Re: USB Sound oops in Linus's latest tree

Shuah Khan
2016-03-18T23:00:35Z

On Fri, Mar 18, 2016 at 4:26 PM,
Greg KH <gregkh@linuxfoundation.org> wrote:
> Hi,
>
> I'm getting the following oops with my USB sound device using Linus's
> latest tree of the moment, which has the sound tree pull in it. Anyone
> seen this before?
>

Hi Greg,

Nicolai Stange sent in a fix for this problem - I can't find the link to this.
It is coming in through Linux Media tree.

thanks,
-- Shuah

The patch:

With commit

aebb2b89bff0 ("[media] sound/usb: Use Media Controller API to share
media resources")

an access to quirk->media_device without checking for quirk != NULL has
been introduced in usb_audio_probe().

With a Plantronics USB headset (device ID 0x047f:0xc010) attached,
this results in the following splat at boot time:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000014
IP: [<ffffffffa089aa6c>] usb_audio_probe+0x2cc/0x9a0 [snd_usb_audio]
Oops: 0000 [#1] SMP
[...]
CPU: 2 PID: 696 Comm: systemd-udevd Not tainted 4.5.0-next-20160315 #13
Hardware name: Dell Inc. Latitude E6540/0725FP, BIOS A10 06/26/2014
task: ffff88021c88d7c0 ti: ffff88003d5b0000 task.ti: ffff88003d5b0000
RIP: 0010:[<ffffffffa089aa6c>] [<ffffffffa089aa6c>]
usb_audio_probe+0x2cc/0x9a0 [snd_usb_audio]
[...]
Call Trace:
[<ffffffff815a8e16>] usb_probe_interface+0x136/0x2d0
[<ffffffff81509edc>] driver_probe_device+0x22c/0x440
[<ffffffff8150a1c1>] __driver_attach+0xd1/0xf0
[<ffffffff8150a0f0>] ? driver_probe_device+0x440/0x440
[<ffffffff815077ec>] bus_for_each_dev+0x6c/0xc0
[<ffffffff815095ce>] driver_attach+0x1e/0x20
[<ffffffff81509013>] bus_add_driver+0x1c3/0x280
[<ffffffff8150ab10>] driver_register+0x60/0xe0
[<ffffffff815a7711>] usb_register_driver+0x81/0x140
[<ffffffffa08c7000>] ? 0xffffffffa08c7000
[<ffffffffa08c701e>] usb_audio_driver_init+0x1e/0x1000 [snd_usb_audio]
[<ffffffff81002123>] do_one_initcall+0xb3/0x1f0
[<ffffffff811fb091>] ? __vunmap+0x81/0xd0
[<ffffffff8121b8d2>] ? kmem_cache_alloc_trace+0x182/0x1d0
[<ffffffff811b0267>] ? do_init_module+0x27/0x1d8
[<ffffffff811b029f>] do_init_module+0x5f/0x1d8
[<ffffffff8112ce35>] load_module+0x1fe5/0x27a0
[<ffffffff81129870>] ? __symbol_put+0x60/0x60
[<ffffffff81241690>] ? vfs_read+0x110/0x130
[<ffffffff8112d866>] SYSC_finit_module+0xe6/0x120
[<ffffffff8112d8be>] SyS_finit_module+0xe/0x10
[<ffffffff81003d94>] do_syscall_64+0x64/0x110
[<ffffffff817c0b61>] entry_SYSCALL64_slow_path+0x25/0x25

After encountering this, the system-udevd process seems to be blocked
until it is killed when hitting its timeout of 3min.

In analogy to the other accesses to members of quirk in usb_audio_probe(),
check for quirk != NULL before accessing its ->media_device.

Fixes: aebb2b89bff0 ("[media] sound/usb: Use Media Controller API to share
media resources")
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
---
Applicable to linux-next-20160315.

sound/usb/card.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 63244bb..479621e 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -612,7 +612,7 @@ static int usb_audio_probe(struct usb_interface *intf,
if (err < 0)
goto __error;

- if (quirk->media_device) {
+ if (quirk && quirk->media_device) {
/* don't want to fail when media_snd_device_create() fails */
media_snd_device_create(chip, intf);
}
--
2.7.2

