3.12.38-rt53-rc1 stable review patch. If anyone has any objections, please let me know.
------------------ From: Mike Galbraith <[email protected]> Using mutex_acquire_nest() as used in __ww_mutex_lock() fixes the splat below. Remove superfluous line break in __ww_mutex_lock() as well. |============================================= |[ INFO: possible recursive locking detected ] |3.14.4-rt5 #26 Not tainted |--------------------------------------------- |Xorg/4298 is trying to acquire lock: | (reservation_ww_class_mutex){+.+.+.}, at: [<ffffffffa02b4270>] nouveau_gem_ioctl_pushbuf+0x870/0x19f0 [nouveau] |but task is already holding lock: | (reservation_ww_class_mutex){+.+.+.}, at: [<ffffffffa02b4270>] nouveau_gem_ioctl_pushbuf+0x870/0x19f0 [nouveau] |other info that might help us debug this: | Possible unsafe locking scenario: | CPU0 | ---- | lock(reservation_ww_class_mutex); | lock(reservation_ww_class_mutex); | | *** DEADLOCK *** | | May be due to missing lock nesting notation | |3 locks held by Xorg/4298: | #0: (&cli->mutex){+.+.+.}, at: [<ffffffffa02b597b>] nouveau_abi16_get+0x2b/0x100 [nouveau] | #1: (reservation_ww_class_acquire){+.+...}, at: [<ffffffffa0160cd2>] drm_ioctl+0x4d2/0x610 [drm] | #2: (reservation_ww_class_mutex){+.+.+.}, at: [<ffffffffa02b4270>] nouveau_gem_ioctl_pushbuf+0x870/0x19f0 [nouveau] Cc: [email protected] Signed-off-by: Mike Galbraith <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> --- kernel/rtmutex.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index 77f50d221d9c..76cb88027fc2 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -2165,7 +2165,7 @@ __ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ww_c might_sleep(); - mutex_acquire(&lock->base.dep_map, 0, 0, _RET_IP_); + 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); if (ret) mutex_release(&lock->base.dep_map, 1, _RET_IP_); @@ -2183,8 +2183,7 @@ __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_); + 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); if (ret) mutex_release(&lock->base.dep_map, 1, _RET_IP_); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
