From 0fcc4c8c044e117ac126ab6df4138ea9a67fa2a9 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 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 --- 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 cd97929fac66..dc28914fa72e 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -560,7 +560,7 @@ 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: