diff mbox series

[2/5] ALSA: pcm: Drop async signal support

Message ID 20220715102935.4695-3-tiwai@suse.de
State Superseded
Headers show
Series ALSA: Drop async signal support | expand

Commit Message

Takashi Iwai July 15, 2022, 10:29 a.m. UTC 
The async signal (SIGIO) support for ALSA PCM API has been never used
by real applications, but yet it can be a cause of various potential
deadlocks, as spotted by syzkaller.  Let's drop the feature as the
simplest solution.

Reported-by: syzbot+8285e973a41b5aa68902@syzkaller.appspotmail.com
Reported-by: syzbot+669c9abf11a6a011dd09@syzkaller.appspotmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 include/sound/pcm.h     |  1 -
 sound/core/pcm_lib.c    |  4 +---
 sound/core/pcm_native.c | 18 ------------------
 3 files changed, 1 insertion(+), 22 deletions(-)

Comments

kernel test robot July 16, 2022, 5:02 p.m. UTC | #1 
Hi Takashi,

I love your patch! Perhaps something to improve:

[auto build test WARNING on tiwai-sound/for-next]
[also build test WARNING on linus/master v5.19-rc6 next-20220715]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Takashi-Iwai/ALSA-Drop-async-signal-support/20220716-211853
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git for-next
config: i386-randconfig-a001 (https://download.01.org/0day-ci/archive/20220717/202207170009.xmmdeeBR-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
reproduce (this is a W=1 build):
        # https://github.com/intel-lab-lkp/linux/commit/6705167eb6bf093c8a099fa16c0aeb5f3da0dfba
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Takashi-Iwai/ALSA-Drop-async-signal-support/20220716-211853
        git checkout 6705167eb6bf093c8a099fa16c0aeb5f3da0dfba
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash sound/core/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   sound/core/pcm_lib.c: In function 'snd_pcm_period_elapsed_under_stream_lock':
>> sound/core/pcm_lib.c:1810:33: warning: variable 'runtime' set but not used [-Wunused-but-set-variable]
    1810 |         struct snd_pcm_runtime *runtime;
         |                                 ^~~~~~~


vim +/runtime +1810 sound/core/pcm_lib.c

e88e8ae639a490 Takashi Iwai     2006-04-28  1780  
^1da177e4c3f41 Linus Torvalds   2005-04-16  1781  /**
47271b1b98c980 Takashi Sakamoto 2021-06-10  1782   * snd_pcm_period_elapsed_under_stream_lock() - update the status of runtime for the next period
47271b1b98c980 Takashi Sakamoto 2021-06-10  1783   *						under acquired lock of PCM substream.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1784   * @substream: the instance of pcm substream.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1785   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1786   * This function is called when the batch of audio data frames as the same size as the period of
47271b1b98c980 Takashi Sakamoto 2021-06-10  1787   * buffer is already processed in audio data transmission.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1788   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1789   * The call of function updates the status of runtime with the latest position of audio data
47271b1b98c980 Takashi Sakamoto 2021-06-10  1790   * transmission, checks overrun and underrun over buffer, awaken user processes from waiting for
47271b1b98c980 Takashi Sakamoto 2021-06-10  1791   * available audio data frames, sampling audio timestamp, and performs stop or drain the PCM
47271b1b98c980 Takashi Sakamoto 2021-06-10  1792   * substream according to configured threshold.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1793   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1794   * The function is intended to use for the case that PCM driver operates audio data frames under
47271b1b98c980 Takashi Sakamoto 2021-06-10  1795   * acquired lock of PCM substream; e.g. in callback of any operation of &snd_pcm_ops in process
47271b1b98c980 Takashi Sakamoto 2021-06-10  1796   * context. In any interrupt context, it's preferrable to use ``snd_pcm_period_elapsed()`` instead
47271b1b98c980 Takashi Sakamoto 2021-06-10  1797   * since lock of PCM substream should be acquired in advance.
^1da177e4c3f41 Linus Torvalds   2005-04-16  1798   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1799   * Developer should pay enough attention that some callbacks in &snd_pcm_ops are done by the call of
47271b1b98c980 Takashi Sakamoto 2021-06-10  1800   * function:
^1da177e4c3f41 Linus Torvalds   2005-04-16  1801   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1802   * - .pointer - to retrieve current position of audio data transmission by frame count or XRUN state.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1803   * - .trigger - with SNDRV_PCM_TRIGGER_STOP at XRUN or DRAINING state.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1804   * - .get_time_info - to retrieve audio time stamp if needed.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1805   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1806   * Even if more than one periods have elapsed since the last call, you have to call this only once.
^1da177e4c3f41 Linus Torvalds   2005-04-16  1807   */
47271b1b98c980 Takashi Sakamoto 2021-06-10  1808  void snd_pcm_period_elapsed_under_stream_lock(struct snd_pcm_substream *substream)
^1da177e4c3f41 Linus Torvalds   2005-04-16  1809  {
877211f5e1b119 Takashi Iwai     2005-11-17 @1810  	struct snd_pcm_runtime *runtime;
^1da177e4c3f41 Linus Torvalds   2005-04-16  1811  
f5cdc9d4003a2f paulhsia         2019-11-13  1812  	if (PCM_RUNTIME_CHECK(substream))
47271b1b98c980 Takashi Sakamoto 2021-06-10  1813  		return;
f5cdc9d4003a2f paulhsia         2019-11-13  1814  	runtime = substream->runtime;
f5cdc9d4003a2f paulhsia         2019-11-13  1815  
^1da177e4c3f41 Linus Torvalds   2005-04-16  1816  	if (!snd_pcm_running(substream) ||
f240406babfe15 Jaroslav Kysela  2010-01-05  1817  	    snd_pcm_update_hw_ptr0(substream, 1) < 0)
6705167eb6bf09 Takashi Iwai     2022-07-15  1818  		return;
^1da177e4c3f41 Linus Torvalds   2005-04-16  1819
kernel test robot July 16, 2022, 5:53 p.m. UTC | #2 
Hi Takashi,

