Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Takashi Iwai <tiwai@suse.de>
To:     alsa-devel@alsa-project.org
Cc:     Hu Jiahui <kirin.say@gmail.com>, linux-kernel@vger.kernel.org
Subject: [PATCH 0/4] ALSA: pcm: Fix ioctl races
Date:   Tue, 22 Mar 2022 18:07:16 +0100
Message-Id: <20220322170720.3529-1-tiwai@suse.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Hi,

this is a patch set to address the recently reported bug for the racy
PCM ioctls.  In short, the current ALSA PCM core doesn't take enough
care of concurrent ioctl calls, and the concurrent calls may result in
a use-after-free.  The reported problem was the concurrent hw_free
calls, but there can be similar cases with other code paths like
hw_params, prepare, etc, too.

The patch set introduces the new runtime->buffer_mutex for protecting
those.  The first patch is the fix for the reported issue (the races
with hw_free), while the rest three are more hardening for the other
similar executions.

[ Note that the patch 3 was slightly modified from the version I sent
  to distros list, as I noticed possible lockdep (false-positive)
  warnings.  The behavior is almost same, just written differently. ]


thanks,

Takashi

===

Takashi Iwai (4):
  ALSA: pcm: Fix races among concurrent hw_params and hw_free calls
  ALSA: pcm: Fix races among concurrent read/write and buffer changes
  ALSA: pcm: Fix races among concurrent prepare and hw_params/hw_free
    calls
  ALSA: pcm: Fix races among concurrent prealloc proc writes

 include/sound/pcm.h     |  1 +
 sound/core/pcm.c        |  2 +
 sound/core/pcm_lib.c    |  4 ++
 sound/core/pcm_memory.c | 11 +++--
 sound/core/pcm_native.c | 93 +++++++++++++++++++++++++----------------
 5 files changed, 71 insertions(+), 40 deletions(-)

-- 
2.31.1