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Subjectpossible deadlock in do_fcntl
From
Hello,

syzbot found the following issue on:

HEAD commit: d1d2220c Add linux-next specific files for 20200924
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17a0b98d900000
kernel config: https://syzkaller.appspot.com/x/.config?x=254e028a642027c
dashboard link: https://syzkaller.appspot.com/bug?extid=e6d5398a02c516ce5e70
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e6d5398a02c516ce5e70@syzkaller.appspotmail.com

========================================================
WARNING: possible irq lock inversion dependency detected
5.9.0-rc6-next-20200924-syzkaller #0 Not tainted
--------------------------------------------------------
syz-executor.4/9635 just changed the state of lock:
ffff8880884c38f8 (&f->f_owner.lock){.+..}-{2:2}, at: f_getown_ex fs/fcntl.c:206 [inline]
ffff8880884c38f8 (&f->f_owner.lock){.+..}-{2:2}, at: do_fcntl+0x8f6/0x10c0 fs/fcntl.c:387
but this lock was taken by another, HARDIRQ-safe lock in the past:
(&dev->event_lock){-...}-{2:2}


and interrupts could create inverse lock ordering between them.


other info that might help us debug this:
Chain exists of:
&dev->event_lock --> &new->fa_lock --> &f->f_owner.lock

Possible interrupt unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&f->f_owner.lock);
local_irq_disable();
lock(&dev->event_lock);
lock(&new->fa_lock);
<Interrupt>
lock(&dev->event_lock);

*** DEADLOCK ***

no locks held by syz-executor.4/9635.

