On Mon, 09 Oct 2017 14:39:44 +0200, Andrey Konovalov wrote:
On Mon, Oct 9, 2017 at 2:31 PM, Takashi Iwai tiwai@suse.de 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@suse.de 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@suse.de 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@google.com Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai tiwai@suse.de --- 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);