4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hannes Reinecke <hare@xxxxxxx>
commit eb72d0bb84eee5d0dc3044fd17b75e7101dabb57 upstream.
sd_check_events() is called asynchronously, and might race
with device removal. So always take a disk reference when
processing the event to avoid the device being removed while
the event is processed.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
Reviewed-by: Ewan D. Milne <emilne@xxxxxxxxxx>
Reviewed-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Jinpu Wang <jinpu.wang@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/sd.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1398,11 +1398,15 @@ static int media_not_present(struct scsi
**/
static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
{
- struct scsi_disk *sdkp = scsi_disk(disk);
- struct scsi_device *sdp = sdkp->device;
+ struct scsi_disk *sdkp = scsi_disk_get(disk);
+ struct scsi_device *sdp;
struct scsi_sense_hdr *sshdr = NULL;
int retval;
+ if (!sdkp)
+ return 0;
+
+ sdp = sdkp->device;
SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_check_events\n"));
/*
@@ -1459,6 +1463,7 @@ out:
kfree(sshdr);
retval = sdp->changed ? DISK_EVENT_MEDIA_CHANGE : 0;
sdp->changed = 0;
+ scsi_disk_put(sdkp);
return retval;
}