linux-kernel - [tip: locking/urgent] futex: Replace pointless printk in fixup

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Date:   Tue, 26 Jan 2021 20:04:59 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        stable@...r.kernel.org, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: locking/urgent] futex: Replace pointless printk in fixup_owner()

The following commit has been merged into the locking/urgent branch of tip:

Commit-ID:     04b79c55201f02ffd675e1231d731365e335c307
Gitweb:        https://git.kernel.org/tip/04b79c55201f02ffd675e1231d731365e335c307
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Tue, 19 Jan 2021 16:06:10 +01:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Tue, 26 Jan 2021 15:10:58 +01:00

futex: Replace pointless printk in fixup_owner()

If that unexpected case of inconsistent arguments ever happens then the
futex state is left completely inconsistent and the printk is not really
helpful. Replace it with a warning and make the state consistent.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: stable@...r.kernel.org
---
 kernel/futex.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index d5e61c2..5dc8f89 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2550,14 +2550,10 @@ static int fixup_owner(u32 __user *uaddr, struct futex_q *q, int locked)
 
 	/*
 	 * Paranoia check. If we did not take the lock, then we should not be
-	 * the owner of the rt_mutex.
+	 * the owner of the rt_mutex. Warn and establish consistent state.
 	 */
-	if (rt_mutex_owner(&q->pi_state->pi_mutex) == current) {
-		printk(KERN_ERR "fixup_owner: ret = %d pi-mutex: %p "
-				"pi-state %p\n", ret,
-				q->pi_state->pi_mutex.owner,
-				q->pi_state->owner);
-	}
+	if (WARN_ON_ONCE(rt_mutex_owner(&q->pi_state->pi_mutex) == current))
+		return fixup_pi_state_owner(uaddr, q, current);
 
 	return 0;
 }