kernel.git/sound/drivers/dummy.c, branch linux-4.3.y

ALSA: dummy: Implement timer backend switching more safely

2016-02-19T22:28:32Z

commit ddce57a6f0a2d8d1bfacfa77f06043bc760403c2 upstream. Currently the selected timer backend is referred at any moment from the running PCM callbacks. When the backend is switched, it's possible to lead to inconsistency from the running backend. This was pointed by syzkaller fuzzer, and the commit [7ee96216c31a: ALSA: dummy: Disable switching timer backend via sysfs] disabled the dynamic switching for avoiding the crash. This patch improves the handling of timer backend switching. It keeps the reference to the selected backend during the whole operation of an opened stream so that it won't be changed by other streams. Together with this change, the hrtimer parameter is reenabled as writable now. NOTE: this patch also turned out to fix the still remaining race. Namely, ops was still replaced dynamically at dummy_pcm_open: static int dummy_pcm_open(struct snd_pcm_substream *substream) { .... dummy->timer_ops = &dummy_systimer_ops; if (hrtimer) dummy->timer_ops = &dummy_hrtimer_ops; Since dummy->timer_ops is common among all streams, and when the replacement happens during accesses of other streams, it may lead to a crash. This was actually triggered by syzkaller fuzzer and KASAN. This patch rewrites the code not to use the ops shared by all streams any longer, too. BugLink: http://lkml.kernel.org/r/CACT4Y+aZ+xisrpuM6cOXbL21DuM0yVxPYXf4cD4Md9uw0C3dBQ@mail.gmail.com Reported-by: Dmitry Vyukov Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: dummy: Disable switching timer backend via sysfs

2016-02-19T22:28:30Z

commit 7ee96216c31aabe1eb42fb91ff50dae9fcd014b2 upstream. ALSA dummy driver can switch the timer backend between system timer and hrtimer via its hrtimer module option. This can be also switched dynamically via sysfs, but it may lead to a memory corruption when switching is done while a PCM stream is running; the stream instance for the newly switched timer method tries to access the memory that was allocated by another timer method although the sizes differ. As the simplest fix, this patch just disables the switch via sysfs by dropping the writable bit. BugLink: http://lkml.kernel.org/r/CACT4Y+ZGEeEBntHW5WHn2GoeE0G_kRrCmUh6=dWyy-wfzvuJLg@mail.gmail.com Reported-by: Dmitry Vyukov Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: dummy: Replace CONFIG_PROC_FS with CONFIG_SND_PROC_FS

2015-05-29T05:47:50Z

Although there shouldn't be a problem in practice (the compiler should handle well), it's better to follow to the new Kconfig. Signed-off-by: Takashi Iwai

ALSA: dummy: make local data static

2015-05-26T10:59:26Z

Add missing prefix to make some local data static. Spotted by sparse: sound/drivers/dummy.c:159:20: warning: symbol 'model_emu10k1' was not declared. Should it be static? sound/drivers/dummy.c:165:20: warning: symbol 'model_rme9652' was not declared. Should it be static? .... Signed-off-by: Takashi Iwai

ALSA: dummy: use setup_timer and mod_timer

2015-01-19T09:49:52Z

Use setup_timer and mod_timer instead of structure assignments as it is the preferred way to setup and set the timer. Signed-off-by: Roman Kollar Signed-off-by: Jiri Slaby Signed-off-by: Takashi Iwai

ALSA: drivers: drop owner assignment from platform_drivers

2014-10-20T14:21:59Z

A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang

ALSA: drivers: Convert to snd_card_new() with a device pointer

2014-02-12T09:58:20Z

Also remove superfluous snd_card_set_dev() calls. Signed-off-by: Takashi Iwai

ALSA: replace strict_strto() with kstrto()

2013-07-21T09:56:18Z

The usage of strict_strto*() is not preferred, because strict_strto*() is obsolete. Thus, kstrto*() should be used. Signed-off-by: Jingoo Han Signed-off-by: Takashi Iwai

ALSA: Remove the rest of *_set_drvdata(NULL) calls

2013-05-29T10:50:59Z

A few calls are still left in parport drivers after this commit, which I'm not quite sure yet. Signed-off-by: Takashi Iwai

ALSA: drivers: remove __dev* attributes

2012-12-07T06:34:32Z

CONFIG_HOTPLUG is going away as an option. As result the __dev* markings will be going away. Remove use of __devinit, __devexit_p, __devinitdata, __devinitconst, and __devexit. Signed-off-by: Bill Pemberton Signed-off-by: Takashi Iwai