linux/sound/core
Kelly Anderson 12ff414e2e ALSA: pcm: fix infinite loop in snd_pcm_update_hw_ptr0()
When period interrupts are disabled, snd_pcm_update_hw_ptr0() compares
the current time against the time estimated for the current hardware
pointer to detect xruns.  The somewhat fuzzy threshold in the while loop
makes it possible that hdelta becomes negative; the comparison being
done with unsigned types then makes the loop go through the entire 263
negative range, and, depending on the value, never reach an unsigned
value that is small enough to stop the loop.  Doing this with interrupts
disabled results in the machine locking up.

To prevent this, ensure that the loop condition uses signed types for
both operands so that the comparison is correctly done.

Many thanks to Kelly Anderson for debugging this.

Reported-by: Nix <nix@esperi.org.uk>
Reported-by: "Christopher K." <c.krooss@googlemail.com>
Reported-and-tested-by: Kelly Anderson <kelly@silka.with-linux.com>
Signed-off-by: Kelly Anderson <kelly@silka.with-linux.com>
[cl: remove unneeded casts; use a temp variable]
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Cc: 2.6.38 <stable@kernel.org>

Signed-off-by: Takashi Iwai <tiwai@suse.de>
2011-04-01 18:01:23 +02:00
..
oss ALSA: core: sparse cleanups 2011-02-14 17:10:11 +01:00
seq sound:core:seq:seq_ports.c Remove one to many n's in a word. 2011-02-27 10:05:53 +01:00
control_compat.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
control.c Merge branch 'topic/misc' into for-linus 2011-03-18 07:39:08 +01:00
device.c ALSA: core: sparse cleanups 2011-02-14 17:10:11 +01:00
hrtimer.c ALSA: hrtimer: remove superfluous tasklet invocation 2011-02-10 18:53:32 +01:00
hwdep_compat.c [PATCH] hwdep_compat missed __user annotations 2006-10-10 15:37:21 -07:00
hwdep.c ALSA: hwdep - Make open callback optional 2009-02-05 09:10:20 +01:00
info_oss.c ALSA: Kill snd_assert() in sound/core/* 2008-08-13 11:46:35 +02:00
info.c BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
init.c ALSA: Fix yet another race in disconnection 2011-03-25 19:22:50 +01:00
isadma.c ALSA: snd_dma_pointer workaround for chipsets with buggy DMA 2009-10-11 18:03:13 +02:00
jack.c ALSA: fix one memory leak in sound jack 2011-02-21 09:33:49 +01:00
Kconfig ALSA: sound/core/pcm_timer.c: use lib/gcd.c 2009-12-22 08:24:35 +01:00
Makefile ALSA: Fix SG-buffer DMA with non-coherent architectures 2009-07-08 14:20:20 +02:00
memalloc.c ALSA: core: sparse cleanups 2011-02-14 17:10:11 +01:00
memory.c [ALSA] Remove sound/driver.h 2008-01-31 17:29:48 +01:00
misc.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
pcm_compat.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
pcm_lib.c ALSA: pcm: fix infinite loop in snd_pcm_update_hw_ptr0() 2011-04-01 18:01:23 +02:00
pcm_memory.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
pcm_misc.c ALSA: core: sparse cleanups 2011-02-14 17:10:11 +01:00
pcm_native.c ALSA: vmalloc buffers should use normal mmap 2011-03-25 11:13:12 +01:00
pcm_timer.c ALSA: sound/core/pcm_timer.c: use lib/gcd.c 2009-12-22 08:24:35 +01:00
pcm.c ALSA: core: sparse cleanups 2011-02-14 17:10:11 +01:00
rawmidi_compat.c [ALSA] Remove xxx_t typedefs: Raw MIDI 2006-01-03 12:17:35 +01:00
rawmidi.c ALSA: rawmidi: fix oops (use after free) when unloading a driver module 2010-10-17 10:11:40 +02:00
rtctimer.c ALSA: hda - Convert from takslet_hi_schedule() to tasklet_schedule() 2008-12-18 12:17:55 +01:00
sgbuf.c ALSA: Fix vunmap and free order in snd_free_sgbuf_pages() 2009-03-18 08:04:01 +01:00
sound_oss.c ALSA: Remove warning message for invalid OSS minor ranges 2010-01-18 14:18:55 +01:00
sound.c Merge branch 'topic/workq-update' into topic/misc 2010-12-13 09:29:52 +01:00
timer_compat.c ALSA: Kill snd_assert() in sound/core/* 2008-08-13 11:46:35 +02:00
timer.c ALSA: sound/core: merge list_del()/list_add_tail() to list_move_tail() 2011-03-16 17:35:16 +01:00
vmaster.c ALSA: core: sparse cleanups 2011-02-14 17:10:11 +01:00