From: Jens Axboe <axboe@fb.com>
To: Ming Lei <tom.leiming@gmail.com>, <linux-kernel@vger.kernel.org>
Cc: <linux-block@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Dmitry Vyukov <dvyukov@google.com>, <stable@vger.kernel.org>
Subject: Re: [PATCH] block/loop: fix race between I/O and set_status
Date: Mon, 13 Feb 2017 09:37:34 -0700 [thread overview]
Message-ID: <a8f3d1d9-e299-3169-98b3-23334d881889@fb.com> (raw)
In-Reply-To: <1486784445-25300-1-git-send-email-tom.leiming@gmail.com>
On 02/10/2017 08:40 PM, Ming Lei wrote:
> Inside set_status, transfer need to setup again, so
> we have to drain IO before the transition, otherwise
> oops may be triggered like the following:
>
> divide error: 0000 [#1] SMP KASAN
> CPU: 0 PID: 2935 Comm: loop7 Not tainted 4.10.0-rc7+ #213
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
> 01/01/2011
> task: ffff88006ba1e840 task.stack: ffff880067338000
> RIP: 0010:transfer_xor+0x1d1/0x440 drivers/block/loop.c:110
> RSP: 0018:ffff88006733f108 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: ffff8800688d7000 RCX: 0000000000000059
> RDX: 0000000000000000 RSI: 1ffff1000d743f43 RDI: ffff880068891c08
> RBP: ffff88006733f160 R08: ffff8800688d7001 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800688d7000
> R13: ffff880067b7d000 R14: dffffc0000000000 R15: 0000000000000000
> FS: 0000000000000000(0000) GS:ffff88006d000000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000006c17e0 CR3: 0000000066e3b000 CR4: 00000000001406f0
> Call Trace:
> lo_do_transfer drivers/block/loop.c:251 [inline]
> lo_read_transfer drivers/block/loop.c:392 [inline]
> do_req_filebacked drivers/block/loop.c:541 [inline]
> loop_handle_cmd drivers/block/loop.c:1677 [inline]
> loop_queue_work+0xda0/0x49b0 drivers/block/loop.c:1689
> kthread_worker_fn+0x4c3/0xa30 kernel/kthread.c:630
> kthread+0x326/0x3f0 kernel/kthread.c:227
> ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430
> Code: 03 83 e2 07 41 29 df 42 0f b6 04 30 4d 8d 44 24 01 38 d0 7f 08
> 84 c0 0f 85 62 02 00 00 44 89 f8 41 0f b6 48 ff 25 ff 01 00 00 99 <f7>
> 7d c8 48 63 d2 48 03 55 d0 48 89 d0 48 89 d7 48 c1 e8 03 83
> RIP: transfer_xor+0x1d1/0x440 drivers/block/loop.c:110 RSP:
> ffff88006733f108
> ---[ end trace 0166f7bd3b0c0933 ]---
Thanks Ming, added for 4.11.
--
Jens Axboe
next prev parent reply other threads:[~2017-02-13 16:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-11 3:40 Ming Lei
2017-02-13 16:37 ` Jens Axboe [this message]
2017-03-13 21:14 ` Jiri Slaby
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