the shortest dependencies between 2nd lock and 1st lock:
-> (&dev->event_lock){-...}-{2:2} {
IN-HARDIRQ-W at:
lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x94/0xd0 kernel/locking/spinlock.c:159
input_event drivers/input/input.c:440 [inline]
input_event+0x7b/0xb0 drivers/input/input.c:433
input_report_key include/linux/input.h:417 [inline]
psmouse_report_standard_buttons+0x2c/0x80 drivers/input/mouse/psmouse-base.c:123
psmouse_report_standard_packet drivers/input/mouse/psmouse-base.c:141 [inline]
psmouse_process_byte+0x1e1/0x890 drivers/input/mouse/psmouse-base.c:232
psmouse_handle_byte+0x41/0x1b0 drivers/input/mouse/psmouse-base.c:274
psmouse_interrupt+0x304/0xf00 drivers/input/mouse/psmouse-base.c:426
serio_interrupt+0x88/0x150 drivers/input/serio/serio.c:1002
i8042_interrupt+0x27a/0x520 drivers/input/serio/i8042.c:598
__handle_irq_event_percpu+0x20b/0x9e0 kernel/irq/handle.c:156
handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
handle_irq_event+0x102/0x290 kernel/irq/handle.c:213
handle_edge_irq+0x25f/0xd00 kernel/irq/chip.c:819
asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:786
__run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
handle_irq arch/x86/kernel/irq.c:230 [inline]
__common_interrupt arch/x86/kernel/irq.c:249 [inline]
common_interrupt+0x115/0x1f0 arch/x86/kernel/irq.c:239
asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:622
native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60
arch_safe_halt arch/x86/include/asm/paravirt.h:150 [inline]
acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
acpi_idle_do_entry+0x1e8/0x330 drivers/acpi/processor_idle.c:517
acpi_idle_enter+0x35a/0x550 drivers/acpi/processor_idle.c:648
cpuidle_enter_state+0x1ab/0xd20 drivers/cpuidle/cpuidle.c:237
cpuidle_enter+0x4a/0xa0 drivers/cpuidle/cpuidle.c:350
call_cpuidle kernel/sched/idle.c:132 [inline]
cpuidle_idle_call kernel/sched/idle.c:213 [inline]
do_idle+0x48e/0x730 kernel/sched/idle.c:273
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:369
start_kernel+0x490/0x4b1 init/main.c:1049
secondary_startup_64_no_verify+0xa6/0xab
INITIAL USE at:
lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x94/0xd0 kernel/locking/spinlock.c:159
input_inject_event+0xa6/0x310 drivers/input/input.c:466
__led_set_brightness drivers/leds/led-core.c:48 [inline]
led_set_brightness_nopm drivers/leds/led-core.c:275 [inline]
led_set_brightness_nosleep+0xe6/0x1a0 drivers/leds/led-core.c:292
led_set_brightness+0x134/0x170 drivers/leds/led-core.c:267
led_trigger_event drivers/leds/led-triggers.c:387 [inline]
led_trigger_event+0x70/0xd0 drivers/leds/led-triggers.c:377
kbd_led_trigger_activate+0xfa/0x130 drivers/tty/vt/keyboard.c:1005
led_trigger_set+0x61e/0xbd0 drivers/leds/led-triggers.c:195
led_trigger_set_default drivers/leds/led-triggers.c:259 [inline]
led_trigger_set_default+0x1a6/0x230 drivers/leds/led-triggers.c:246
led_classdev_register_ext+0x511/0x6a0 drivers/leds/led-class.c:412
led_classdev_register include/linux/leds.h:190 [inline]
input_leds_connect+0x3fb/0x740 drivers/input/input-leds.c:139
input_attach_handler+0x180/0x1f0 drivers/input/input.c:1031
input_register_device.cold+0xf0/0x243 drivers/input/input.c:2229
atkbd_connect+0x736/0x9d0 drivers/input/keyboard/atkbd.c:1293
serio_connect_driver drivers/input/serio/serio.c:47 [inline]
serio_driver_probe+0x72/0xa0 drivers/input/serio/serio.c:778
really_probe+0x282/0x9f0 drivers/base/dd.c:553
driver_probe_device+0xfe/0x1d0 drivers/base/dd.c:737
device_driver_attach+0x228/0x290 drivers/base/dd.c:1012
__driver_attach drivers/base/dd.c:1089 [inline]
__driver_attach+0xda/0x240 drivers/base/dd.c:1043
bus_for_each_dev+0x147/0x1d0 drivers/base/bus.c:305
serio_attach_driver drivers/input/serio/serio.c:808 [inline]
serio_handle_event+0x5f6/0xa30 drivers/input/serio/serio.c:227
process_one_work+0x933/0x15a0 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3af/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
}
... key at: [<ffffffff8e5f3e60>] __key.5+0x0/0x40
... acquired at:
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:354 [inline]
evdev_pass_values+0x195/0xa70 drivers/input/evdev.c:262
evdev_events+0x20c/0x330 drivers/input/evdev.c:307
input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
input_pass_values drivers/input/input.c:134 [inline]
input_handle_event+0x324/0x1400 drivers/input/input.c:399
input_inject_event+0x2f5/0x310 drivers/input/input.c:471
evdev_write+0x424/0x750 drivers/input/evdev.c:530
vfs_write+0x28e/0x700 fs/read_write.c:593
ksys_write+0x1ee/0x250 fs/read_write.c:648
