[v5.15] possible deadlock in console_lock_spinning_enable

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 115472395b0a Linux 5.15.104
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16928b1ec80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e597b110d58e7b4
dashboard link: https://syzkaller.appspot.com/bug?extid=4dfdb5af93b862bd0e21
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/76798ca1c9b6/disk-11547239.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3b608633c8f5/vmlinux-11547239.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8836fafb618b/Image-11547239.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4dfdb5...@syzkaller.appspotmail.com

FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
5.15.104-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.1/26852 is trying to acquire lock:
ffff800014a87a00 (console_owner){-...}-{0:0}, at: console_lock_spinning_enable+0x38/0x78 kernel/printk/printk.c:1802

but task is already holding lock:
ffff0000d9fbf958 (&port->lock){....}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x48/0x324 drivers/tty/tty_buffer.c:585

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&port->lock){....}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xc4/0x14c kernel/locking/spinlock.c:162
tty_port_tty_get+0x2c/0x124 drivers/tty/tty_port.c:289
tty_port_default_wakeup+0x20/0x54 drivers/tty/tty_port.c:48
tty_port_tty_wakeup+0x64/0x78 drivers/tty/tty_port.c:389
uart_write_wakeup+0x4c/0x64 drivers/tty/serial/serial_core.c:111
pl011_tx_chars+0xd04/0x157c drivers/tty/serial/amba-pl011.c:1505
pl011_start_tx_pio drivers/tty/serial/amba-pl011.c:1351 [inline]
pl011_start_tx+0x364/0x8b8 drivers/tty/serial/amba-pl011.c:1363
__uart_start drivers/tty/serial/serial_core.c:132 [inline]
uart_write+0x62c/0x8b8 drivers/tty/serial/serial_core.c:589
process_output_block drivers/tty/n_tty.c:592 [inline]
n_tty_write+0xae0/0xf38 drivers/tty/n_tty.c:2322
do_tty_write drivers/tty/tty_io.c:1038 [inline]
file_tty_write+0x44c/0x758 drivers/tty/tty_io.c:1110
tty_write drivers/tty/tty_io.c:1131 [inline]
redirected_tty_write+0xc4/0x10c drivers/tty/tty_io.c:1154
call_write_iter include/linux/fs.h:2103 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x87c/0xb3c fs/read_write.c:594
ksys_write+0x15c/0x26c fs/read_write.c:647
__do_sys_write fs/read_write.c:659 [inline]
__se_sys_write fs/read_write.c:656 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:656
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #1 (&port_lock_key){-...}-{2:2}:
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0xb0/0x10c kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:363 [inline]
pl011_console_write+0x1a0/0x774 drivers/tty/serial/amba-pl011.c:2354
call_console_drivers kernel/printk/printk.c:1953 [inline]
console_unlock+0xbac/0x1394 kernel/printk/printk.c:2734
register_console+0x560/0x870 kernel/printk/printk.c:3064
uart_configure_port drivers/tty/serial/serial_core.c:2443 [inline]
uart_add_one_port+0xe70/0x1540 drivers/tty/serial/serial_core.c:2958
pl011_register_port+0x1a0/0x434 drivers/tty/serial/amba-pl011.c:2799
sbsa_uart_probe+0x474/0x5dc drivers/tty/serial/amba-pl011.c:2934
platform_probe+0x148/0x1c0 drivers/base/platform.c:1411
really_probe+0x26c/0xaec drivers/base/dd.c:595
__driver_probe_device+0x1bc/0x3f8 drivers/base/dd.c:750
driver_probe_device+0x78/0x34c drivers/base/dd.c:780
__device_attach_driver+0x28c/0x4d8 drivers/base/dd.c:902
bus_for_each_drv+0x158/0x1e0 drivers/base/bus.c:427
__device_attach+0x2f0/0x480 drivers/base/dd.c:974
device_initial_probe+0x24/0x34 drivers/base/dd.c:1023
bus_probe_device+0xbc/0x1c8 drivers/base/bus.c:487
device_add+0xae0/0xef4 drivers/base/core.c:3394
platform_device_add+0x3f8/0x708 drivers/base/platform.c:712
platform_device_register_full+0x508/0x618 drivers/base/platform.c:835
acpi_create_platform_device+0x4d8/0x650 drivers/acpi/acpi_platform.c:154
acpi_default_enumeration+0x6c/0xdc drivers/acpi/scan.c:2087
acpi_bus_attach+0x88c/0xab4 drivers/acpi/scan.c:2197
acpi_bus_attach+0x314/0xab4 drivers/acpi/scan.c:2203
acpi_bus_attach+0x314/0xab4 drivers/acpi/scan.c:2203
acpi_bus_scan+0xe4/0x20c drivers/acpi/scan.c:2375
acpi_scan_init+0x220/0x71c drivers/acpi/scan.c:2550
acpi_init+0x188/0x24c drivers/acpi/bus.c:1346
do_one_initcall+0x234/0x990 init/main.c:1306
do_initcall_level+0x154/0x214 init/main.c:1379
do_initcalls+0x58/0xac init/main.c:1395
do_basic_setup+0x8c/0xa0 init/main.c:1414
kernel_init_freeable+0x470/0x650 init/main.c:1619
kernel_init+0x24/0x294 init/main.c:1510
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

