WARNING in usbtouch_open

WARNING in usbtouch_open

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    7f7867ff usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=1503f4ec600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=792eb47789f57810
dashboard link: https://syzkaller.appspot.com/bug?extid=199ea16c7f26418b4365
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=173e4442600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=115482b2600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+199ea16c7f26418b4365@syzkaller.appspotmail.com

------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(lock->magic != lock)
WARNING: CPU: 0 PID: 1724 at kernel/locking/mutex.c:912 __mutex_lock_common  
kernel/locking/mutex.c:912 [inline]
WARNING: CPU: 0 PID: 1724 at kernel/locking/mutex.c:912  
__mutex_lock+0xd31/0x1360 kernel/locking/mutex.c:1077
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 1724 Comm: syz-executor025 Not tainted 5.3.0-rc2+ #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0xca/0x13e lib/dump_stack.c:113
  panic+0x2a3/0x6da kernel/panic.c:219
  __warn.cold+0x20/0x4a kernel/panic.c:576
  report_bug+0x262/0x2a0 lib/bug.c:186
  fixup_bug arch/x86/kernel/traps.c:179 [inline]
  fixup_bug arch/x86/kernel/traps.c:174 [inline]
  do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
  do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
  invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:912 [inline]
RIP: 0010:__mutex_lock+0xd31/0x1360 kernel/locking/mutex.c:1077
Code: d2 0f 85 f6 05 00 00 44 8b 05 bb 99 0a 02 45 85 c0 0f 85 0a f4 ff ff  
48 c7 c6 00 87 a6 85 48 c7 c7 a0 84 a6 85 e8 f4 24 b8 fb <0f> 0b e9 f0 f3  
ff ff 65 48 8b 1c 25 00 ef 01 00 be 08 00 00 00 48
RSP: 0018:ffff8881d29cf740 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff812830fd RDI: ffffed103a539eda
RBP: ffff8881d29cf8b0 R08: ffff8881d3e84800 R09: fffffbfff0d5eb25
R10: fffffbfff0d5eb24 R11: ffffffff86af5923 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff8881d33cdbc8 R15: ffff8881d3e97140
  usbtouch_open+0x101/0x310 drivers/input/touchscreen/usbtouchscreen.c:1537
  input_open_device+0x170/0x280 drivers/input/input.c:607
  evdev_open_device drivers/input/evdev.c:433 [inline]
  evdev_open+0x3fe/0x510 drivers/input/evdev.c:518
  chrdev_open+0x219/0x5c0 fs/char_dev.c:414
  do_dentry_open+0x494/0x1120 fs/open.c:797
  do_last fs/namei.c:3416 [inline]
  path_openat+0x1430/0x3f50 fs/namei.c:3533
  do_filp_open+0x1a1/0x280 fs/namei.c:3563
  do_sys_open+0x3c0/0x580 fs/open.c:1089
  do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4011f0
Code: 01 f0 ff ff 0f 83 00 0b 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f  
44 00 00 83 3d 9d 4b 2d 00 00 75 14 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 d4 0a 00 00 c3 48 83 ec 08 e8 3a 00 00 00
RSP: 002b:00007ffc88d90d38 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000124 RCX: 00000000004011f0
RDX: 0000000000000000 RSI: 0000000000020000 RDI: 00007ffc88d90d40
RBP: 6666666666666667 R08: 000000000000000f R09: 0000000000000023
R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000402150
R13: 00000000004021e0 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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Re: WARNING in usbtouch_open

[Oliver Neukum]

Am Montag, den 29.07.2019, 09:38 -0700 schrieb syzbot:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    7f7867ff usb-fuzzer: main usb gadget fuzzer driver
> git tree:       https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=1503f4ec600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=792eb47789f57810
> dashboard link: https://syzkaller.appspot.com/bug?extid=199ea16c7f26418b4365
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=173e4442600000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=115482b2600000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+199ea16c7f26418b4365@syzkaller.appspotmail.com

#syz test: https://github.com/google/kasan.git usb-fuzzer

From 29b755588bd353d0e10ae384c2c551dffa1b3e7b Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@suse.com>
Date: Tue, 30 Jul 2019 12:00:27 +0200
Subject: [PATCH] usbtouchscreen: add proper initialization

Mutexes shall be initialized before they are used.

Fixes: 12e510dbc57b2 ("Input: usbtouchscreen - fix deadlock in autosuspend")
Reported-by: syzbot+199ea16c7f26418b4365@syzkaller.appspotmail.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/input/touchscreen/usbtouchscreen.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c
index a2cec6cacf57..caacf211f51b 100644
--- a/drivers/input/touchscreen/usbtouchscreen.c
+++ b/drivers/input/touchscreen/usbtouchscreen.c
@@ -1658,6 +1658,7 @@ static int usbtouch_probe(struct usb_interface *intf,
 	input_dev = input_allocate_device();
 	if (!usbtouch || !input_dev)
 		goto out_free;
+	mutex_init(&usbtouch->pm_mutex);
 
 	type = &usbtouch_dev_info[id->driver_info];
 	usbtouch->type = type;
-- 
2.16.4

Re: WARNING in usbtouch_open

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger  
crash:

Reported-and-tested-by:  
syzbot+199ea16c7f26418b4365@syzkaller.appspotmail.com

Tested on:

commit:         7f7867ff usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan.git usb-fuzzer
kernel config:  https://syzkaller.appspot.com/x/.config?x=792eb47789f57810
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1347ab44600000

Note: testing is done by a robot and is best-effort only.