Re: 4.12 NULL pointer dereference in kmem_cache_free on USB storage removal

[Bart Van Assche]

On Thu, 2017-07-13 at 23:24 +0300, Meelis Roos wrote:
> [258062.320700] RIP: 0010:kmem_cache_free+0x12/0x160
> [258062.320886] Call Trace:
> [258062.320897]  scsi_exit_rq+0x4d/0x60
> [258062.320909]  free_request_size+0x1c/0x30
> [258062.320923]  mempool_destroy+0x1d/0x60
> [258062.320935]  blk_exit_rl+0x1b/0x40
> [258062.320946]  __blk_release_queue+0x7d/0x120
> [258062.320959]  process_one_work+0x1af/0x340
> [258062.320972]  worker_thread+0x43/0x3e0
> [258062.320984]  kthread+0xfe/0x130
> [258062.320995]  ? create_worker+0x170/0x170
> [258062.321007]  ? kthread_create_on_node+0x40/0x40
> [258062.321022]  ret_from_fork+0x22/0x30

Hello Meelis,

Thank you for your report. Can you apply commit 8e6882545d8c ("scsi: Avoid
that scsi_exit_rq() triggers a use-after-free") on top of kernel v4.12 and
retest? That commit has been tagged "Cc: stable" so I hope that this patch
will be included in kernel v4.12.1. However, that kernel is not yet available
unfortunately ...

Thanks,

Bart.