possible deadlock in kill_fasync

From: syzbot
Date: Sat Oct 03 2020 - 06:29:37 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 663b07a4 Add linux-next specific files for 20200928
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16202587900000
kernel config: https://syzkaller.appspot.com/x/.config?x=4279ffe1791babf
dashboard link: https://syzkaller.appspot.com/bug?extid=3e12e14ee01b675e1af2
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+3e12e14ee01b675e1af2@xxxxxxxxxxxxxxxxxxxxxxxxx

========================================================
WARNING: possible irq lock inversion dependency detected
5.9.0-rc7-next-20200928-syzkaller #0 Not tainted
--------------------------------------------------------
kworker/u4:3/37 just changed the state of lock:
ffff88809f2f6f30 (&new->fa_lock){.+..}-{2:2}, at: kill_fasync_rcu fs/fcntl.c:1002 [inline]
ffff88809f2f6f30 (&new->fa_lock){.+..}-{2:2}, at: kill_fasync fs/fcntl.c:1023 [inline]
ffff88809f2f6f30 (&new->fa_lock){.+..}-{2:2}, at: kill_fasync+0x14b/0x460 fs/fcntl.c:1016
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 --> &client->buffer_lock --> &new->fa_lock

Possible interrupt unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&new->fa_lock);
local_irq_disable();
lock(&dev->event_lock);
lock(&client->buffer_lock);
<Interrupt>
lock(&dev->event_lock);

*** DEADLOCK ***

7 locks held by kworker/u4:3/37:
#0: ffff888099228138 ((wq_completion)bat_events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888099228138 ((wq_completion)bat_events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
#0: ffff888099228138 ((wq_completion)bat_events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: ffff888099228138 ((wq_completion)bat_events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
#0: ffff888099228138 ((wq_completion)bat_events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: ffff888099228138 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 kernel/workqueue.c:2240
#1: ffffc90000eb7da8 ((work_completion)(&(&forw_packet_aggr->delayed_work)->work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2244
#2: ffffffff8a553ca0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1d7/0x2d30 net/core/dev.c:4072
#3: ffffffff8a553d00 (rcu_read_lock){....}-{1:2}, at: dev_queue_xmit_nit+0x0/0xac0 net/core/dev.c:5620
#4: ffffffff8a553d00 (rcu_read_lock){....}-{1:2}, at: sock_def_readable+0x0/0x4c0 include/net/sock.h:1804
#5: ffffffff8a553d00 (rcu_read_lock){....}-{1:2}, at: rcu_lock_release include/linux/rcupdate.h:258 [inline]
#5: ffffffff8a553d00 (rcu_read_lock){....}-{1:2}, at: rcu_read_unlock include/linux/rcupdate.h:696 [inline]
#5: ffffffff8a553d00 (rcu_read_lock){....}-{1:2}, at: sock_def_readable+0x1c7/0x4c0 net/core/sock.c:2897
#6: ffffffff8a553d00 (rcu_read_lock){....}-{1:2}, at: kill_fasync+0x3d/0x460 fs/fcntl.c:1021

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_irq_on_stack+0xf/0x20
__run_irq_on_irqstack arch/x86/include/asm/irq_stack.h:48 [inline]
run_irq_on_irqstack_cond arch/x86/include/asm/irq_stack.h:101 [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
arch_local_irq_restore arch/x86/include/asm/paravirt.h:653 [inline]
console_unlock+0xa31/0xd20 kernel/printk/printk.c:2500
vprintk_emit+0x2a6/0x6e0 kernel/printk/printk.c:2021
vprintk_func+0x8d/0x1e0 kernel/printk/printk_safe.c:393
printk+0xba/0xed kernel/printk/printk.c:2069
vivid_create_devnodes drivers/media/test-drivers/vivid/vivid-core.c:1528 [inline]
vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:1886 [inline]
vivid_probe.cold+0x7178/0x845c drivers/media/test-drivers/vivid/vivid-core.c:1941
platform_drv_probe+0x87/0x140 drivers/base/platform.c:761
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
bus_add_driver+0x348/0x5a0 drivers/base/bus.c:622
driver_register+0x220/0x3a0 drivers/base/driver.c:171
vivid_init+0x37/0x64 drivers/media/test-drivers/vivid/vivid-core.c:2069
do_one_initcall+0x103/0x6f0 init/main.c:1205
do_initcall_level init/main.c:1278 [inline]
do_initcalls init/main.c:1294 [inline]
do_basic_setup init/main.c:1314 [inline]
kernel_init_freeable+0x652/0x6d6 init/main.c:1514
kernel_init+0xd/0x1b8 init/main.c:1403
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
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+0x552/0x6e0 drivers/leds/led-class.c:417
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: [<ffffffff8e607fa0>] __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: [<ffffffff8e6084a0>] __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} {
HARDIRQ-ON-R at:
lock_acquire+0x1f2/0xaa0 kernel/locking/lockdep.c:5398
__raw_read_lock include/linux/rwlock_api_smp.h:149 [inline]
_raw_read_lock+0x36/0x70 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
sock_wake_async+0xd2/0x160 net/socket.c:1331
sk_wake_async include/net/sock.h:2259 [inline]
sk_wake_async include/net/sock.h:2255 [inline]
sock_def_readable+0x2cb/0x4c0 net/core/sock.c:2896
__sock_queue_rcv_skb+0x520/0xaa0 net/core/sock.c:468
sock_queue_rcv_skb+0x41/0x60 net/core/sock.c:481
packet_rcv_spkt+0x3ad/0x530 net/packet/af_packet.c:1856
dev_queue_xmit_nit+0x7f6/0xac0 net/core/dev.c:2362
xmit_one net/core/dev.c:3558 [inline]
dev_hard_start_xmit+0xa4/0x880 net/core/dev.c:3578
__dev_queue_xmit+0x2062/0x2d30 net/core/dev.c:4137
batadv_send_skb_packet+0x4a9/0x5f0 net/batman-adv/send.c:108
batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:394 [inline]
batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:420 [inline]
batadv_iv_send_outstanding_bat_ogm_packet+0x6ad/0x800 net/batman-adv/bat_iv_ogm.c:1712
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
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: 0 PID: 37 Comm: kworker/u4:3 Not tainted 5.9.0-rc7-next-20200928-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
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+0x36/0x70 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
sock_wake_async+0xd2/0x160 net/socket.c:1331
sk_wake_async include/net/sock.h:2259 [inline]
sk_wake_async include/net/sock.h:2255 [inline]
sock_def_readable+0x2cb/0x4c0 net/core/sock.c:2896
__sock_queue_rcv_skb+0x520/0xaa0 net/core/sock.c:468
sock_queue_rcv_skb+0x41/0x60 net/core/sock.c:481
packet_rcv_spkt+0x3ad/0x530 net/packet/af_packet.c:1856
dev_queue_xmit_nit+0x7f6/0xac0 net/core/dev.c:2362
xmit_one net/core/dev.c:3558 [inline]
dev_hard_start_xmit+0xa4/0x880 net/core/dev.c:3578
__dev_queue_xmit+0x2062/0x2d30 net/core/dev.c:4137
batadv_send_skb_packet+0x4a9/0x5f0 net/batman-adv/send.c:108
batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:394 [inline]
batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:420 [inline]
batadv_iv_send_outstanding_bat_ogm_packet+0x6ad/0x800 net/batman-adv/bat_iv_ogm.c:1712
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
================================================================================

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