forked from Minki/linux
d2c5cf88d5
This patch tries to address the still remaining issues in ALSA hrtimer driver: - Spurious use-after-free was detected in hrtimer callback - Incorrect rescheduling due to delayed start - WARN_ON() is triggered in hrtimer_forward() invoked in hrtimer callback The first issue happens only when the new timer is scheduled even while hrtimer is being closed. It's related with the second and third items; since ALSA timer core invokes hw.start callback during hrtimer interrupt, this may result in the explicit call of hrtimer_start(). Also, the similar problem is seen for the stop; ALSA timer core invokes hw.stop callback even in the hrtimer handler, too. Since we must not call the synced hrtimer_cancel() in such a context, it's just a hrtimer_try_to_cancel() call that doesn't properly work. Another culprit of the second and third items is the call of hrtimer_forward_now() before snd_timer_interrupt(). The timer->stick value may change during snd_timer_interrupt() call, but this possibility is ignored completely. For covering these subtle and messy issues, the following changes have been done in this patch: - A new flag, in_callback, is introduced in the private data to indicate that the hrtimer handler is being processed. - Both start and stop callbacks skip when called from (during) in_callback flag. - The hrtimer handler returns properly HRTIMER_RESTART and NORESTART depending on the running state now. - The hrtimer handler reprograms the expiry properly after snd_timer_interrupt() call, instead of before. - The close callback clears running flag and sets in_callback flag to block any further start/stop calls. Signed-off-by: Takashi Iwai <tiwai@suse.de> |
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| aoa | ||
| arm | ||
| atmel | ||
| core | ||
| drivers | ||
| firewire | ||
| hda | ||
| i2c | ||
| isa | ||
| mips | ||
| oss | ||
| parisc | ||
| pci | ||
| pcmcia | ||
| ppc | ||
| sh | ||
| soc | ||
| sparc | ||
| spi | ||
| synth | ||
| usb | ||
| ac97_bus.c | ||
| Kconfig | ||
| last.c | ||
| Makefile | ||
| sound_core.c | ||
| sound_firmware.c | ||