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authorXiaotian Feng <xtfeng@gmail.com>2012-12-13 16:12:18 +0800
committerJeff Garzik <jgarzik@redhat.com>2012-12-14 09:40:34 -0500
commit26cd4d65deba587f3cf2329b6869ce02bcbe68ec (patch)
treee62b5a258bca2f0fe17b79771a75f053d1a90119
parent39f80acb9fe5adff216bde33c554e4bf5f6eec12 (diff)
[libata] fix Null pointer dereference on disk error
Following oops were observed when disk error happened: [ 4272.896937] sd 0:0:0:0: [sda] Unhandled error code [ 4272.896939] sd 0:0:0:0: [sda] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK [ 4272.896942] sd 0:0:0:0: [sda] CDB: Read(10): 28 00 00 5a de a7 00 00 08 00 [ 4272.896951] end_request: I/O error, dev sda, sector 5955239 [ 4291.574947] BUG: unable to handle kernel NULL pointer dereference at (null) [ 4291.658305] IP: [] ahci_activity_show+0x1/0x40 [ 4291.730090] PGD 76dbbc067 PUD 6c4fba067 PMD 0 [ 4291.783408] Oops: 0000 [#1] SMP [ 4291.822100] last sysfs file: /sys/devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/sw_activity [ 4291.934235] CPU 9 [ 4291.958301] Pid: 27942, comm: hwinfo ...... ata_scsi_find_dev could return NULL, so ata_scsi_activity_{show,store} should check if atadev is NULL. Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com> Cc: James Bottomley <JBottomley@Parallels.com> Cc: stable@kernel.org Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
-rw-r--r--drivers/ata/libata-scsi.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index a6df6a351d6..7c337e754da 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -309,7 +309,8 @@ ata_scsi_activity_show(struct device *dev, struct device_attribute *attr,
struct ata_port *ap = ata_shost_to_port(sdev->host);
struct ata_device *atadev = ata_scsi_find_dev(ap, sdev);
- if (ap->ops->sw_activity_show && (ap->flags & ATA_FLAG_SW_ACTIVITY))
+ if (atadev && ap->ops->sw_activity_show &&
+ (ap->flags & ATA_FLAG_SW_ACTIVITY))
return ap->ops->sw_activity_show(atadev, buf);
return -EINVAL;
}
@@ -324,7 +325,8 @@ ata_scsi_activity_store(struct device *dev, struct device_attribute *attr,
enum sw_activity val;
int rc;
- if (ap->ops->sw_activity_store && (ap->flags & ATA_FLAG_SW_ACTIVITY)) {
+ if (atadev && ap->ops->sw_activity_store &&
+ (ap->flags & ATA_FLAG_SW_ACTIVITY)) {
val = simple_strtoul(buf, NULL, 0);
switch (val) {
case OFF: case BLINK_ON: case BLINK_OFF: