0800	[thread overview]
Message-ID: <YJ3Htj8rlJ6uunqn@T590> (raw)
In-Reply-To: <>

On Tue, May 11, 2021 at 11:22:32PM +0800, Ming Lei wrote:
> Hi Jens,
> This patchset fixes the request UAF issue by one simple approach,
> without clearing ->rqs[] in fast path, please consider it for 5.13.
> 1) grab request's ref before calling ->fn in blk_mq_tagset_busy_iter,
> and release it after calling ->fn, so ->fn won't be called for one
> request if its queue is frozen, done in 2st patch
> 2) clearing any stale request referred in ->rqs[] before freeing the
> request pool, one per-tags spinlock is added for protecting
> grabbing request ref vs. clearing ->rqs[tag], so UAF by refcount_inc_not_zero
> in bt_tags_iter() is avoided, done in 3rd patch.
> V7:
> 	- fix one null-ptr-deref during updating nr_hw_queues, because
> 	blk_mq_clear_flush_rq_mapping() may touch non-mapped hw queue's
> 	tags, only patch 4/4 is modified, reported and verified by
> 	Shinichiro Kawasaki
> 	- run blktests and not see regression

Hi Jens,

We have been working on this issue for a bit long, so any chance to get
the fixes merged? Either 5.13 or 5.14 is fine.


  parent reply	other threads:[~2021-05-14  0:43 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-11 15:22 [PATCH V7 0/4] blk-mq: fix request UAF related with iterating over tagset requests Ming Lei
2021-05-11 15:22 ` [PATCH V7 1/4] block: avoid double io accounting for flush request Ming Lei
2021-05-11 15:22 ` [PATCH V7 2/4] blk-mq: grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter Ming Lei
2021-05-11 15:22 ` [PATCH V7 3/4] blk-mq: clear stale request in tags->rq[] before freeing one request pool Ming Lei
2021-05-11 15:22 ` [PATCH V7 4/4] blk-mq: clearing flush request reference in tags->rqs[] Ming Lei
2021-05-14  0:43 ` Ming Lei [this message]
2021-05-14 15:34   ` [PATCH V7 0/4] blk-mq: fix request UAF related with iterating over tagset requests Jens Axboe
2021-08-06  3:40 ` yukuai (C)
2021-08-06  4:12   ` Ming Lei
2021-08-06  7:50     ` yukuai (C)

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