Re: [linux-pm] [2.6.36-rc4/HEAD] unable to handle kernel NULL pointer dereference (plist_add)
From: Rafael J. Wysocki
Date: Tue Sep 14 2010 - 18:07:34 EST
On Tuesday, September 14, 2010, Rafael J. Wysocki wrote:
> On Monday, September 13, 2010, Simon Kirby wrote:
> > Hi!
> >
> > At first I thought I hitting a suspend bug, but it was because I had an
> > rmmod/modprobe of snd_ice1724 in my "gosleep" script to work around my
> > sound sounding crackly after resume. I can reproduce this same crash
> > simply by using sound, rmmod snd_ice1724, modprobe snd_ice1724, and then
> > using sound again.
> >
> > I git-bisected to:
> > 82f682514a5df89ffb3890627eebf0897b7a84ec is the first bad commit
> > commit 82f682514a5df89ffb3890627eebf0897b7a84ec
> > Author: James Bottomley <James.Bottomley@xxxxxxx>
> > Date: Mon Jul 5 22:53:06 2010 +0200
> >
> > pm_qos: Get rid of the allocation in pm_qos_add_request()
> >
> > All current users of pm_qos_add_request() have the ability to supply
> > the memory required by the pm_qos routines, so make them do this and
> > eliminate the kmalloc() with pm_qos_add_request(). This has the
> > double benefit of making the call never fail and allowing it to be
> > called from atomic context.
> >
> > Signed-off-by: James Bottomley <James.Bottomley@xxxxxxx>
> > Signed-off-by: mark gross <markgross@xxxxxxxxxxx>
> > Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
> >
> > :040000 040000 0370d037cfe56ae4079bc47713b98c5961de258f 92d6437da54649496c84bacc16ef4b17f8087bbd M drivers
> > :040000 040000 6ec551133758633de70e97b4a41d893a5c050e74 4ac17ea227c07d9cf7dae297a40bbbcc374c232f M include
> > :040000 040000 d0bb4b15e77a0976940af48588ef0e9b9fd7590b ac682974217c7e75a771b92c8efa7c83659d2916 M kernel
> > :040000 040000 9ab6e37ec622354cb93abc2b7424b10263bcd007 011680bad3da4b60aebb659eaeb85a037e2513f3 M sound
> >
> > ...but I can't revert this over HEAD due to conflicts and I can't see
> > what's wrong in the diff. 2.6.35 is fine.
> >
> > Simon-
> >
> > [ 61.234230] ICE1724 0000:01:06.0: PCI INT A disabled
> > [ 61.240010] ICE1724 0000:01:06.0: PCI INT A -> GSI 21 (level, low) -> IRQ 21
> > [ 62.156008] BUG: unable to handle kernel NULL pointer dereference at (null)
> > [ 62.156008] IP: [<ffffffff81379706>] plist_add+0x36/0xa0
> > [ 62.156008] PGD 1ad813067 PUD 1ad989067 PMD 0
> > [ 62.156008] Oops: 0000 [#1] SMP
> > [ 62.156008] last sysfs file: /sys/devices/pci0000:00/0000:00:14.4/0000:01:06.0/sound/card0/uevent
> > [ 62.156118] CPU 1
> > [ 62.156147] Modules linked in: snd_ice1724 sco bnep rfcomm l2cap bluetooth ppdev hwmon_vid usb_storage tun i2c_viapro snd_rawmidi snd_ice17xx_ak4xxx snd_ac97_codec ac97_bus snd_ak4xxx_adda snd_ak4114 snd_pt2258 snd_i2c parport_pc r8169 parport snd_ak4113 k10temp [last unloaded: snd_ice1724]
> > [ 62.156849]
