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authorSwen Schillig <swen@vnet.ibm.com>2008-11-26 18:07:39 +0100
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-12-01 10:17:50 -0600
commit0ac55aa90f2c3bd08e57e52a513b82b18ce0a5bc (patch)
tree0899a1087c0c4cde4d44cdcd651a6a36e6dbee96
parent26871c97d52e50dc574bd01967926650643b142a (diff)
[SCSI] zfcp: eliminate race between validation and locking
The check of having a valid pointer was performed before the processing was secured by the lock. Between those two steps the pointer can turn invalid. During further processing another value is used (referenced by the pointer described above) as a function pointer which is never verified to be valid either, resulting under some circumstances in an invalid function call. This patch is fixing both issues. Signed-off-by: Swen Schillig <swen@vnet.ibm.com> Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
-rw-r--r--drivers/s390/scsi/zfcp_fsf.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index 0343d881bab..dc036769040 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -2116,18 +2116,21 @@ static inline void zfcp_fsf_trace_latency(struct zfcp_fsf_req *fsf_req)
static void zfcp_fsf_send_fcp_command_task_handler(struct zfcp_fsf_req *req)
{
- struct scsi_cmnd *scpnt = req->data;
+ struct scsi_cmnd *scpnt;
struct fcp_rsp_iu *fcp_rsp_iu = (struct fcp_rsp_iu *)
&(req->qtcb->bottom.io.fcp_rsp);
u32 sns_len;
char *fcp_rsp_info = (unsigned char *) &fcp_rsp_iu[1];
unsigned long flags;
- if (unlikely(!scpnt))
- return;
-
read_lock_irqsave(&req->adapter->abort_lock, flags);
+ scpnt = req->data;
+ if (unlikely(!scpnt)) {
+ read_unlock_irqrestore(&req->adapter->abort_lock, flags);
+ return;
+ }
+
if (unlikely(req->status & ZFCP_STATUS_FSFREQ_ABORTED)) {
set_host_byte(scpnt, DID_SOFT_ERROR);
set_driver_byte(scpnt, SUGGEST_RETRY);