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From: Jens Axboe <axboe@kernel.dk>
To: Junichi Nomura <j-nomura@ce.jp.nec.com>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"ming.lei@redhat.com" <ming.lei@redhat.com>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] block: check bi_size overflow before merge
Date: Tue, 12 Nov 2019 06:26:57 -0800	[thread overview]
Message-ID: <60f17a5b-aade-2a1f-8524-e8186a1dc66b@kernel.dk> (raw)
In-Reply-To: <20191112071957.GA10061@jeru.linux.bs1.fc.nec.co.jp>

On 11/11/19 11:19 PM, Junichi Nomura wrote:
> __bio_try_merge_page() may merge a page to bio without bio_full() check
> and cause bi_size overflow.
> 
> The overflow typically ends up with sd_init_command() warning on zero
> segment request with call trace like this:
> 
>      ------------[ cut here ]------------
>      WARNING: CPU: 2 PID: 1986 at drivers/scsi/scsi_lib.c:1025 scsi_init_io+0x156/0x180
>      CPU: 2 PID: 1986 Comm: kworker/2:1H Kdump: loaded Not tainted 5.4.0-rc7 #1
>      Workqueue: kblockd blk_mq_run_work_fn
>      RIP: 0010:scsi_init_io+0x156/0x180
>      RSP: 0018:ffffa11487663bf0 EFLAGS: 00010246
>      RAX: 00000000002be0a0 RBX: ffff8e6e9ff30118 RCX: 0000000000000000
>      RDX: 00000000ffffffe1 RSI: 0000000000000000 RDI: ffff8e6e9ff30118
>      RBP: ffffa11487663c18 R08: ffffa11487663d28 R09: ffff8e6e9ff30150
>      R10: 0000000000000001 R11: 0000000000000000 R12: ffff8e6e9ff30000
>      R13: 0000000000000001 R14: ffff8e74a1cf1800 R15: ffff8e6e9ff30000
>      FS:  0000000000000000(0000) GS:ffff8e6ea7680000(0000) knlGS:0000000000000000
>      CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>      CR2: 00007fff18cf0fe8 CR3: 0000000659f0a001 CR4: 00000000001606e0
>      Call Trace:
>       sd_init_command+0x326/0xb40 [sd_mod]
>       scsi_queue_rq+0x502/0xaa0
>       ? blk_mq_get_driver_tag+0xe7/0x120
>       blk_mq_dispatch_rq_list+0x256/0x5a0
>       ? elv_rb_del+0x24/0x30
>       ? deadline_remove_request+0x7b/0xc0
>       blk_mq_do_dispatch_sched+0xa3/0x140
>       blk_mq_sched_dispatch_requests+0xfb/0x170
>       __blk_mq_run_hw_queue+0x81/0x130
>       blk_mq_run_work_fn+0x1b/0x20
>       process_one_work+0x179/0x390
>       worker_thread+0x4f/0x3e0
>       kthread+0x105/0x140
>       ? max_active_store+0x80/0x80
>       ? kthread_bind+0x20/0x20
>       ret_from_fork+0x35/0x40
>      ---[ end trace f9036abf5af4a4d3 ]---
>      blk_update_request: I/O error, dev sdd, sector 2875552 op 0x1:(WRITE) flags 0x0 phys_seg 0 prio class 0
>      XFS (sdd1): writeback error on sector 2875552
> 
> __bio_try_merge_page() should check the overflow before actually doing
> merge.

Nice catch, applied for 5.4, thanks!

-- 
Jens Axboe


      parent reply	other threads:[~2019-11-12 14:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-12  7:19 [PATCH] block: check bi_size overflow before merge Junichi Nomura
2019-11-12  8:31 ` Christoph Hellwig
2019-11-12  8:46 ` Ming Lei
2019-11-12  9:03   ` Hannes Reinecke
2019-11-12  9:55     ` Ming Lei
2019-11-12 14:26 ` Jens Axboe [this message]

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