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Commit fcfdebe70759c74e2e701f69aaa7f0e5e32cf5a6

Authored by Takashi Iwai
1 parent 5f60e49608
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

ALSA: hrtimer - Fix lock-up 

The timer stop callback can be called from snd_timer_interrupt(), which
is called from the hrtimer callback.  Since hrtimer_cancel() waits for
the callback completion, this eventually results in a lock-up.

This patch fixes the problem by just toggling a flag at stop callback
and call hrtimer_cancel() later.

Reported-and-tested-by: Wojtek Zabolotny <W.Zabolotny@elka.pw.edu.pl>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Showing 1 changed file with 13 additions and 2 deletions Side-by-side Diff

sound/core/hrtimer.c
Diff comments   View file @ fcfdebe
... ... @@ -37,14 +37,22 @@
37 37 struct snd_hrtimer {
38 38 struct snd_timer *timer;
39 39 struct hrtimer hrt;
  40 + atomic_t running;
40 41 };
41 42  
42 43 static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
43 44 {
44 45 struct snd_hrtimer *stime = container_of(hrt, struct snd_hrtimer, hrt);
45 46 struct snd_timer *t = stime->timer;
  47 +
  48 + if (!atomic_read(&stime->running))
  49 + return HRTIMER_NORESTART;
  50 +
46 51 hrtimer_forward_now(hrt, ns_to_ktime(t->sticks * resolution));
47 52 snd_timer_interrupt(stime->timer, t->sticks);
  53 +
  54 + if (!atomic_read(&stime->running))
  55 + return HRTIMER_NORESTART;
48 56 return HRTIMER_RESTART;
49 57 }
50 58  
... ... @@ -58,6 +66,7 @@
58 66 hrtimer_init(&stime->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
59 67 stime->timer = t;
60 68 stime->hrt.function = snd_hrtimer_callback;
  69 + atomic_set(&stime->running, 0);
61 70 t->private_data = stime;
62 71 return 0;
63 72 }
64 73  
65 74  
... ... @@ -78,16 +87,18 @@
78 87 {
79 88 struct snd_hrtimer *stime = t->private_data;
80 89  
  90 + atomic_set(&stime->running, 0);
  91 + hrtimer_cancel(&stime->hrt);
81 92 hrtimer_start(&stime->hrt, ns_to_ktime(t->sticks * resolution),
82 93 HRTIMER_MODE_REL);
  94 + atomic_set(&stime->running, 1);
83 95 return 0;
84 96 }
85 97  
86 98 static int snd_hrtimer_stop(struct snd_timer *t)
87 99 {
88 100 struct snd_hrtimer *stime = t->private_data;
89   -
90   - hrtimer_cancel(&stime->hrt);
  101 + atomic_set(&stime->running, 0);
91 102 return 0;
92 103 }
93 104