kernel.git/sound/drivers/dummy.c, branch linux-5.0.y

sound: Use octal not symbolic permissions

2018-05-28T09:27:20Z

Convert the S_ symbolic permissions to their octal equivalents as using octal and not symbolic permissions is preferred by many as more readable. see: https://lkml.org/lkml/2016/8/2/1945 Done with automated conversion via: $ ./scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace Miscellanea: o Wrapped one multi-line call to a single line Signed-off-by: Joe Perches Acked-by: Vinod Koul Signed-off-by: Takashi Iwai

Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-01-30T00:50:58Z

Pull timer updates from Thomas Gleixner: "The timer departement presents: - A rather large rework of the hrtimer infrastructure which introduces softirq based hrtimers to replace the spread of hrtimer/tasklet combos which force the actual callback execution into softirq context. The approach is completely different from the initial implementation which you cursed at 10 years ago rightfully. The softirq based timers have their own queues and there is no nasty indirection and list reshuffling in the hard interrupt anymore. This comes with conversion of some of the hrtimer/tasklet users, the rest and the final removal of that horrible interface will come towards the end of the merge window or go through the relevant maintainer trees. Note: The top commit merged the last minute bugfix for the 10 years old CPU hotplug bug as I wanted to make sure that I fatfinger the merge conflict resolution myself. - The overhaul of the STM32 clocksource/clockevents driver - A new driver for the Spreadtrum SC9860 timer - A new driver dor the Actions Semi S700 timer - The usual set of fixes and updates all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits) usb/gadget/NCM: Replace tasklet with softirq hrtimer ALSA/dummy: Replace tasklet with softirq hrtimer hrtimer: Implement SOFT/HARD clock base selection hrtimer: Implement support for softirq based hrtimers hrtimer: Prepare handling of hard and softirq based hrtimers hrtimer: Add clock bases and hrtimer mode for softirq context hrtimer: Use irqsave/irqrestore around __run_hrtimer() hrtimer: Factor out __hrtimer_next_event_base() hrtimer: Factor out __hrtimer_start_range_ns() hrtimer: Remove the 'base' parameter from hrtimer_reprogram() hrtimer: Make remote enqueue decision less restrictive hrtimer: Unify remote enqueue handling hrtimer: Unify hrtimer removal handling hrtimer: Make hrtimer_force_reprogramm() unconditionally available hrtimer: Make hrtimer_reprogramm() unconditional hrtimer: Make hrtimer_cpu_base.next_timer handling unconditional hrtimer: Make the remote enqueue check unconditional hrtimer: Use accesor functions instead of direct access hrtimer: Make the hrtimer_cpu_base::hres_active field unconditional, to simplify the code hrtimer: Make room in 'struct hrtimer_cpu_base' ...

ALSA/dummy: Replace tasklet with softirq hrtimer

2018-01-16T08:51:22Z

The tasklet is used to defer the execution of snd_pcm_period_elapsed() to the softirq context. Using the HRTIMER_MODE_SOFT mode invokes the timer callback in softirq context as well which renders the tasklet useless. [o-takashi: avoid stall due to a call of hrtimer_cancel() on a callback of hrtimer] Signed-off-by: Thomas Gleixner Signed-off-by: Anna-Maria Gleixner Reviewed-by: Takashi Iwai Cc: Christoph Hellwig Cc: Jaroslav Kysela Cc: John Stultz Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Takashi Iwai Cc: Takashi Sakamoto Cc: alsa-devel@alsa-project.org Cc: keescook@chromium.org Link: http://lkml.kernel.org/r/20171221104205.7269-35-anna-maria@linutronix.de Signed-off-by: Ingo Molnar

ALSA: drivers: make array 'names' const, reduces object code size

2017-11-29T08:28:27Z

Don't populate array 'names' on the stack but instead make them static. Makes the object code smaller by 50 bytes: Before: text data bss dec hex filename 21237 9192 1120 31549 7b3d linux/sound/drivers/dummy.o After: text data bss dec hex filename 21095 9280 1120 31495 7b07 linux/sound/drivers/dummy.o (gcc version 7.2.0 x86_64) Signed-off-by: Colin Ian King Reviewed-by: Takashi Sakamoto Signed-off-by: Takashi Iwai

