From 4ca5236c76357797e6d2feee9be46f4d8d93f46c Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 19 Feb 2018 17:16:01 +0100 Subject: [PATCH] ALSA: seq: Fix regression by incorrect ioctl_mutex usages This is the revised backport of the upstream commit b3defb791b26ea0683a93a4f49c77ec45ec96f10 We had another backport (e.g. 623e5c8ae32b in 4.4.115), but it applies the new mutex also to the code paths that are invoked via faked kernel-to-kernel ioctls. As reported recently, this leads to a deadlock at suspend (or other scenarios triggering the kernel sequencer client). This patch addresses the issue by taking the mutex only in the code paths invoked by user-space, just like the original fix patch does. Reported-and-tested-by: Andres Bertens Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- sound/core/seq/seq_clientmgr.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c index dd9da625b44e..f71c7d0b89cb 100644 --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -2189,7 +2189,6 @@ static int snd_seq_do_ioctl(struct snd_seq_client *client, unsigned int cmd, void __user *arg) { struct seq_ioctl_table *p; - int ret; switch (cmd) { case SNDRV_SEQ_IOCTL_PVERSION: @@ -2203,12 +2202,8 @@ static int snd_seq_do_ioctl(struct snd_seq_client *client, unsigned int cmd, if (! arg) return -EFAULT; for (p = ioctl_tables; p->cmd; p++) { - if (p->cmd == cmd) { - mutex_lock(&client->ioctl_mutex); - ret = p->func(client, arg); - mutex_unlock(&client->ioctl_mutex); - return ret; - } + if (p->cmd == cmd) + return p->func(client, arg); } snd_printd("seq unknown ioctl() 0x%x (type='%c', number=0x%02x)\n", cmd, _IOC_TYPE(cmd), _IOC_NR(cmd)); @@ -2219,11 +2214,15 @@ static int snd_seq_do_ioctl(struct snd_seq_client *client, unsigned int cmd, static long snd_seq_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct snd_seq_client *client = file->private_data; + long ret; if (snd_BUG_ON(!client)) return -ENXIO; - return snd_seq_do_ioctl(client, cmd, (void __user *) arg); + mutex_lock(&client->ioctl_mutex); + ret = snd_seq_do_ioctl(client, cmd, (void __user *) arg); + mutex_unlock(&client->ioctl_mutex); + return ret; } #ifdef CONFIG_COMPAT -- 2.39.2