From 94a6f1787e1f896585a093aa2f45cefbbef80f24 Mon Sep 17 00:00:00 2001 From: Yi Zou Date: Tue, 14 Aug 2012 16:06:43 -0700 Subject: [PATCH] target: fix NULL pointer dereference bug alloc_page() fails to get memory commit d0e27c88d795fb9647153063ec48051fd84e1731 upstream. 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 Cc: Andy Grover Cc: Nicholas Bellinger Cc: Open-FCoE.org Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman --- drivers/target/target_core_transport.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 0686d61adeae..222f1c5ff946 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -3675,9 +3675,9 @@ transport_generic_get_mem(struct se_cmd *cmd) 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; -- 2.39.5