Re: usb/gadget: GPF in usb_gadget_unregister_driver

From: "Felix Hädicke" <felixhaedicke@web.de>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: linux-usb@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Felipe Balbi <balbi@kernel.org>
Subject: Re: usb/gadget: GPF in usb_gadget_unregister_driver
Date: Sat, 3 Dec 2016 18:31:39 +0100	[thread overview]
Message-ID: <6c5b6bf0-207f-2bba-35ff-c6c04017d158@web.de> (raw)
In-Reply-To: <CAAeHK+xNM+D8O-2x2BMnbessbFQgoJC-hs4a+2mWec2JhdXoAg@mail.gmail.com>

Hi,
> Hi!
>
> I've got the following error report while running the syzkaller fuzzer.
>
> On commit 3c49de52d5647cda8b42c4255cf8a29d1e22eff5 (Dec 2).
>
> general protection fault: 0000 [#1] SMP KASAN
> Dumping ftrace buffer:
>    (ftrace buffer empty)
> Modules linked in:
> CPU: 0 PID: 10564 Comm: syz-executor0 Not tainted 4.9.0-rc7+ #4
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> task: ffff88006cd0db40 task.stack: ffff88006a050000
> RIP: 0010:[<ffffffff8201aa9e>]  [<ffffffff8201aa9e>]
> __list_del_entry+0xce/0x280 lib/list_debug.c:57
> RSP: 0018:ffff88006a056ea8  EFLAGS: 00010246
> RAX: dffffc0000000000 RBX: 1ffff1000d40add6 RCX: ffffffff860ceac8
> RDX: 0000000000000000 RSI: ffff88006cd0e340 RDI: ffffffff860cead0
> RBP: ffff88006a056f38 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000006 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000000 R14: ffffffff860cea00 R15: ffff88006a056f10
> FS:  0000000000000000(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000000002000d000 CR3: 0000000005c1d000 CR4: 00000000000006f0
> Stack:
>  ffffffff859785e0 0000000041b58ab3 ffffffff8593717a ffffffff8201a9d0
>  1ffff1000d40ade0 ffff88006cd0db40 ffffffff817e5a3c ffff88006cd0e338
>  0000000000000a06 1ffff1000d40ade4 ffff88006cd0e340 0000000000000000
> Call Trace:
>  [<ffffffff8201ac5d>] list_del+0xd/0x70 lib/list_debug.c:77
>  [<ffffffff830ebf80>] usb_gadget_unregister_driver+0x120/0x240
> drivers/usb/gadget/udc/core.c:1365
>  [<ffffffff832245d0>] dev_release+0x80/0x160
> drivers/usb/gadget/legacy/inode.c:1187
>  [<ffffffff81805852>] __fput+0x332/0x7f0 fs/file_table.c:208
>  [<ffffffff81805d95>] ____fput+0x15/0x20 fs/file_table.c:244
>  [<ffffffff81338b9b>] task_work_run+0x19b/0x270 kernel/task_work.c:116
>  [<     inline     >] exit_task_work include/linux/task_work.h:21
>  [<ffffffff812c7eca>] do_exit+0x16aa/0x2530 kernel/exit.c:828
>  [<ffffffff812cd749>] do_group_exit+0x149/0x420 kernel/exit.c:932
>  [<ffffffff812faa9d>] get_signal+0x76d/0x17b0 kernel/signal.c:2307
>  [<ffffffff811cfee2>] do_signal+0xd2/0x2120 arch/x86/kernel/signal.c:807
>  [<ffffffff81003d00>] exit_to_usermode_loop+0x170/0x200
> arch/x86/entry/common.c:156
>  [<     inline     >] prepare_exit_to_usermode arch/x86/entry/common.c:190
>  [<ffffffff81007293>] syscall_return_slowpath+0x3d3/0x420
> arch/x86/entry/common.c:259
>  [<ffffffff84f47f62>] entry_SYSCALL_64_fastpath+0xc0/0xc2
> Code: c5 0f 84 e2 00 00 00 48 b8 00 02 00 00 00 00 ad de 49 39 c4 0f
> 84 ec 00 00 00 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80>
> 3c 02 00 0f 85 35 01 00 00 4d 8b 04 24 49 39 c8 0f 85 e1 00
> RIP  [<ffffffff8201aa9e>] __list_del_entry+0xce/0x280 lib/list_debug.c:57
>  RSP <ffff88006a056ea8>
> ---[ end trace 883f708e6720200f ]---
> Kernel panic - not syncing: Fatal exception
> Dumping ftrace buffer:
>    (ftrace buffer empty)
> Kernel Offset: disabled
> --
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Looks similar to the oops which I had reported a few days ago. See mail
"PROBLEM: Oops when unbinding an inactive gadget configfs configuration
from UDC". Maybe you want to test my bugfix proposal "usb: gadget: udc:
core: fix return code of usb_gadget_probe_driver()".

Regards,
Felix