On 30/10/2018 17:49, Manjunath Patil wrote:
> info->nr_rings isn't adjusted in case of ENOMEM error from
> negotiate_mq(). This leads to kernel panic in error path.
>
> Typical call stack involving panic -
> #8 page_fault at ffffffff8175936f
> [exception RIP: blkif_free_ring+33]
> RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292
> ...
> #9 blkif_free at ffffffffa0149aaa [xen_blkfront]
> #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront]
> #11 blkback_changed at ffffffffa014ea8b [xen_blkfront]
> #12 xenbus_otherend_changed at ffffffff81424670
> #13 backend_changed at ffffffff81426dc3
> #14 xenwatch_thread at ffffffff81422f29
> #15 kthread at ffffffff810abe6a
> #16 ret_from_fork at ffffffff81754078
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 7ed8ce1c5fc7 ("xen-blkfront: move negotiate_mq to cover all cases of new VBDs")
> Signed-off-by: Manjunath Patil <manjunath.b.patil@xxxxxxxxxx>
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
Juergen
