From: Bart Van Assche <bvanassche@acm.org>
To: Dongli Zhang <dongli.zhang@oracle.com>,
syzbot <syzbot+313d95e8a7a49263f88d@syzkaller.appspotmail.com>,
axboe@kernel.dk, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: KASAN: null-ptr-deref Write in blk_mq_map_swqueue
Date: Thu, 26 Mar 2020 19:52:06 -0700 [thread overview]
Message-ID: <523c2b61-476e-0fb6-12d9-37038d150fb7@acm.org> (raw)
In-Reply-To: <ffabca27-309e-4a6e-eac2-d03a56a7493a@oracle.com>
On 2020-03-26 17:19, Dongli Zhang wrote:
> I think the issue is because of line 2827, that is, the q->nr_hw_queues is
> updated too earlier. It is still possible the init would fail later.
>
> 2809 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
> 2810 struct request_queue *q)
> 2811 {
> 2812 int i, j, end;
> 2813 struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
> 2814
> 2815 if (q->nr_hw_queues < set->nr_hw_queues) {
> 2816 struct blk_mq_hw_ctx **new_hctxs;
> 2817
> 2818 new_hctxs = kcalloc_node(set->nr_hw_queues,
> 2819 sizeof(*new_hctxs), GFP_KERNEL,
> 2820 set->numa_node);
> 2821 if (!new_hctxs)
> 2822 return;
> 2823 if (hctxs)
> 2824 memcpy(new_hctxs, hctxs, q->nr_hw_queues *
> 2825 sizeof(*hctxs));
> 2826 q->queue_hw_ctx = new_hctxs;
> 2827 q->nr_hw_queues = set->nr_hw_queues;
> 2828 kfree(hctxs);
> 2829 hctxs = new_hctxs;
> 2830 }
Which kernel tree does this syzbot report refer to? Commit
d0930bb8f46b ("blk-mq: Fix a recently introduced regression in
blk_mq_realloc_hw_ctxs()") in Jens' tree removed line 2827 shown above.
Thanks,
Bart.
next prev parent reply other threads:[~2020-03-27 2:52 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-26 19:33 KASAN: null-ptr-deref Write in blk_mq_map_swqueue syzbot
2020-03-27 0:19 ` Dongli Zhang
2020-03-27 2:52 ` Bart Van Assche [this message]
2020-03-27 13:30 ` Dongli Zhang
2020-03-27 1:28 ` syzbot
2020-03-27 3:00 ` Bart Van Assche
2020-03-27 15:06 ` Jens Axboe
2020-06-25 3:01 ` syzbot
2020-06-25 4:05 ` Bart Van Assche
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