From: Amol Grover <frextrite@gmail.com>
Date: Sun, 16 Feb 2020 07:43:30 +0000 (+0530)
Subject: posix-timers: Pass lockdep expression to RCU lists
X-Git-Tag: v5.7-rc1~174^2~41
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5fb1c2a5bbf79ccca8d17cf97f66085be5808027;p=thirdparty%2Fkernel%2Flinux.git

posix-timers: Pass lockdep expression to RCU lists

head is traversed using hlist_for_each_entry_rcu outside an RCU read-side
critical section but under the protection of hash_lock.

Hence, add corresponding lockdep expression to silence false-positive
lockdep warnings, and harden RCU lists.

[ tglx: Removed the macro and put the condition right where it's used ]

Signed-off-by: Amol Grover <frextrite@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200216074330.GA14025@workstation-portable
---

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index ff0eb30de346d..07709ac30439a 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -121,7 +121,8 @@ static struct k_itimer *__posix_timers_find(struct hlist_head *head,
 {
 	struct k_itimer *timer;
 
-	hlist_for_each_entry_rcu(timer, head, t_hash) {
+	hlist_for_each_entry_rcu(timer, head, t_hash,
+				 lockdep_is_held(&hash_lock)) {
 		if ((timer->it_signal == sig) && (timer->it_id == id))
 			return timer;
 	}