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From: Jens Axboe <>
To: Thomas Gleixner <>,
	syzbot <>,,,
Subject: Re: [syzbot] general protection fault in hrtimer_start_range_ns
Date: Wed, 8 Sep 2021 11:20:51 -0600	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 9/8/21 11:02 AM, Jens Axboe wrote:
> On 9/8/21 10:45 AM, Thomas Gleixner wrote:
>> On Mon, Sep 06 2021 at 03:28, syzbot wrote:
>>> syzbot found the following issue on:
>>> HEAD commit:    835d31d319d9 Merge tag 'media/v5.15-1' of git://git.kernel..
>>> git tree:       upstream
>>> console output:
>>> kernel config:
>>> dashboard link:
>>> compiler:       Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.1
>>> Unfortunately, I don't have any reproducer for this issue yet.
>>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>>> Reported-by:
>>> general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
>>> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
>>> CPU: 0 PID: 12936 Comm: iou-sqp-12929 Not tainted 5.14.0-syzkaller #0
>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
>>> RIP: 0010:lock_hrtimer_base kernel/time/hrtimer.c:173 [inline]
>> That's almost certainly deferencing hrtimer->base and as that is NULL
>> this looks like a not initialized hrtimer.
> Does certainly look like that, I'll take a look. And agree the next one
> looks like the same thing.

I think both are fallout from a regression that we had in linked
requests, where we'd queue requests that weren't fully prepared. Current
Linus -git should not have this problem:

These were the two related fixes:

      io_uring: fix queueing half-created requests
      io_uring: don't submit half-prepared drain request

Jens Axboe

  reply	other threads:[~2021-09-08 17:21 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-06 10:28 syzbot
2021-09-08 16:45 ` Thomas Gleixner
2021-09-08 17:02   ` Jens Axboe
2021-09-08 17:20     ` Jens Axboe [this message]
2021-09-08 21:11       ` Thomas Gleixner

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