[SCSI] megaraid_sas: fix memory leak if SGL has zero length entries

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@mork.no>
Cc: <stable@vger.kernel.org>
Acked-by: Adam Radford <aradford@gmail.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 6002d363c637..0177295599e0 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -4958,10 +4958,12 @@ 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);