From: Amol Grover Date: Mon, 6 Apr 2020 10:59:50 +0000 (+0530) Subject: device_cgroup: Fix RCU list debugging warning X-Git-Tag: v5.4.69~67 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=8ebf2b77d7e5687d49fd9a1505d7fe30009a8433;p=users%2Fdwmw2%2Flinux.git device_cgroup: Fix RCU list debugging warning [ Upstream commit bc62d68e2a0a69fcdcf28aca8edb01abf306b698 ] exceptions may be traversed using list_for_each_entry_rcu() outside of an RCU read side critical section BUT under the protection of decgroup_mutex. Hence add the corresponding lockdep expression to fix the following false-positive warning: [ 2.304417] ============================= [ 2.304418] WARNING: suspicious RCU usage [ 2.304420] 5.5.4-stable #17 Tainted: G E [ 2.304422] ----------------------------- [ 2.304424] security/device_cgroup.c:355 RCU-list traversed in non-reader section!! Signed-off-by: Amol Grover Signed-off-by: James Morris Signed-off-by: Sasha Levin --- diff --git a/security/device_cgroup.c b/security/device_cgroup.c index 725674f3276d3..5d7bb91c64876 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -352,7 +352,8 @@ static bool match_exception_partial(struct list_head *exceptions, short type, { struct dev_exception_item *ex; - list_for_each_entry_rcu(ex, exceptions, list) { + list_for_each_entry_rcu(ex, exceptions, list, + lockdep_is_held(&devcgroup_mutex)) { if ((type & DEVCG_DEV_BLOCK) && !(ex->type & DEVCG_DEV_BLOCK)) continue; if ((type & DEVCG_DEV_CHAR) && !(ex->type & DEVCG_DEV_CHAR))