ALSA: drivers: Convert timers to use timer_setup()

2017-10-24T19:01:16Z

In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Signed-off-by: Kees Cook Signed-off-by: Takashi Iwai

ALSA: drivers: make snd_pcm_hardware const

2017-08-17T10:44:09Z

Make these const as they are only used in a copy operation. Done using Coccinelle. Signed-off-by: Bhumika Goyal Signed-off-by: Takashi Iwai

ALSA: dummy: Convert to new PCM copy ops

2017-06-02T17:37:56Z

It's a dummy ops, so just replacing it. Reviewed-by: Takashi Sakamoto Signed-off-by: Takashi Iwai

ALSA: dummy: Fix a use-after-free at closing

2016-06-24T13:18:32Z

syzkaller fuzzer spotted a potential use-after-free case in snd-dummy driver when hrtimer is used as backend: > ================================================================== > BUG: KASAN: use-after-free in rb_erase+0x1b17/0x2010 at addr ffff88005e5b6f68 > Read of size 8 by task syz-executor/8984 > ============================================================================= > BUG kmalloc-192 (Not tainted): kasan: bad access detected > ----------------------------------------------------------------------------- > > Disabling lock debugging due to kernel taint > INFO: Allocated in 0xbbbbbbbbbbbbbbbb age=18446705582212484632 > .... > [< none >] dummy_hrtimer_create+0x49/0x1a0 sound/drivers/dummy.c:464 > .... > INFO: Freed in 0xfffd8e09 age=18446705496313138713 cpu=2164287125 pid=-1 > [< none >] dummy_hrtimer_free+0x68/0x80 sound/drivers/dummy.c:481 > .... > Call Trace: > [] __asan_report_load8_noabort+0x3e/0x40 mm/kasan/report.c:333 > [< inline >] rb_set_parent include/linux/rbtree_augmented.h:111 > [< inline >] __rb_erase_augmented include/linux/rbtree_augmented.h:218 > [] rb_erase+0x1b17/0x2010 lib/rbtree.c:427 > [] timerqueue_del+0x78/0x170 lib/timerqueue.c:86 > [] __remove_hrtimer+0x90/0x220 kernel/time/hrtimer.c:903 > [< inline >] remove_hrtimer kernel/time/hrtimer.c:945 > [] hrtimer_try_to_cancel+0x22a/0x570 kernel/time/hrtimer.c:1046 > [] hrtimer_cancel+0x22/0x40 kernel/time/hrtimer.c:1066 > [] dummy_hrtimer_stop+0x91/0xb0 sound/drivers/dummy.c:417 > [] dummy_pcm_trigger+0x17f/0x1e0 sound/drivers/dummy.c:507 > [] snd_pcm_do_stop+0x160/0x1b0 sound/core/pcm_native.c:1106 > [] snd_pcm_action_single+0x76/0x120 sound/core/pcm_native.c:956 > [] snd_pcm_action+0x231/0x290 sound/core/pcm_native.c:974 > [< inline >] snd_pcm_stop sound/core/pcm_native.c:1139 > [] snd_pcm_drop+0x12d/0x1d0 sound/core/pcm_native.c:1784 > [] snd_pcm_common_ioctl1+0xfae/0x2150 sound/core/pcm_native.c:2805 > [] snd_pcm_capture_ioctl1+0x2a1/0x5e0 sound/core/pcm_native.c:2976 > [] snd_pcm_kernel_ioctl+0x11c/0x160 sound/core/pcm_native.c:3020 > [] snd_pcm_oss_sync+0x3a4/0xa30 sound/core/oss/pcm_oss.c:1693 > [] snd_pcm_oss_release+0x1ad/0x280 sound/core/oss/pcm_oss.c:2483 > ..... A workaround is to call hrtimer_cancel() in dummy_hrtimer_sync() which is called certainly before other blocking ops. Reported-by: Dmitry Vyukov Tested-by: Dmitry Vyukov Cc: Signed-off-by: Takashi Iwai

ALSA: dummy: Implement timer backend switching more safely

2016-02-08T07:15:35Z

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 Cc: Signed-off-by: Takashi Iwai

ALSA: dummy: Disable switching timer backend via sysfs

2016-01-28T07:13:54Z

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 Cc: Signed-off-by: Takashi Iwai