Thanks for report and the CC!
On Mon 19-12-22 10:52:57, Jens Axboe wrote:
> On 12/19/22 12:16 AM, Yi Zhang wrote:
> > Below issue was triggered during blktests nvme-tcp with for-next
> > (6.1.0, block, 2280cbf6), pls help check it
> >
> > [ 782.395936] run blktests nvme/013 at 2022-12-18 07:32:09
> > [ 782.425739] nvmet: adding nsid 1 to subsystem blktests-subsystem-1
> > [ 782.435780] nvmet_tcp: enabling port 0 (127.0.0.1:4420)
> > [ 782.446357] nvmet: creating nvm controller 1 for subsystem
> > blktests-subsystem-1 for NQN
> > nqn.2014-08.org.nvmexpress:uuid:4c4c4544-0042-3910-8039-c6c04f544833.
> > [ 782.460744] nvme nvme0: creating 32 I/O queues.
> > [ 782.466760] nvme nvme0: mapped 32/0/0 default/read/poll queues.
> > [ 782.479615] nvme nvme0: new ctrl: NQN "blktests-subsystem-1", addr
> > 127.0.0.1:4420
> > [ 783.612793] XFS (nvme0n1): Mounting V5 Filesystem
> > [ 783.650705] XFS (nvme0n1): Ending clean mount
> > [ 799.653271] ==================================================================
> > [ 799.660496] BUG: KFENCE: use-after-free read in bfq_exit_icq_bfqq+0x132/0x270
> > [ 799.669117] Use-after-free read at 0x000000008c692c21 (in kfence-#11):
> > [ 799.675647] bfq_exit_icq_bfqq+0x132/0x270
> > [ 799.679753] bfq_exit_icq+0x5b/0x80
> > [ 799.683255] exit_io_context+0x81/0xb0
> > [ 799.687015] do_exit+0x74b/0xaf0
> > [ 799.690256] kthread_exit+0x25/0x30
> > [ 799.693758] kthread+0xc8/0x110
> > [ 799.696904] ret_from_fork+0x1f/0x30
> > [ 799.701991] kfence-#11: 0x00000000f1839eaa-0x0000000011c747a1,
> > size=568, cache=bfq_queue
> > [ 799.711549] allocated by task 19533 on cpu 9 at 499.180335s:
> > [ 799.717218] bfq_get_queue+0xe0/0x530
> > [ 799.720884] bfq_get_bfqq_handle_split+0x75/0x120
> > [ 799.725592] bfq_insert_requests+0x1d15/0x2710
> > [ 799.730045] blk_mq_sched_insert_requests+0x5c/0x170
> > [ 799.735021] blk_mq_flush_plug_list+0x115/0x2e0
> > [ 799.739551] __blk_flush_plug+0xf2/0x130
> > [ 799.743479] blk_finish_plug+0x25/0x40
> > [ 799.747231] __iomap_dio_rw+0x520/0x7b0
> > [ 799.751070] btrfs_dio_write+0x42/0x50
> > [ 799.754832] btrfs_do_write_iter+0x2f4/0x5d0
> > [ 799.759112] nvmet_file_submit_bvec+0xa6/0xe0 [nvmet]
> > [ 799.764193] nvmet_file_execute_io+0x1a4/0x250 [nvmet]
> > [ 799.769349] process_one_work+0x1c4/0x380
> > [ 799.773361] worker_thread+0x4d/0x380
> > [ 799.777028] kthread+0xe6/0x110
> > [ 799.780174] ret_from_fork+0x1f/0x30
> > [ 799.785252] freed by task 19533 on cpu 9 at 799.653250s:
> > [ 799.790584] bfq_put_queue+0x183/0x2c0
> > [ 799.794344] bfq_exit_icq_bfqq+0x129/0x270
> > [ 799.798442] bfq_exit_icq+0x5b/0x80
> > [ 799.801934] exit_io_context+0x81/0xb0
> > [ 799.805687] do_exit+0x74b/0xaf0
> > [ 799.808920] kthread_exit+0x25/0x30
> > [ 799.812413] kthread+0xc8/0x110
> > [ 799.815561] ret_from_fork+0x1f/0x30
> > [ 799.820648] CPU: 9 PID: 19533 Comm: kworker/dying Not tainted 6.1.0 #1
> > [ 799.827181] Hardware name: Dell Inc. PowerEdge R640/0X45NX, BIOS
> > 2.15.1 06/15/2022
> > [ 799.834746] ==================================================================
> > [ 823.081364] XFS (nvme0n1): Unmounting Filesystem
> > [ 823.159994] nvme nvme0: Removing ctrl: NQN "blktests-subsystem-1"
Can you use addr2line to find which dereference is exactly causing the
problem? Hum, it seems to point to some strange issue because we've just
freed bfqq in this exit_io_context() invocation and seeing you are testing
linux-block tree I think the problem might be caused by 64dc8c732f5c
("block, bfq: fix possible uaf for 'bfqq->bic'"). Kuai, I think we've
messed up bfq_exit_icq_bfqq() and now bic_set_bfqq() can access already
freed 'old_bfqq'. So we need something like:
spin_lock_irqsave(&bfqd->lock, flags);
bfqq->bic = NULL;
- bfq_exit_bfqq(bfqd, bfqq);
bic_set_bfqq(bic, NULL, is_sync);
+ bfq_exit_bfqq(bfqd, bfqq);
spin_unlock_irqrestore(&bfqd->lock, flags);
so free bfqq only after it is removed from the bic...
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
