From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: [PATCH RT 19/36] rtmutex: enable deadlock detection in ww_mutex_lock functions Date: Thu, 12 Mar 2015 15:21:58 -0400 Message-ID: <20150312192157.702218300@goodmis.org> References: <20150312192139.799127123@goodmis.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Paul Gortmaker , , Gustavo Bittencourt To: linux-kernel@vger.kernel.org, linux-rt-users Return-path: Content-Disposition: inline; filename=0019-rtmutex-enable-deadlock-detection-in-ww_mutex_lock-f.patch Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org 3.12.38-rt53-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Gustavo Bittencourt The functions ww_mutex_lock_interruptible and ww_mutex_lock should return -EDEADLK when faced with a deadlock. To do so, the paramenter detect_deadlock in rt_mutex_slowlock must be TRUE. This patch corrects potential deadlocks when running PREEMPT_RT with nouveau driver. Cc: stable-rt@vger.kernel.org Signed-off-by: Gustavo Bittencourt Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt --- kernel/rtmutex.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index 76cb88027fc2..e8a6555a670a 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -2166,7 +2166,8 @@ __ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ww_c might_sleep(); mutex_acquire_nest(&lock->base.dep_map, 0, 0, &ww_ctx->dep_map, _RET_IP_); - ret = rt_mutex_slowlock(&lock->base.lock, TASK_INTERRUPTIBLE, NULL, 0, ww_ctx); + ret = rt_mutex_slowlock(&lock->base.lock, TASK_INTERRUPTIBLE, NULL, + RT_MUTEX_FULL_CHAINWALK, ww_ctx); if (ret) mutex_release(&lock->base.dep_map, 1, _RET_IP_); else if (!ret && ww_ctx->acquired > 1) @@ -2184,7 +2185,8 @@ __ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx) might_sleep(); mutex_acquire_nest(&lock->base.dep_map, 0, 0, &ww_ctx->dep_map, _RET_IP_); - ret = rt_mutex_slowlock(&lock->base.lock, TASK_UNINTERRUPTIBLE, NULL, 0, ww_ctx); + ret = rt_mutex_slowlock(&lock->base.lock, TASK_UNINTERRUPTIBLE, NULL, + RT_MUTEX_FULL_CHAINWALK, ww_ctx); if (ret) mutex_release(&lock->base.dep_map, 1, _RET_IP_); else if (!ret && ww_ctx->acquired > 1) -- 2.1.4