On Thu, Aug 11, 2022 at 01:09:48AM +0900, Shigeru Yoshida wrote:
> hctx->user_data is set to vq in virtblk_init_hctx(). However, vq is
> freed on suspend and reallocated on resume. So, hctx->user_data is
> invalid after resume, and it will cause use-after-free accessing which
> will result in the kernel crash something like below:
>
> [ 22.428391] Call Trace:
> [ 22.428899] <TASK>
> [ 22.429339] virtqueue_add_split+0x3eb/0x620
> [ 22.430035] ? __blk_mq_alloc_requests+0x17f/0x2d0
> [ 22.430789] ? kvm_clock_get_cycles+0x14/0x30
> [ 22.431496] virtqueue_add_sgs+0xad/0xd0
> [ 22.432108] virtblk_add_req+0xe8/0x150
> [ 22.432692] virtio_queue_rqs+0xeb/0x210
> [ 22.433330] blk_mq_flush_plug_list+0x1b8/0x280
> [ 22.434059] __blk_flush_plug+0xe1/0x140
> [ 22.434853] blk_finish_plug+0x20/0x40
> [ 22.435512] read_pages+0x20a/0x2e0
> [ 22.436063] ? folio_add_lru+0x62/0xa0
> [ 22.436652] page_cache_ra_unbounded+0x112/0x160
> [ 22.437365] filemap_get_pages+0xe1/0x5b0
> [ 22.437964] ? context_to_sid+0x70/0x100
> [ 22.438580] ? sidtab_context_to_sid+0x32/0x400
> [ 22.439979] filemap_read+0xcd/0x3d0
> [ 22.440917] xfs_file_buffered_read+0x4a/0xc0
> [ 22.441984] xfs_file_read_iter+0x65/0xd0
> [ 22.442970] __kernel_read+0x160/0x2e0
> [ 22.443921] bprm_execve+0x21b/0x640
> [ 22.444809] do_execveat_common.isra.0+0x1a8/0x220
> [ 22.446008] __x64_sys_execve+0x2d/0x40
> [ 22.446920] do_syscall_64+0x37/0x90
> [ 22.447773] entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> This patch fixes this issue by getting vq from vblk, and removes
> virtblk_init_hctx().
>
> Fixes: 4e0400525691 ("virtio-blk: support polling I/O")
> Cc: "Suwan Kim" <suwan.kim027@xxxxxxxxx>
> Signed-off-by: Shigeru Yoshida <syoshida@xxxxxxxxxx>
> ---
> drivers/block/virtio_blk.c | 24 ++++++++++--------------
> 1 file changed, 10 insertions(+), 14 deletions(-)
Reviewed-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
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