[PATCH] locking/ww_mutex: Initialize waiter.ww_ctx properly

[Sebastian Andrzej Siewior]

The gathering of the debug code for the ww-mutex initialized moved the
POISON initialiation into one spot and only set waiter.ww_ctx if the
ww_ctx was non-NULL thus keeping the POISON value in ww-mutex case.

For ww-mutex without a context it is expected to set the context to
NULL, the poison value was intended only for the regular mutex.

Move the waiter.ww_ctx where it was previously so it is initialized to
NULL if no ww_ctx was passed.

Fixes: c0afb0ffc06e6 ("locking/ww_mutex: Gather mutex_waiter initialization")
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
 kernel/locking/mutex.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 05b68931622d1..d1068b0b163af 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -614,8 +614,6 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 
 	debug_mutex_lock_common(lock, &waiter);
 	waiter.task = current;
-	if (ww_ctx)
-		waiter.ww_ctx = ww_ctx;
 
 	lock_contended(&lock->dep_map, ip);
 
@@ -630,6 +628,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 		ret = __ww_mutex_add_waiter(&waiter, lock, ww_ctx);
 		if (ret)
 			goto err_early_kill;
+		waiter.ww_ctx = ww_ctx;
 	}
 
 	set_current_state(state);
-- 
2.33.0