On Mon, 09 Oct 2017 14:39:44 +0200,
Andrey Konovalov wrote:
>
> On Mon, Oct 9, 2017 at 2:31 PM, Takashi Iwai <tiwai@xxxxxxx> wrote:
> > On Mon, 09 Oct 2017 12:58:59 +0200,
> > Andrey Konovalov wrote:
> >>
> >> On Tue, Oct 3, 2017 at 9:41 AM, Takashi Iwai <tiwai@xxxxxxx> wrote:
> >> > On Mon, 25 Sep 2017 14:40:08 +0200,
> >> > Andrey Konovalov wrote:
> >> >>
> >> >> Hi!
> >> >>
> >> >> I've got the following report while fuzzing the kernel with syzkaller.
> >> >>
> >> >> On commit e19b205be43d11bff638cad4487008c48d21c103 (4.14-rc2).
> >> >>
> >> >> INFO: trying to register non-static key.
> >> >> the code is fine but needs lockdep annotation.
> >> >> turning off the locking correctness validator.
> >> >> CPU: 1 PID: 1845 Comm: kworker/1:2 Not tainted
> >> >> 4.14.0-rc2-42613-g1488251d1a98 #238
> >> >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> >> >> Workqueue: usb_hub_wq hub_event
> >> >> Call Trace:
> >> >> __dump_stack lib/dump_stack.c:16
> >> >> dump_stack+0x292/0x395 lib/dump_stack.c:52
> >> >> register_lock_class+0x6c4/0x1a00 kernel/locking/lockdep.c:769
> >> >> __lock_acquire+0x27e/0x4550 kernel/locking/lockdep.c:3385
> >> >> lock_acquire+0x259/0x620 kernel/locking/lockdep.c:4002
> >> >> del_timer_sync+0x12c/0x280 kernel/time/timer.c:1237
> >> >> podhd_disconnect+0x8c/0x160 sound/usb/line6/podhd.c:299
> >> >> line6_probe+0x844/0x1310 sound/usb/line6/driver.c:783
> >> >> podhd_probe+0x64/0x70 sound/usb/line6/podhd.c:474
> >> >> usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361
> >> >> really_probe drivers/base/dd.c:413
> >> >> driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
> >> >> __device_attach_driver+0x230/0x290 drivers/base/dd.c:653
> >> >> bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
> >> >> __device_attach+0x26e/0x3d0 drivers/base/dd.c:710
> >> >> device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
> >> >> bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
> >> >> device_add+0xd0b/0x1660 drivers/base/core.c:1835
> >> >> usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932
> >> >> generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174
> >> >> usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266
> >> >> really_probe drivers/base/dd.c:413
> >> >> driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
> >> >> __device_attach_driver+0x230/0x290 drivers/base/dd.c:653
> >> >> bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
> >> >> __device_attach+0x26e/0x3d0 drivers/base/dd.c:710
> >> >> device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
> >> >> bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
> >> >> device_add+0xd0b/0x1660 drivers/base/core.c:1835
> >> >> usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457
> >> >> hub_port_connect drivers/usb/core/hub.c:4903
> >> >> hub_port_connect_change drivers/usb/core/hub.c:5009
> >> >> port_event drivers/usb/core/hub.c:5115
> >> >> hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195
> >> >> process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119
> >> >> worker_thread+0x221/0x1850 kernel/workqueue.c:2253
> >> >> kthread+0x3a1/0x470 kernel/kthread.c:231
> >> >> ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
> >> >
> >> > This looks like an access to the uninitialized timer object.
> >> > Could you check the patch below whether it fixes the issue?
> >> > Thanks!
> >> >
> >> >
> >> > Takashi
> >>
> >> Hi Takashi,
> >>
> >> I've applied your patch and now get GPF on
> >> usb_driver_release_interface(&podhd_driver, intf):
> >
> > Another day, another Oops... The patch below should cover it.
> > I'm going to queue both now.
>
> With these two patches I get:
>
> kasan: CONFIG_KASAN_INLINE enabled
> kasan: GPF could be caused by NULL-ptr deref or user memory access
> general protection fault: 0000 [#1] PREEMPT SMP KASAN
> Modules linked in:
> CPU: 1 PID: 0 Comm: swapper/1 Not tainted
> 4.14.0-rc4-43414-g3c9155515146-dirty #372
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> task: ffff88006baa3180 task.stack: ffff88006bac0000
> RIP: 0010:usb_fill_bulk_urb ./include/linux/usb.h:1619
> RIP: 0010:line6_start_listen+0x3fe/0x9e0 sound/usb/line6/driver.c:76
Sight, is tonight a full-moon?
This is another bug, an overlook in the error handling.
The fix patch is below.
thanks,
Takashi
-- 8< --
From: Takashi Iwai <tiwai@xxxxxxx>
Subject: [PATCH] ALSA: line6: Fix leftover URB at error-path during probe
While line6_probe() may kick off URB for a control MIDI endpoint, the
function doesn't clean up it properly at its error path. This results
in a leftover URB action that is eventually triggered later and causes
an Oops like:
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 0 Comm: swapper/1 Not tainted
RIP: 0010:usb_fill_bulk_urb ./include/linux/usb.h:1619
RIP: 0010:line6_start_listen+0x3fe/0x9e0 sound/usb/line6/driver.c:76
Call Trace:
<IRQ>
line6_data_received+0x1f7/0x470 sound/usb/line6/driver.c:326
__usb_hcd_giveback_urb+0x2e0/0x650 drivers/usb/core/hcd.c:1779
usb_hcd_giveback_urb+0x337/0x420 drivers/usb/core/hcd.c:1845
dummy_timer+0xba9/0x39f0 drivers/usb/gadget/udc/dummy_hcd.c:1965
call_timer_fn+0x2a2/0x940 kernel/time/timer.c:1281
....
Since the whole clean-up procedure is done in line6_disconnect()
callback, we can simply call it in the error path instead of
open-coding the whole again. It'll fix such an issue automagically.
The bug was spotted by syzkaller.
Fixes: eedd0e95d355 ("ALSA: line6: Don't forget to call driver's destructor at error path")
Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
sound/usb/line6/driver.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
index 0ff5a7d2e19f..c8f723c3a033 100644
--- a/sound/usb/line6/driver.c
+++ b/sound/usb/line6/driver.c
@@ -779,9 +779,10 @@ int line6_probe(struct usb_interface *interface,
return 0;
error:
- if (line6->disconnect)
- line6->disconnect(line6);
- snd_card_free(card);
+ /* we can call disconnect callback here because no close-sync is
+ * needed yet at this point
+ */
+ line6_disconnect(interface);
return ret;
}
EXPORT_SYMBOL_GPL(line6_probe);
--
2.14.2
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