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> (&client->buffer_lock){....}-{2:2} {
INITIAL USE at:
lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:354 [inline]
evdev_pass_values+0x195/0xa70 drivers/input/evdev.c:262
evdev_events+0x20c/0x330 drivers/input/evdev.c:307
input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
input_pass_values drivers/input/input.c:134 [inline]
input_handle_event+0x324/0x1400 drivers/input/input.c:399
input_inject_event+0x2f5/0x310 drivers/input/input.c:471
evdev_write+0x424/0x750 drivers/input/evdev.c:530
vfs_write+0x28e/0x700 fs/read_write.c:593
ksys_write+0x1ee/0x250 fs/read_write.c:648
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
}
... key at: [<ffffffff8e5f4360>] __key.4+0x0/0x40
... acquired at:
__raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
_raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
kill_fasync_rcu fs/fcntl.c:1002 [inline]
kill_fasync fs/fcntl.c:1023 [inline]
kill_fasync+0x14b/0x460 fs/fcntl.c:1016
__pass_event drivers/input/evdev.c:240 [inline]
evdev_pass_values+0x72a/0xa70 drivers/input/evdev.c:279
evdev_events+0x20c/0x330 drivers/input/evdev.c:307
input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
input_pass_values drivers/input/input.c:134 [inline]
input_handle_event+0x324/0x1400 drivers/input/input.c:399
input_inject_event+0x2f5/0x310 drivers/input/input.c:471
evdev_write+0x424/0x750 drivers/input/evdev.c:530
vfs_write+0x28e/0x700 fs/read_write.c:593
ksys_write+0x1ee/0x250 fs/read_write.c:648
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> (&new->fa_lock){....}-{2:2} {
INITIAL USE at:
lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398
__raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
_raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
kill_fasync_rcu fs/fcntl.c:1002 [inline]
kill_fasync fs/fcntl.c:1023 [inline]
kill_fasync+0x14b/0x460 fs/fcntl.c:1016
__pass_event drivers/input/evdev.c:240 [inline]
evdev_pass_values+0x72a/0xa70 drivers/input/evdev.c:279
evdev_events+0x20c/0x330 drivers/input/evdev.c:307
input_to_handler+0x2a0/0x4c0 drivers/input/input.c:115
input_pass_values.part.0+0x284/0x700 drivers/input/input.c:145
input_pass_values drivers/input/input.c:134 [inline]
input_handle_event+0x324/0x1400 drivers/input/input.c:399
input_inject_event+0x2f5/0x310 drivers/input/input.c:471
evdev_write+0x424/0x750 drivers/input/evdev.c:530
vfs_write+0x28e/0x700 fs/read_write.c:593
ksys_write+0x1ee/0x250 fs/read_write.c:648
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
(null) at:
================================================================================
UBSAN: array-index-out-of-bounds in kernel/locking/lockdep.c:2240:40
index 9 is out of range for type 'lock_trace *[9]'
CPU: 1 PID: 9635 Comm: syz-executor.4 Not tainted 5.9.0-rc6-next-20200924-syzkaller #0
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+0x198/0x1fb lib/dump_stack.c:118
ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
__ubsan_handle_out_of_bounds.cold+0x62/0x6c lib/ubsan.c:356
print_lock_class_header kernel/locking/lockdep.c:2240 [inline]
print_shortest_lock_dependencies.cold+0x11c/0x2e2 kernel/locking/lockdep.c:2263
print_irq_inversion_bug.part.0+0x2c6/0x2ee kernel/locking/lockdep.c:3769
print_irq_inversion_bug kernel/locking/lockdep.c:3694 [inline]
check_usage_backwards kernel/locking/lockdep.c:3838 [inline]
mark_lock_irq kernel/locking/lockdep.c:3928 [inline]
mark_lock.cold+0x1a/0x74 kernel/locking/lockdep.c:4375
mark_usage kernel/locking/lockdep.c:4266 [inline]
__lock_acquire+0x11ef/0x56d0 kernel/locking/lockdep.c:4750
lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398
__raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
_raw_read_lock+0x5b/0x70 kernel/locking/spinlock.c:223
f_getown_ex fs/fcntl.c:206 [inline]
do_fcntl+0x8f6/0x10c0 fs/fcntl.c:387
__do_sys_fcntl fs/fcntl.c:463 [inline]
__se_sys_fcntl fs/fcntl.c:448 [inline]
__x64_sys_fcntl+0x165/0x1e0 fs/fcntl.c:448
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e179
Code: 3d b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 0b b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffb745dac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000048
RAX: ffffffffffffffda RBX: 00000000000032c0 RCX: 000000000045e179
RDX: 0000000020000000 RSI: 0000000000000010 RDI: 0000000000000003
RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007fffc8ae79bf R14: 00007ffb745db9c0 R15: 000000000118cf4c
================================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

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