> > [ 62.156925] Pid: 3053, comm: mplayer Not tainted 2.6.36-rc4-oof+ #6 M4A79T Deluxe/System Product Name
> > [ 62.157058] RIP: 0010:[<ffffffff81379706>] [<ffffffff81379706>] plist_add+0x36/0xa0
> > [ 62.157217] RSP: 0018:ffff8801ac7f3cd8 EFLAGS: 00010002
> > [ 62.157297] RAX: fffffffffffffff8 RBX: ffff8801a93eae40 RCX: ffff8801ac48e048
> > [ 62.157386] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801a93eae40
> > [ 62.157475] RBP: ffff8801ac7f3cf8 R08: 0000000000005356 R09: 0000000000004000
> > [ 62.157564] R10: 0000000000000000 R11: 00000000fffffffe R12: ffffffff8195a2a0
> > [ 62.157590] R13: ffff8801a93eae58 R14: 0000000000003e80 R15: ffffffff8195a2b0
> > [ 62.157590] FS: 00007f79749f5860(0000) GS:ffff880001c80000(0000) knlGS:0000000000000000
> > [ 62.157590] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 62.157590] CR2: 0000000000000000 CR3: 00000001aef63000 CR4: 00000000000006e0
> > [ 62.157590] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > [ 62.157590] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> > [ 62.157590] Process mplayer (pid: 3053, threadinfo ffff8801ac7f2000, task ffff8801ac535cd0)
> > [ 62.157590] Stack:
> > [ 62.157590] ffff8801ac7f3d18 ffffffff8195a2a0 ffff8801a93eae40 00000000ffffffff
> > [ 62.157590] <0> ffff8801ac7f3d48 ffffffff8105f35b ffff880100000000 0000000000000292
> > [ 62.157590] <0> ffff8801ac7f3d58 ffff8801a93eae40 ffff8801ad849400 ffff8801ad849c00
> > [ 62.157590] Call Trace:
> > [ 62.157590] [<ffffffff8105f35b>] update_target+0x12b/0x140
> > [ 62.157590] [<ffffffff8105f5aa>] pm_qos_add_request+0x4a/0x80
> > [ 62.157590] [<ffffffff8157e8a4>] snd_pcm_hw_params+0x2d4/0x3a0
> > [ 62.157590] [<ffffffff8157ed41>] snd_pcm_common_ioctl1+0xb1/0xb90
> > [ 62.157590] [<ffffffff810bcbc2>] ? handle_mm_fault+0x192/0xa50
> > [ 62.157590] [<ffffffff8157facd>] snd_pcm_playback_ioctl1+0x3d/0x220
> > [ 62.157590] [<ffffffff81698b9f>] ? do_page_fault+0x17f/0x440
> > [ 62.157590] [<ffffffff8158035d>] snd_pcm_playback_ioctl+0x3d/0x50
> > [ 62.157590] [<ffffffff810e8787>] do_vfs_ioctl+0x97/0x530
> > [ 62.157590] [<ffffffff810c493c>] ? do_mmap_pgoff+0x34c/0x3a0
> > [ 62.157590] [<ffffffff810e8c6a>] sys_ioctl+0x4a/0x80
> > [ 62.157590] [<ffffffff81002ceb>] system_call_fastpath+0x16/0x1b
> > [ 62.157590] Code: 54 49 89 f4 53 48 89 fb 48 83 ec 08 4c 3b 6f 18 75 69 49 8b 04 24 48 83 e8 08 eb 0f 90 8b 30 39 33 7c 18 66 90 74 4e 48 8d 42 f8 <48> 8b 50 08 48 8d 48 08 4c 39 e1 0f 18 0a 75 e2 48 8b 50 10 48
> > [ 62.157590] RIP [<ffffffff81379706>] plist_add+0x36/0xa0
> > [ 62.157590] RSP <ffff8801ac7f3cd8>
> > [ 62.157590] CR2: 0000000000000000
> > [ 62.157590] ---[ end trace 853ed59ac5273c1f ]---
>
> Hmm, interesting. This looks like a plist corruption to me, but can you please
> check (using gdb) what line of code corresponds to the address
> plist_add+0x36/0xa0 ?
