From 80ef021be19d3cdebe162c73b13d0f249d5bd2f3 Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Tue, 19 Mar 2019 02:36:59 +0100 Subject: [PATCH] device_cgroup: fix RCU imbalance in error case commit 0fcc4c8c044e117ac126ab6df4138ea9a67fa2a9 upstream. When dev_exception_add() returns an error (due to a failed memory allocation), make sure that we move the RCU preemption count back to where it was before we were called. We dropped the RCU read lock inside the loop body, so we can't just "break". sparse complains about this, too: $ make -s C=2 security/device_cgroup.o ./include/linux/rcupdate.h:647:9: warning: context imbalance in 'propagate_exception' - unexpected unlock Fixes: d591fb56618f ("device_cgroup: simplify cgroup tree walk in propagate_exception()") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn Acked-by: Michal Hocko Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- security/device_cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/device_cgroup.c b/security/device_cgroup.c index 5ef7e5240563..ea014df89428 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -569,7 +569,7 @@ static int propagate_exception(struct dev_cgroup *devcg_root, devcg->behavior == DEVCG_DEFAULT_ALLOW) { rc = dev_exception_add(devcg, ex); if (rc) - break; + return rc; } else { /* * in the other possible cases: