This is a note to let you know that I've just added the patch titled
ALSA: seq: Enable 'use' locking in all configurations
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
alsa-seq-enable-use-locking-in-all-configurations.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8009d506a1dd00cf436b0c4cca0dcec130580a21 Mon Sep 17 00:00:00 2001
From: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Date: Wed, 18 Oct 2017 00:45:49 +0100
Subject: ALSA: seq: Enable 'use' locking in all configurations
From: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
commit 8009d506a1dd00cf436b0c4cca0dcec130580a21 upstream.
The 'use' locking macros are no-ops if neither SMP or SND_DEBUG is
enabled. This might once have been OK in non-preemptible
configurations, but even in that case snd_seq_read() may sleep while
relying on a 'use' lock. So always use the proper implementations.
Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/core/seq/seq_lock.c | 4 ----
sound/core/seq/seq_lock.h | 12 ------------
2 files changed, 16 deletions(-)
--- a/sound/core/seq/seq_lock.c
+++ b/sound/core/seq/seq_lock.c
@@ -23,8 +23,6 @@
#include <sound/core.h>
#include "seq_lock.h"
-#if defined(CONFIG_SMP) || defined(CONFIG_SND_DEBUG)
-
/* wait until all locks are released */
void snd_use_lock_sync_helper(snd_use_lock_t *lockp, const char *file, int line)
{
@@ -42,5 +40,3 @@ void snd_use_lock_sync_helper(snd_use_lo
}
EXPORT_SYMBOL(snd_use_lock_sync_helper);
-
-#endif
--- a/sound/core/seq/seq_lock.h
+++ b/sound/core/seq/seq_lock.h
@@ -3,8 +3,6 @@
#include <linux/sched.h>
-#if defined(CONFIG_SMP) || defined(CONFIG_SND_DEBUG)
-
typedef atomic_t snd_use_lock_t;
/* initialize lock */
@@ -20,14 +18,4 @@ typedef atomic_t snd_use_lock_t;
void snd_use_lock_sync_helper(snd_use_lock_t *lock, const char *file, int line);
#define snd_use_lock_sync(lockp) snd_use_lock_sync_helper(lockp, __BASE_FILE__, __LINE__)
-#else /* SMP || CONFIG_SND_DEBUG */
-
-typedef spinlock_t snd_use_lock_t; /* dummy */
-#define snd_use_lock_init(lockp) /**/
-#define snd_use_lock_use(lockp) /**/
-#define snd_use_lock_free(lockp) /**/
-#define snd_use_lock_sync(lockp) /**/
-
-#endif /* SMP || CONFIG_SND_DEBUG */
-
#endif /* __SND_SEQ_LOCK_H */
Patches currently in stable-queue which might be from ben.hutchings@xxxxxxxxxxxxxxx are
queue-4.4/alsa-seq-enable-use-locking-in-all-configurations.patch