At Wed, 1 Sep 2010 04:19:24 -0400, Chuck Ebbert wrote:

https://bugzilla.redhat.com/show_bug.cgi?id=628404

general protection fault: 0000 [#1] SMP last sysfs file: /sys/devices/pci0000:00/0000:00:1b.0/sound/card0/pcmC0D0c/pcm_class CPU 1 Modules linked in: vfat fat fuse ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat bridge stp llc sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf ip6t_REJECT nf_conntrack_ipv6 xt_physdev ip6table_filter ip6_tables kvm_intel kvm uinput snd_hda_codec_conexant usblp arc4 ecb snd_hda_intel snd_hda_codec snd_hwdep snd_seq snd_seq_device iwlagn snd_pcm iwlcore thinkpad_acpi snd_timer snd i2c_i801 mac80211 soundcore microcode iTCO_wdt iTCO_vendor_support e1000e cfg80211 wmi snd_page_alloc rfkill ipv6 usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]

Pid: 16071, comm: pulseaudio Not tainted 2.6.36-0.11.rc2.git5.fc15.x86_64 #1 74585FU/74585FU RIP: 0010:[<ffffffffa0296742>] [<ffffffffa0296742>] snd_pcm_substream_proc_status_read+0x164/0x1ad [snd_pcm] RSP: 0018:ffff8801178c1b58 EFLAGS: 00010292 RAX: 6b6b6b6b6b6b6b6b RBX: ffff88003d993bc8 RCX: 0000000000000000 RDX: ffffffffa02a1996 RSI: ffffffffa02a1997 RDI: ffff88003d993bc8 RBP: ffff8801178c1c18 R08: 0000000000000006 R09: 00000000fffffff7 R10: ffff8800044ea048 R11: 0000000000000000 R12: ffff8801332d31b0 R13: ffff88013438d488 R14: ffff88013438e050 R15: ffff880111131880 FS: 00007fbccba77780(0000) GS:ffff880002e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007fbf324db008 CR3: 00000001157be000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process pulseaudio (pid: 16071, threadinfo ffff8801178c0000, task ffff880130f88000) Stack: 0000000000000003 0000000000005e84 000000002ee6c142 0000000000005e85 <0> 000000001624774a 0000000000000000 00000000000064b0 00000000000064b0 <0> 00000000000064b0 00000000000064b0 0000000000000000 0000000000000000 Call Trace: [<ffffffffa020ac22>] snd_info_entry_open+0x307/0x389 [snd] [<ffffffff81179034>] proc_reg_open+0xfa/0x17a [<ffffffffa020a91b>] ? snd_info_entry_open+0x0/0x389 [snd] [<ffffffffa0209fa7>] ? snd_info_entry_release+0x0/0xd8 [snd] [<ffffffff81178f3a>] ? proc_reg_open+0x0/0x17a [<ffffffff81128f1f>] __dentry_open+0x1c2/0x338 [<ffffffff81129da0>] nameidata_to_filp+0x3f/0x50 [<ffffffff81136200>] do_last+0x432/0x5af [<ffffffff81246a75>] ? __raw_spin_lock_init+0x31/0x50 [<ffffffff811365ad>] do_filp_open+0x230/0x5e1 [<ffffffff810fac10>] ? might_fault+0x5c/0xac [<ffffffff8114040b>] ? alloc_fd+0x3b/0x17c [<ffffffff8107fc2a>] ? lock_release+0x19a/0x1a6 [<ffffffff8114053a>] ? alloc_fd+0x16a/0x17c [<ffffffff81129e11>] do_sys_open+0x60/0xfc [<ffffffff8149aca2>] ? trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff81129ecd>] sys_open+0x20/0x22 [<ffffffff81009cb2>] system_call_fastpath+0x16/0x1b Code: df 31 c0 e8 e6 40 f7 ff 48 c7 c6 90 19 2a a0 48 89 df 31 c0 e8 d5 40 f7 ff 49 8b 84 24 f0 00 00 00 48 c7 c6 97 19 2a a0 48 89 df <48> 8b 50 08 31 c0 e8 b8 40 f7 ff 49 8b 84 24 f8 00 00 00 48 c7 RIP [<ffffffffa0296742>] snd_pcm_substream_proc_status_read+0x164/0x1ad [snd_pcm] RSP <ffff8801178c1b58> ---[ end trace 96389f116dd90473 ]---

Faulting insn: 48 8b 50 08 mov 0x8(%rax),%rdx

RAX: 6b6b6b6b6b6b6b6b

sound/core/pcm.c:453:

snd_iprintf(buffer, "hw_ptr : %ld\n", runtime->status->hw_ptr);

runtime = 0x6b6b6b6b6b6b6b6b

The code checks for NULL before using it, but this is a poison value.

