target: fix NULL pointer dereference bug alloc_page() fails to get memory
I am hitting this bug when the target is low in memory that fails the
alloc_page() for the newly submitted command. This is a sort of off-by-one
bug causing NULL pointer dereference in __free_page() since 'i' here is
really the counter of total pages that have been successfully allocated here.
Signed-off-by: Yi Zou <yi.zou@intel.com>
Cc: Andy Grover <agrover@redhat.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: Open-FCoE.org <devel@open-fcoe.org>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 0eaae23..a7589cc 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2294,9 +2294,9 @@
return 0;
out:
- while (i >= 0) {
- __free_page(sg_page(&cmd->t_data_sg[i]));
+ while (i > 0) {
i--;
+ __free_page(sg_page(&cmd->t_data_sg[i]));
}
kfree(cmd->t_data_sg);
cmd->t_data_sg = NULL;