From 59c7ecf1544e1841b5be8847e81bc9842f838e7e Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 15 Aug 2021 23:29:10 +0200
Subject: [PATCH] futex: Correct the number of requeued waiters for PI
Git-commit: 59c7ecf1544e1841b5be8847e81bc9842f838e7e
Patch-mainline: v5.15-rc1
References: bsc#1190137 bsc#1189998
The accounting is wrong when either the PI sanity check or the
requeue PI operation fails. Adjust it in the failure path.
Will be simplified in the next step.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211305.416427548@linutronix.de
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
kernel/futex.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/futex.c b/kernel/futex.c
index 8ddc87cae25c..543974285676 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2116,6 +2116,8 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
/* Ensure we requeue to the expected futex for requeue_pi. */
if (requeue_pi && !match_futex(this->requeue_pi_key, &key2)) {
+ /* Don't account for it */
+ task_count--;
ret = -EINVAL;
break;
}
@@ -2157,6 +2159,8 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
*/
this->pi_state = NULL;
put_pi_state(pi_state);
+ /* Don't account for it */
+ task_count--;
/*
* We stop queueing more waiters and let user
* space deal with the mess.
--
2.26.2