linux-kernel - [PATCH 05/13] rtmutex/rwlock: preserve state like a sleeping lock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <784bd79865718c40cd2564db00f430ae6ac014da.1554737688.git.tom.zanussi@linux.intel.com>
Date:   Mon,  8 Apr 2019 14:14:07 -0500
From:   Tom Zanussi <zanussi@...nel.org>
To:     linux-kernel@...r.kernel.org, linux-rt-users@...r.kernel.org
Cc:     rostedt@...dmis.org, tglx@...utronix.de, C.Emde@...dl.org,
        jkacur@...hat.com, bigeasy@...utronix.de,
        daniel.wagner@...mens.com, julia@...com, amartin@...dia.com
Subject: [PATCH 05/13] rtmutex/rwlock: preserve state like a sleeping lock

4.14.109-rt58-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>

[ Upstream commit 4a1bf9e54a013d55ab156cb462c68054cb52ee2d ]

The rwlock is spinning while acquiring a lock. Therefore it must become
a sleeping lock on RT and preserve its task state while sleeping and
waiting for the lock to become available.

Reported-by: Joe Korty <Joe.Korty@...current-rt.com>
Cc: stable-rt@...r.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Tom Zanussi <tom.zanussi@...ux.intel.com>
---
 kernel/locking/rwlock-rt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c
index f2e155b2c4a8..c3b91205161c 100644
--- a/kernel/locking/rwlock-rt.c
+++ b/kernel/locking/rwlock-rt.c
@@ -128,7 +128,7 @@ void __sched __read_rt_lock(struct rt_rw_lock *lock)
 	 * That would put Reader1 behind the writer waiting on
 	 * Reader2 to call read_unlock() which might be unbound.
 	 */
-	rt_mutex_init_waiter(&waiter, false);
+	rt_mutex_init_waiter(&waiter, true);
 	rt_spin_lock_slowlock_locked(m, &waiter, flags);
 	/*
 	 * The slowlock() above is guaranteed to return with the rtmutex is
-- 
2.14.1