>
> [ +0.002298] input: Schiit Audio USB Modi Device as /devices/pci0000:00/0000:00:14.0/usb2/2-10/2-10.1/2-10.1:1.2/0003:0D8C:1319.0001/input/input17
> [ +0.000056] hid-generic 0003:0D8C:1319.0001: input,hidraw0: USB HID v1.00 Device [Schiit Audio USB Modi Device] on usb-0000:00:14.0-10.1/input2
> [ +0.008749] BUG: unable to handle kernel NULL pointer dereference at 0000000000000014
> [ +0.001151] IP: [<ffffffffc0e79921>] usb_audio_probe+0x1e1/0x8f0 [snd_usb_audio]
> [ +0.001142] PGD 0
> [ +0.001114] Oops: 0000 [#1] PREEMPT SMP
> [ +0.001115] Modules linked in: snd_usb_audio(+) hid_generic snd_usbmidi_lib usbhid snd_rawmidi snd_seq_device hid media arc4 fuse btusb btrtl btbcm btintel bluetooth rt2800usb rt2x00usb rt2800lib rt2x00lib mac80211 crc_ccitt cfg80211 rfkill nls_cp437 vfat fat iTCO_wdt iTCO_vendor_support mxm_wmi x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pclmul crct10dif_common crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel aes_x86_64 glue_helper lrw gf128mul ablk_helper cryptd psmouse serio_raw pcspkr firewire_ohci firewire_core crc_itu_t xhci_pci ehci_pci xhci_hcd ehci_hcd mei_me usbcore mei lpc_ich mfd_core usb_common wmi evdev ip_tables x_tables
> [ +0.004079] CPU: 4 PID: 615 Comm: systemd-udevd Not tainted 4.6.0-rc1+ #103
> [ +0.001382] Hardware name: / , BIOS KLZ8711D.86A.0457.2015.0713.1319 07/13/2015
> [ +0.001387] task: ffff880098ec0e00 ti: ffff880251920000 task.ti: ffff880251920000
> [ +0.001417] RIP: 0010:[<ffffffffc0e79921>] [<ffffffffc0e79921>] usb_audio_probe+0x1e1/0x8f0 [snd_usb_audio]
> [ +0.001414] RSP: 0018:ffff880251923af0 EFLAGS: 00010246
> [ +0.001409] RAX: 0000000000000000 RBX: ffff88024d602000 RCX: 0000000000000000
> [ +0.001404] RDX: ffff880254e0b340 RSI: ffff8802559b99f8 RDI: ffffffff82181030
> [ +0.001413] RBP: ffff880251923b50 R08: 0000000000019d00 R09: ffffffff81385837
> [ +0.001431] R10: ffffea0009461200 R11: ffff880253b3fe72 R12: 0000000000000000
> [ +0.001411] R13: 0000000000000000 R14: 0000000000000001 R15: ffff88025338c212
> [ +0.001436] FS: 00007f7a8db567c0(0000) GS:ffff88025fb00000(0000) knlGS:0000000000000000
> [ +0.001431] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ +0.001445] CR2: 0000000000000014 CR3: 0000000251854000 CR4: 00000000001406e0
> [ +0.001451] Stack:
> [ +0.001433] ffff880253302e88 ffff88024d602054 ffff88009879d000 ffff880253302e88
> [ +0.001480] ffff880255f7e000 386430425355d030 ff00393133313a63 ffff8800984f4098
> [ +0.001466] ffff8800984f4000 ffffffffc0e95728 ffff88009879d030 ffffffffc0e955a0
> [ +0.001497] Call Trace:
> [ +0.001295] [<ffffffffc0067cfd>] usb_probe_interface+0x1bd/0x300 [usbcore]
> [ +0.001427] [<ffffffff815987e9>] driver_probe_device+0x249/0x450
> [ +0.001400] [<ffffffff81598a74>] __driver_attach+0x84/0x90
> [ +0.001398] [<ffffffff815989f0>] ? driver_probe_device+0x450/0x450
> [ +0.001417] [<ffffffff815963e4>] bus_for_each_dev+0x64/0xa0
> [ +0.001369] [<ffffffff81597ede>] driver_attach+0x1e/0x20
> [ +0.001396] [<ffffffff815979ab>] bus_add_driver+0x1eb/0x280
> [ +0.001365] [<ffffffff81599390>] driver_register+0x60/0xe0
> [ +0.001369] [<ffffffffc0066834>] usb_register_driver+0x84/0x140 [usbcore]
> [ +0.001422] [<ffffffffc0e9d000>] ? 0xffffffffc0e9d000
> [ +0.001370] [<ffffffffc0e9d01e>] usb_audio_driver_init+0x1e/0x20 [snd_usb_audio]
> [ +0.001472] [<ffffffff8100211b>] do_one_initcall+0xab/0x1d0
> [ +0.001547] [<ffffffff8115e732>] do_init_module+0x5f/0x1cd
> [ +0.001469] [<ffffffff810f9ec8>] load_module+0x1368/0x1510
> [ +0.001542] [<ffffffff810f75d0>] ? symbol_put_addr+0x50/0x50
> [ +0.001468] [<ffffffff810fa2a8>] SyS_finit_module+0xc8/0xf0
> [ +0.001451] [<ffffffff81003c6e>] do_syscall_64+0x5e/0xc0
> [ +0.001538] [<ffffffff817fb425>] entry_SYSCALL64_slow_path+0x25/0x25
> [ +0.001397] Code: f8 01 00 44 89 e6 48 89 df e8 dc 73 00 00 85 c0 89 c1 0f 88 99 00 00 00 48 8b 7b 10 e8 c9 0b 80 c0 85 c0 89 c1 0f 88 86 00 00 00 <41> 80 7d 14 00 0f 85 90 04 00 00 48 63 03 48 89 1c c5 40 90 e9
> [ +0.001513] RIP [<ffffffffc0e79921>] usb_audio_probe+0x1e1/0x8f0 [snd_usb_audio]
> [ +0.001468] RSP <ffff880251923af0>
> [ +0.001576] CR2: 0000000000000014
> [ +0.010610] ---[ end trace c9cdd61401b8f1d9 ]---