Well, my current theory is that the list member of latency_pm_qos_req in
struct snd_pcm_substream gets corrupted because of the changed size of the
structure. Then, deleting it from the plist corrupts the plist itself, which
only turns up when we try to add a new item to it.
If that's really the case, the (untested!) patch below should help (unless I broke it).
Thanks,
Rafael
---
include/sound/pcm.h | 2 +-
sound/core/pcm_native.c | 40 +++++++++++++++++++++++++++++++++++-----
2 files changed, 36 insertions(+), 6 deletions(-)
Index: linux-2.6/include/sound/pcm.h
===================================================================
--- linux-2.6.orig/include/sound/pcm.h
+++ linux-2.6/include/sound/pcm.h
@@ -370,7 +370,7 @@ struct snd_pcm_substream {
int number;
char name[32]; /* substream name */
int stream; /* stream (direction) */
- struct pm_qos_request_list latency_pm_qos_req; /* pm_qos request */
+ struct pm_qos_request_list *latency_pm_qos_req; /* pm_qos request */
size_t buffer_bytes_max; /* limit ring buffer size */
struct snd_dma_buffer dma_buffer;
unsigned int dma_buf_id;
Index: linux-2.6/sound/core/pcm_native.c
===================================================================
--- linux-2.6.orig/sound/core/pcm_native.c
+++ linux-2.6/sound/core/pcm_native.c
@@ -369,6 +369,38 @@ static int period_to_usecs(struct snd_pc
return usecs;
}
+static void snd_pcm_add_pm_qos_request(struct snd_pcm_substream *substream,
+ int usecs)
+{
+ struct pm_qos_request_list *pm_qos_req;
+
+ if (substream->latency_pm_qos_req)
+ return;
+
+ pm_qos_req = kzalloc(sizeof(*pm_qos_req), GFP_KERNEL);
+ if (!pm_qos_req) {
+ snd_printd("failure to allocate PM QoS request object");
+ return;
+ }
+
+ pm_qos_add_request(pm_qos_req, PM_QOS_CPU_DMA_LATENCY, usecs);
+ substream->latency_pm_qos_req = pm_qos_req;
+}
+
+static void snd_pcm_remove_pm_qos_request(struct snd_pcm_substream *substream)
+{
+ struct pm_qos_request_list *pm_qos_req = substream->latency_pm_qos_req;
+
+ if (!pm_qos_req)
+ return;
+
+ if (pm_qos_request_active(pm_qos_req))
+ pm_qos_remove_request(pm_qos_req);
+ kfree(pm_qos_req);
+
+ substream->latency_pm_qos_req = NULL;
+}
+
static int snd_pcm_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params)
{
@@ -451,11 +483,9 @@ static int snd_pcm_hw_params(struct snd_
snd_pcm_timer_resolution_change(substream);
runtime->status->state = SNDRV_PCM_STATE_SETUP;
- if (pm_qos_request_active(&substream->latency_pm_qos_req))
- pm_qos_remove_request(&substream->latency_pm_qos_req);
+ snd_pcm_remove_pm_qos_request(substream);
if ((usecs = period_to_usecs(runtime)) >= 0)
- pm_qos_add_request(&substream->latency_pm_qos_req,
- PM_QOS_CPU_DMA_LATENCY, usecs);
+ snd_pcm_add_pm_qos_request(substream, usecs);
return 0;
_error:
/* hardware might be unuseable from this time,
@@ -510,7 +540,7 @@ static int snd_pcm_hw_free(struct snd_pc
if (substream->ops->hw_free)
result = substream->ops->hw_free(substream);
runtime->status->state = SNDRV_PCM_STATE_OPEN;
- pm_qos_remove_request(&substream->latency_pm_qos_req);
+ snd_pcm_remove_pm_qos_request(substream);
return result;
}
--
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