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| author | Tejun Heo <tj@kernel.org> | 2010-11-01 11:39:19 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-12-09 13:24:17 -0800 |
| commit | 330b3db2ccf393581e2c06d2cb36e0689dd585e3 (patch) | |
| tree | 7dcbb5a4df689809dfd1e60181b9781ccaeedc2b | |
| parent | 99b6f6c69d47e4e61856884e96020bb4a57d6158 (diff) | |
| download | lwn-330b3db2ccf393581e2c06d2cb36e0689dd585e3.tar.gz lwn-330b3db2ccf393581e2c06d2cb36e0689dd585e3.zip | |
libata: fix NULL sdev dereference race in atapi_qc_complete()
commit 2a5f07b5ec098edc69e05fdd2f35d3fbb1235723 upstream.
SCSI commands may be issued between __scsi_add_device() and dev->sdev
assignment, so it's unsafe for ata_qc_complete() to dereference
dev->sdev->locked without checking whether it's NULL or not. Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/ata/libata-scsi.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index b9d3ba423cb2..feba4256aa59 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -2371,8 +2371,11 @@ static void atapi_qc_complete(struct ata_queued_cmd *qc) * * If door lock fails, always clear sdev->locked to * avoid this infinite loop. + * + * This may happen before SCSI scan is complete. Make + * sure qc->dev->sdev isn't NULL before dereferencing. */ - if (qc->cdb[0] == ALLOW_MEDIUM_REMOVAL) + if (qc->cdb[0] == ALLOW_MEDIUM_REMOVAL && qc->dev->sdev) qc->dev->sdev->locked = 0; qc->scsicmd->result = SAM_STAT_CHECK_CONDITION; |