Looks like a race. Could you check whether the patch below fixes the problem?

thanks,

Takashi

--- diff --git a/sound/core/pcm.c b/sound/core/pcm.c index 204af48..ac242a3 100644 --- a/sound/core/pcm.c +++ b/sound/core/pcm.c @@ -372,14 +372,17 @@ static void snd_pcm_substream_proc_hw_params_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer) { struct snd_pcm_substream *substream = entry->private_data; - struct snd_pcm_runtime *runtime = substream->runtime; + struct snd_pcm_runtime *runtime; + + mutex_lock(&substream->pcm->open_mutex); + runtime = substream->runtime; if (!runtime) { snd_iprintf(buffer, "closed\n"); - return; + goto unlock; } if (runtime->status->state == SNDRV_PCM_STATE_OPEN) { snd_iprintf(buffer, "no setup\n"); - return; + goto unlock; } snd_iprintf(buffer, "access: %s\n", snd_pcm_access_name(runtime->access)); snd_iprintf(buffer, "format: %s\n", snd_pcm_format_name(runtime->format)); @@ -398,20 +401,25 @@ static void snd_pcm_substream_proc_hw_params_read(struct snd_info_entry *entry, snd_iprintf(buffer, "OSS period frames: %lu\n", (unsigned long)runtime->oss.period_frames); } #endif + unlock: + mutex_unlock(&substream->pcm->open_mutex); }

static void snd_pcm_substream_proc_sw_params_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer) { struct snd_pcm_substream *substream = entry->private_data; - struct snd_pcm_runtime *runtime = substream->runtime; + struct snd_pcm_runtime *runtime; + + mutex_lock(&substream->pcm->open_mutex); + runtime = substream->runtime; if (!runtime) { snd_iprintf(buffer, "closed\n"); - return; + goto unlock; } if (runtime->status->state == SNDRV_PCM_STATE_OPEN) { snd_iprintf(buffer, "no setup\n"); - return; + goto unlock; } snd_iprintf(buffer, "tstamp_mode: %s\n", snd_pcm_tstamp_mode_name(runtime->tstamp_mode)); snd_iprintf(buffer, "period_step: %u\n", runtime->period_step); @@ -421,24 +429,29 @@ static void snd_pcm_substream_proc_sw_params_read(struct snd_info_entry *entry, snd_iprintf(buffer, "silence_threshold: %lu\n", runtime->silence_threshold); snd_iprintf(buffer, "silence_size: %lu\n", runtime->silence_size); snd_iprintf(buffer, "boundary: %lu\n", runtime->boundary); + unlock: + mutex_unlock(&substream->pcm->open_mutex); }

static void snd_pcm_substream_proc_status_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer) { struct snd_pcm_substream *substream = entry->private_data; - struct snd_pcm_runtime *runtime = substream->runtime; + struct snd_pcm_runtime *runtime; struct snd_pcm_status status; int err; + + mutex_lock(&substream->pcm->open_mutex); + runtime = substream->runtime; if (!runtime) { snd_iprintf(buffer, "closed\n"); - return; + goto unlock; } memset(&status, 0, sizeof(status)); err = snd_pcm_status(substream, &status); if (err < 0) { snd_iprintf(buffer, "error %d\n", err); - return; + goto unlock; } snd_iprintf(buffer, "state: %s\n", snd_pcm_state_name(status.state)); snd_iprintf(buffer, "owner_pid : %d\n", pid_vnr(substream->pid)); @@ -452,6 +465,8 @@ static void snd_pcm_substream_proc_status_read(struct snd_info_entry *entry, snd_iprintf(buffer, "-----\n"); snd_iprintf(buffer, "hw_ptr : %ld\n", runtime->status->hw_ptr); snd_iprintf(buffer, "appl_ptr : %ld\n", runtime->control->appl_ptr); + unlock: + mutex_unlock(&substream->pcm->open_mutex); }

#ifdef CONFIG_SND_PCM_XRUN_DEBUG