I love your patch! Perhaps something to improve:

[auto build test WARNING on tiwai-sound/for-next]
[also build test WARNING on linus/master v5.19-rc6 next-20220715]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Takashi-Iwai/ALSA-Drop-async-signal-support/20220716-211853
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git for-next
config: i386-randconfig-a011 (https://download.01.org/0day-ci/archive/20220717/202207170141.kyNwoI54-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 07022e6cf9b5b3baa642be53d0b3c3f1c403dbfd)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/6705167eb6bf093c8a099fa16c0aeb5f3da0dfba
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Takashi-Iwai/ALSA-Drop-async-signal-support/20220716-211853
        git checkout 6705167eb6bf093c8a099fa16c0aeb5f3da0dfba
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash sound/core/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> sound/core/pcm_lib.c:1810:26: warning: variable 'runtime' set but not used [-Wunused-but-set-variable]
           struct snd_pcm_runtime *runtime;
                                   ^
   1 warning generated.


vim +/runtime +1810 sound/core/pcm_lib.c

e88e8ae639a490 Takashi Iwai     2006-04-28  1780  
^1da177e4c3f41 Linus Torvalds   2005-04-16  1781  /**
47271b1b98c980 Takashi Sakamoto 2021-06-10  1782   * snd_pcm_period_elapsed_under_stream_lock() - update the status of runtime for the next period
47271b1b98c980 Takashi Sakamoto 2021-06-10  1783   *						under acquired lock of PCM substream.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1784   * @substream: the instance of pcm substream.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1785   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1786   * This function is called when the batch of audio data frames as the same size as the period of
47271b1b98c980 Takashi Sakamoto 2021-06-10  1787   * buffer is already processed in audio data transmission.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1788   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1789   * The call of function updates the status of runtime with the latest position of audio data
47271b1b98c980 Takashi Sakamoto 2021-06-10  1790   * transmission, checks overrun and underrun over buffer, awaken user processes from waiting for
47271b1b98c980 Takashi Sakamoto 2021-06-10  1791   * available audio data frames, sampling audio timestamp, and performs stop or drain the PCM
47271b1b98c980 Takashi Sakamoto 2021-06-10  1792   * substream according to configured threshold.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1793   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1794   * The function is intended to use for the case that PCM driver operates audio data frames under
47271b1b98c980 Takashi Sakamoto 2021-06-10  1795   * acquired lock of PCM substream; e.g. in callback of any operation of &snd_pcm_ops in process
47271b1b98c980 Takashi Sakamoto 2021-06-10  1796   * context. In any interrupt context, it's preferrable to use ``snd_pcm_period_elapsed()`` instead
47271b1b98c980 Takashi Sakamoto 2021-06-10  1797   * since lock of PCM substream should be acquired in advance.
^1da177e4c3f41 Linus Torvalds   2005-04-16  1798   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1799   * Developer should pay enough attention that some callbacks in &snd_pcm_ops are done by the call of
47271b1b98c980 Takashi Sakamoto 2021-06-10  1800   * function:
^1da177e4c3f41 Linus Torvalds   2005-04-16  1801   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1802   * - .pointer - to retrieve current position of audio data transmission by frame count or XRUN state.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1803   * - .trigger - with SNDRV_PCM_TRIGGER_STOP at XRUN or DRAINING state.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1804   * - .get_time_info - to retrieve audio time stamp if needed.
47271b1b98c980 Takashi Sakamoto 2021-06-10  1805   *
47271b1b98c980 Takashi Sakamoto 2021-06-10  1806   * Even if more than one periods have elapsed since the last call, you have to call this only once.
^1da177e4c3f41 Linus Torvalds   2005-04-16  1807   */
47271b1b98c980 Takashi Sakamoto 2021-06-10  1808  void snd_pcm_period_elapsed_under_stream_lock(struct snd_pcm_substream *substream)
^1da177e4c3f41 Linus Torvalds   2005-04-16  1809  {
877211f5e1b119 Takashi Iwai     2005-11-17 @1810  	struct snd_pcm_runtime *runtime;
^1da177e4c3f41 Linus Torvalds   2005-04-16  1811  
f5cdc9d4003a2f paulhsia         2019-11-13  1812  	if (PCM_RUNTIME_CHECK(substream))
47271b1b98c980 Takashi Sakamoto 2021-06-10  1813  		return;
f5cdc9d4003a2f paulhsia         2019-11-13  1814  	runtime = substream->runtime;
f5cdc9d4003a2f paulhsia         2019-11-13  1815  
^1da177e4c3f41 Linus Torvalds   2005-04-16  1816  	if (!snd_pcm_running(substream) ||
f240406babfe15 Jaroslav Kysela  2010-01-05  1817  	    snd_pcm_update_hw_ptr0(substream, 1) < 0)
6705167eb6bf09 Takashi Iwai     2022-07-15  1818  		return;
^1da177e4c3f41 Linus Torvalds   2005-04-16  1819
diff mbox series

