On Tue, 24 May 2011, Jens Axboe wrote:
> On 2011-05-24 06:29, Parag Warudkar wrote:
> >
> > External DVD drive - connected when suspended, removed before resume.
> > Results in NULL pointer dereference in __blk_add_request on resume.
> >
> > *ffffffff811d6503: 48 89 58 08 mov %rbx,0x8(%rax) |
> > %ebx = ffff880131559020 <--- faulting instruction
> >
> > 48 89 58 08 appears only in list_add :
> >
> > static inline void list_add(struct list_head *new, struct list_head *head)
> > {
> > __list_add(new, head, head->next);
> > ffffffff81ac012c: 49 8b 04 24 mov (%r12),%rax
> > #ifndef CONFIG_DEBUG_LIST
> > static inline void __list_add(struct list_head *new,
> > struct list_head *prev,
> > struct list_head *next)
> > {
> > next->prev = new;
> > ffffffff81ac0130: 48 89 58 08 mov %rbx,0x8(%rax)
> >
> > AFAICS list_add is only called from one place in __elv_add_request :
> >
> > switch (where) {
> > case ELEVATOR_INSERT_REQUEUE:
> > case ELEVATOR_INSERT_FRONT:
> > rq->cmd_flags |= REQ_SOFTBARRIER;
> > ** list_add(&rq->queuelist, &q->queue_head);
> > break;
> >
> > Now, where is the patch? :)
>
> You forgot to attach it?
>
> This is clearly q == NULL [snip]
OK, I think this patch should do the trick.
Signed-off-by: Parag Warudkar <parag.lkml@xxxxxxxxx>
Reported-and-tested-by: Parag Warudkar <parag.lkml@xxxxxxxxx>
Check for device deletion before sending it a scsi command. This fixes an
OOPS I was seeing during resume when the external dvd drive was removed
while suspended.
diff --git a/drivers/scsi/scsi_ioctl.c b/drivers/scsi/scsi_ioctl.c
index d9564fb..cc4edbf 100644
--- a/drivers/scsi/scsi_ioctl.c
+++ b/drivers/scsi/scsi_ioctl.c
@@ -136,7 +136,7 @@ int scsi_set_medium_removal(struct scsi_device *sdev, char state)
char scsi_cmd[MAX_COMMAND_SIZE];
int ret;
- if (!sdev->removable || !sdev->lockable)
+ if (!sdev->removable || !sdev->lockable || sdev->sdev_state == SDEV_DEL)
return 0;
scsi_cmd[0] = ALLOW_MEDIUM_REMOVAL;
--
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