[PATCH 010/106] [SCSI] megaraid_sas: fix memory leak if SGL has zero length entries

[Luis Henriques]

3.5.7.18 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= <bjorn at mork.no>

commit 7a6a731bd00ca90d0e250867c3b9c05b5ff0fa49 upstream.

commit 98cb7e44 ([SCSI] megaraid_sas: Sanity check user
supplied length before passing it to dma_alloc_coherent())
introduced a memory leak.  Memory allocated for entries
following zero length SGL entries will not be freed.

Reference: http://bugs.debian.org/688198

Signed-off-by: Bjørn Mork <bjorn at mork.no>
Acked-by: Adam Radford <aradford at gmail.com>
Signed-off-by: James Bottomley <JBottomley at Parallels.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/scsi/megaraid/megaraid_sas_base.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index ed38454..d525297 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -4817,10 +4817,12 @@ megasas_mgmt_fw_ioctl(struct megasas_instance *instance,
 				    sense, sense_handle);
 	}
 
-	for (i = 0; i < ioc->sge_count && kbuff_arr[i]; i++) {
-		dma_free_coherent(&instance->pdev->dev,
-				    kern_sge32[i].length,
-				    kbuff_arr[i], kern_sge32[i].phys_addr);
+	for (i = 0; i < ioc->sge_count; i++) {
+		if (kbuff_arr[i])
+			dma_free_coherent(&instance->pdev->dev,
+					  kern_sge32[i].length,
+					  kbuff_arr[i],
+					  kern_sge32[i].phys_addr);
 	}
 
 	megasas_return_cmd(instance, cmd);
-- 
1.8.3.2