Hi,
I'm sorry, but I tested this patch only now. And I just got another message from lockdep:
======================================================= [ INFO: possible circular locking dependency detected ] 2.6.24-rc7-dirty #79 ------------------------------------------------------- alsactl/953 is trying to acquire lock: (&codec->mutex){--..}, at: [<c01d03f0>] snd_soc_dapm_put_volsw+0xc4/0x218
but task is already holding lock: (&card->controls_rwsem){----}, at: [<c01bcfac>] snd_ctl_elem_write+0x24/0x13c
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&card->controls_rwsem){----}: [<c0058d84>] lock_acquire+0x6c/0x84 [<c0243eb4>] down_write+0x30/0x40 [<c01bd28c>] snd_ctl_add+0x54/0x1dc [<c01d2b78>] tosa_ac97_init+0x60/0xec [<c01ce5a0>] snd_soc_register_card+0x58/0x210 [<c01d193c>] wm9712_soc_probe+0x1f0/0x280 [<c01cf46c>] soc_probe+0x98/0x188 [<c015e998>] platform_drv_probe+0x20/0x24 [<c015d1dc>] driver_probe_device+0x100/0x1b8 [<c015d2a4>] __device_attach+0x10/0x14 [<c015c3a0>] bus_for_each_drv+0x48/0x84 [<c015d344>] device_attach+0x70/0x9c [<c015c308>] bus_attach_device+0x38/0x88 [<c015b068>] device_add+0x274/0x4bc [<c015ee40>] platform_device_add+0x100/0x158 [<c0016e04>] tosa_init+0x60/0x90 [<c00087e4>] kernel_init+0xc8/0x298 [<c0039cf0>] do_exit+0x0/0x760
-> #0 (&codec->mutex){--..}: [<c0058d84>] lock_acquire+0x6c/0x84 [<c0243b48>] mutex_lock_nested+0xf8/0x2bc [<c01d03f0>] snd_soc_dapm_put_volsw+0xc4/0x218 [<c01bd080>] snd_ctl_elem_write+0xf8/0x13c [<c01bde2c>] snd_ctl_ioctl+0x720/0xbfc [<c0099314>] do_ioctl+0x38/0x98 [<c0099620>] vfs_ioctl+0x2ac/0x2dc [<c0099690>] sys_ioctl+0x40/0x64 [<c001cf60>] ret_fast_syscall+0x0/0x2c
other info that might help us debug this:
2 locks held by alsactl/953: #0: (&card->power_lock){--..}, at: [<c01bde08>] snd_ctl_ioctl+0x6fc/0xbfc #1: (&card->controls_rwsem){----}, at: [<c01bcfac>] snd_ctl_elem_write+0x24/0x13c
stack backtrace: [<c00217d4>] (dump_stack+0x0/0x14) from [<c0056848>] (print_circular_bug_tail+0x78/0x94) [<c00567d0>] (print_circular_bug_tail+0x0/0x94) from [<c0058520>] (__lock_acquire+0x970/0xcf4) r6:c3f02538 r5:00000001 r4:c3f02560 [<c0057bb0>] (__lock_acquire+0x0/0xcf4) from [<c0058d84>] (lock_acquire+0x6c/0x84) [<c0058d18>] (lock_acquire+0x0/0x84) from [<c0243b48>] (mutex_lock_nested+0xf8/0x2bc) r7:c3f02220 r6:60000013 r5:c3d6eda8 r4:c3f9bd04 [<c0243a50>] (mutex_lock_nested+0x0/0x2bc) from [<c01d03f0>] (snd_soc_dapm_put_volsw+0xc4/0x218) [<c01d032c>] (snd_soc_dapm_put_volsw+0x0/0x218) from [<c01bd080>] (snd_ctl_elem_write+0xf8/0x13c) [<c01bcf88>] (snd_ctl_elem_write+0x0/0x13c) from [<c01bde2c>] (snd_ctl_ioctl+0x720/0xbfc) [<c01bd70c>] (snd_ctl_ioctl+0x0/0xbfc) from [<c0099314>] (do_ioctl+0x38/0x98) [<c00992dc>] (do_ioctl+0x0/0x98) from [<c0099620>] (vfs_ioctl+0x2ac/0x2dc) r6:bed526d8 r5:c3ed8288 r4:c3e93140 [<c0099374>] (vfs_ioctl+0x0/0x2dc) from [<c0099690>] (sys_ioctl+0x40/0x64) r9:c3f9a000 r8:c001d108 r6:c2c85513 r5:fffffff7 r4:c3e93140 [<c0099650>] (sys_ioctl+0x0/0x64) from [<c001cf60>] (ret_fast_syscall+0x0/0x2c) r6:00000002 r5:00000000 r4:00000000
2008/1/10, Mark Brown broonie@opensource.wolfsonmicro.com:
snd_soc_dapm_new_widgets() takes the codec lock when adding new widgets, causing lockdep warnings when applications later call down through ALSA to adjust controls. Since widgets are only added during probe this lock should be unneeded so don't take it.
Thanks to Dmitry Baryshkov dbaryshkov@gmail.com for reporting this issue.
Signed-off-by: Mark Brown broonie@opensource.wolfsonmicro.com Cc: Dmitry Baryshkov dbaryshkov@gmail.com
sound/soc/soc-dapm.c | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-)
diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c index a4ce882..f99cac1 100644 --- a/sound/soc/soc-dapm.c +++ b/sound/soc/soc-dapm.c @@ -972,7 +972,6 @@ int snd_soc_dapm_new_widgets(struct snd_soc_codec *codec) { struct snd_soc_dapm_widget *w;
mutex_lock(&codec->mutex); list_for_each_entry(w, &codec->dapm_widgets, list) { if (w->new)@@ -1007,7 +1006,6 @@ int snd_soc_dapm_new_widgets(struct snd_soc_codec *codec) }
dapm_power_widgets(codec, SND_SOC_DAPM_STREAM_NOP);
mutex_unlock(&codec->mutex); return 0;} EXPORT_SYMBOL_GPL(snd_soc_dapm_new_widgets); -- 1.5.3.8