linux-kernel - [PATCH 4.4 06/38] futex: Replace pointless printk in fixup

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Message-Id: <20210208145805.536973210@linuxfoundation.org>
Date:   Mon,  8 Feb 2021 16:00:28 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Lee Jones <lee.jones@...aro.org>
Subject: [PATCH 4.4 06/38] futex: Replace pointless printk in fixup_owner()

From: Lee Jones <lee.jones@...aro.org>

From: Thomas Gleixner <tglx@...utronix.de>

[ Upstream commit 04b79c55201f02ffd675e1231d731365e335c307 ]

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
Signed-off-by: Lee Jones <lee.jones@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 kernel/futex.c |   10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2412,14 +2412,10 @@ static int fixup_owner(u32 __user *uaddr
 
 	/*
 	 * 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);
 
 out:
 	return ret ? ret : locked;