Re: [PATCH v4.4.x] ALSA: seq: Fix regression by incorrect ioctl_mutex usages

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Feb 19, 2018 at 05:16:01PM +0100, Takashi Iwai wrote:
> 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 <abertensu@yahoo.com>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> ---
> 
> Tagged as 4.4.x, but should be applied to other older kernels, too.
> 
>  sound/core/seq/seq_clientmgr.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)

Thanks for this, now queued up.

greg k-h