Message-ID: <000000000000cb5a8d0616f8872d@google.com>
Date: Thu, 25 Apr 2024 21:42:26 -0700
From: syzbot <syzbot+159077b1355b8cd72757@...kaller.appspotmail.com>
To: dmitry.torokhov@...il.com, linux-ext4@...r.kernel.org, 
	linux-fsdevel@...r.kernel.org, linux-input@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [input?] [ext4?] possible deadlock in uinput_request_submit

Hello,

syzbot found the following issue on:

HEAD commit:    7b4f2bc91c15 Add linux-next specific files for 20240418
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=12a07f67180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ae644165a243bf62
dashboard link: https://syzkaller.appspot.com/bug?extid=159077b1355b8cd72757
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1273c763180000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14b59430980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/524a18e6c5be/disk-7b4f2bc9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/029f1b84d653/vmlinux-7b4f2bc9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c02d1542e886/bzImage-7b4f2bc9.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/95b3c106e235/mount_6.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+159077b1355b8cd72757@...kaller.appspotmail.com

WARNING: possible circular locking dependency detected
6.9.0-rc4-next-20240418-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor109/5116 is trying to acquire lock:
ffff8880117e3870 (&newdev->mutex){+.+.}-{3:3}, at: uinput_request_send drivers/input/misc/uinput.c:151 [inline]
ffff8880117e3870 (&newdev->mutex){+.+.}-{3:3}, at: uinput_request_submit+0x19c/0x740 drivers/input/misc/uinput.c:182

but task is already holding lock:
ffff888015fb60b0
 (&ff->mutex
){+.+.}-{3:3}
, at: input_ff_upload+0x3e4/0xb00 drivers/input/ff-core.c:120

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (
&ff->mutex){+.+.}-{3:3}
:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       input_ff_flush+0x5e/0x140 drivers/input/ff-core.c:240
       input_flush_device+0x9c/0xc0 drivers/input/input.c:686
       evdev_release+0xf9/0x7d0 drivers/input/evdev.c:444
       __fput+0x406/0x8b0 fs/file_table.c:422
       __do_sys_close fs/open.c:1555 [inline]
       __se_sys_close fs/open.c:1540 [inline]
       __x64_sys_close+0x7f/0x110 fs/open.c:1540
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (
&dev->mutex
#2){+.+.}-{3:3}
:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       input_register_handle+0x6d/0x3b0 drivers/input/input.c:2555
       kbd_connect+0xbf/0x130 drivers/tty/vt/keyboard.c:1589
       input_attach_handler drivers/input/input.c:1064 [inline]
       input_register_device+0xcfa/0x1090 drivers/input/input.c:2396
       acpi_button_add+0x6c6/0xb90 drivers/acpi/button.c:604
       acpi_device_probe+0xa5/0x2b0 drivers/acpi/bus.c:1063
       really_probe+0x2b8/0xad0 drivers/base/dd.c:656
       __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:798
       driver_probe_device+0x50/0x430 drivers/base/dd.c:828
       __driver_attach+0x45f/0x710 drivers/base/dd.c:1214
       bus_for_each_dev+0x239/0x2b0 drivers/base/bus.c:368
       bus_add_driver+0x346/0x670 drivers/base/bus.c:673
       driver_register+0x23a/0x320 drivers/base/driver.c:246
       do_one_initcall+0x248/0x880 init/main.c:1263
       do_initcall_level+0x157/0x210 init/main.c:1325
       do_initcalls+0x3f/0x80 init/main.c:1341
       kernel_init_freeable+0x435/0x5d0 init/main.c:1574
       kernel_init+0x1d/0x2b0 init/main.c:1463
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #1 (
input_mutex){+.+.}-{3:3}
:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       input_register_device+0xae5/0x1090 drivers/input/input.c:2389
       uinput_create_device+0x40e/0x630 drivers/input/misc/uinput.c:365
       uinput_ioctl_handler+0x48b/0x1770 drivers/input/misc/uinput.c:904
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:907 [inline]
       __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0
 (&newdev->mutex
){+.+.}-{3:3}
:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
       __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __mutex_lock_common kernel/locking/mutex.c:608 [inline]
       __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
       uinput_request_send drivers/input/misc/uinput.c:151 [inline]
       uinput_request_submit+0x19c/0x740 drivers/input/misc/uinput.c:182
       uinput_dev_upload_effect+0x199/0x240 drivers/input/misc/uinput.c:257
       input_ff_upload+0x5df/0xb00 drivers/input/ff-core.c:150
       evdev_do_ioctl drivers/input/evdev.c:1183 [inline]
       evdev_ioctl_handler+0x17d0/0x21b0 drivers/input/evdev.c:1272
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:907 [inline]
       __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &newdev->mutex
 --> &dev->mutex
#2 --> 
&ff->mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(
&ff->mutex);
                               lock(&dev->mutex
#2);
                               lock(&ff->mutex
);
  lock(&newdev->mutex
);

 *** DEADLOCK ***

2 locks held by syz-executor109/5116:
 #0: ffff88801cac6110
 (&evdev->mutex
){+.+.}-{3:3}
, at: evdev_ioctl_handler+0x125/0x21b0 drivers/input/evdev.c:1263
 #1: ffff888015fb60b0
 (&ff->mutex
){+.+.}-{3:3}


---
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