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Message-ID: <1552930085.152266.36.camel@acm.org>
Subject: Re: [PATCH 0/8]: blk-mq: use static_rqs to iterate busy tags
From:   Bart Van Assche <bvanassche@acm.org>
To:     Jianchao Wang <jianchao.w.wang@oracle.com>, axboe@kernel.dk
Cc:     hch@lst.de, jthumshirn@suse.de, hare@suse.de, josef@toxicpanda.com,
        sagi@grimberg.me, keith.busch@intel.com, jsmart2021@gmail.com,
        linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
        linux-kernel@vger.kernel.org
Date:   Mon, 18 Mar 2019 10:28:05 -0700
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References: <1552640264-26101-1-git-send-email-jianchao.w.wang@oracle.com>
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On Fri, 2019-03-15 at 16:57 +-0800, Jianchao Wang wrote:
+AD4 +AFs-2+AF0 https://marc.info/?l+AD0-linux-block+ACY-m+AD0-154526189023236+ACY-w+AD0-2

Hi Jianchao,

That is a reference to the +ACI-BUG: KASAN: use-after-free in bt+AF8-iter+ACI issue.
I think that issue can be fixed in another way than modifying all code that
iterates over tags, namely by adding an rcu+AF8-read+AF8-lock() / rcu+AF8-read+AF8-unlock()
pair in bt+AF8-for+AF8-each() and bt+AF8-tags+AF8-for+AF8-each() and by changing the calls in
blk+AF8-mq+AF8-free+AF8-rqs() and blk+AF8-free+AF8-flush+AF8-queue() that free the data structures
used by the tag iteration functions into kfree+AF8-rcu() or call+AF8-rcu() calls.

Thanks,

Bart.