Patch

diff --git a/include/sound/pcm.h b/include/sound/pcm.h
index 08cf4a5801f3..9bbd3742ef59 100644
--- a/include/sound/pcm.h
+++ b/include/sound/pcm.h
@@ -399,7 +399,6 @@  struct snd_pcm_runtime {
 	snd_pcm_uframes_t twake; 	/* do transfer (!poll) wakeup if non-zero */
 	wait_queue_head_t sleep;	/* poll sleep */
 	wait_queue_head_t tsleep;	/* transfer sleep */
-	struct fasync_struct *fasync;
 	bool stop_operating;		/* sync_stop will be called */
 	struct mutex buffer_mutex;	/* protect for buffer changes */
 	atomic_t buffer_accessing;	/* >0: in r/w operation, <0: blocked */
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 1fc7c50ffa62..a7b10ee5d57d 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -1815,14 +1815,12 @@  void snd_pcm_period_elapsed_under_stream_lock(struct snd_pcm_substream *substrea
 
 	if (!snd_pcm_running(substream) ||
 	    snd_pcm_update_hw_ptr0(substream, 1) < 0)
-		goto _end;
+		return;
 
 #ifdef CONFIG_SND_PCM_TIMER
 	if (substream->timer_running)
 		snd_timer_interrupt(substream->timer, 1);
 #endif
- _end:
-	kill_fasync(&runtime->fasync, SIGIO, POLL_IN);
 }
 EXPORT_SYMBOL(snd_pcm_period_elapsed_under_stream_lock);
 
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index aa0453e51595..c8e340b97277 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -3938,22 +3938,6 @@  static int snd_pcm_mmap(struct file *file, struct vm_area_struct *area)
 	return 0;
 }
 
-static int snd_pcm_fasync(int fd, struct file * file, int on)
-{
-	struct snd_pcm_file * pcm_file;
-	struct snd_pcm_substream *substream;
-	struct snd_pcm_runtime *runtime;
-
-	pcm_file = file->private_data;
-	substream = pcm_file->substream;
-	if (PCM_RUNTIME_CHECK(substream))
-		return -ENXIO;
-	runtime = substream->runtime;
-	if (runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
-		return -EBADFD;
-	return fasync_helper(fd, file, on, &runtime->fasync);
-}
-
 /*
  * ioctl32 compat
  */
@@ -4118,7 +4102,6 @@  const struct file_operations snd_pcm_f_ops[2] = {
 		.unlocked_ioctl =	snd_pcm_ioctl,
 		.compat_ioctl = 	snd_pcm_ioctl_compat,
 		.mmap =			snd_pcm_mmap,
-		.fasync =		snd_pcm_fasync,
 		.get_unmapped_area =	snd_pcm_get_unmapped_area,
 	},
 	{
@@ -4132,7 +4115,6 @@  const struct file_operations snd_pcm_f_ops[2] = {
 		.unlocked_ioctl =	snd_pcm_ioctl,
 		.compat_ioctl = 	snd_pcm_ioctl_compat,
 		.mmap =			snd_pcm_mmap,
-		.fasync =		snd_pcm_fasync,
 		.get_unmapped_area =	snd_pcm_get_unmapped_area,
 	}
 };