-> #0 (console_owner){-...}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3787 [inline]
__lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
console_lock_spinning_enable+0x68/0x78 kernel/printk/printk.c:1805
console_unlock+0x910/0x1394 kernel/printk/printk.c:2731
vprintk_emit+0x13c/0x218 kernel/printk/printk.c:2268
vprintk_default+0xa0/0xe4 kernel/printk/printk.c:2279
vprintk+0x218/0x2f0 kernel/printk/printk_safe.c:50
_printk+0xdc/0x128 kernel/printk/printk.c:2289
fail_dump lib/fault-inject.c:45 [inline]
should_fail+0x3e0/0x5cc lib/fault-inject.c:146
__should_failslab+0xbc/0x110 mm/failslab.c:33
should_failslab+0x10/0x28 mm/slab_common.c:1337
slab_pre_alloc_hook+0x64/0xe8 mm/slab.h:494
slab_alloc_node mm/slub.c:3134 [inline]
slab_alloc mm/slub.c:3228 [inline]
__kmalloc+0xc0/0x4c8 mm/slub.c:4403
kmalloc include/linux/slab.h:596 [inline]
tty_buffer_alloc drivers/tty/tty_buffer.c:177 [inline]
__tty_buffer_request_room+0x1a4/0x440 drivers/tty/tty_buffer.c:276
tty_insert_flip_string_fixed_flag drivers/tty/tty_buffer.c:322 [inline]
tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
tty_insert_flip_string_and_push_buffer+0x74/0x324 drivers/tty/tty_buffer.c:586
pty_write+0xb8/0xe8 drivers/tty/pty.c:118
tty_put_char+0x110/0x170 drivers/tty/tty_io.c:3176
__process_echoes+0x3f8/0xd54 drivers/tty/n_tty.c:725
flush_echoes drivers/tty/n_tty.c:826 [inline]
__receive_buf drivers/tty/n_tty.c:1579 [inline]
n_tty_receive_buf_common+0x591c/0x5dc0 drivers/tty/n_tty.c:1674
n_tty_receive_buf+0x40/0x54 drivers/tty/n_tty.c:1703
tiocsti+0x284/0x35c drivers/tty/tty_io.c:2312
tty_ioctl+0x354/0xdf4 drivers/tty/tty_io.c:2721
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

Chain exists of:
console_owner --> &port_lock_key --> &port->lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&port->lock);
lock(&port_lock_key);
lock(&port->lock);
lock(console_owner);

*** DEADLOCK ***

6 locks held by syz-executor.1/26852:
#0: ffff0000d7c80098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
#1: ffff0000d9fbc8b8 (&port->buf.lock/1){+.+.}-{3:3}, at: tty_buffer_lock_exclusive+0x48/0x84 drivers/tty/tty_buffer.c:61
#2: ffff0000d7c802e8 (&o_tty->termios_rwsem/1){++++}-{3:3}, at: n_tty_receive_buf_common+0x78/0x5dc0 drivers/tty/n_tty.c:1637
#3: ffff8000189e2378 (&ldata->output_lock){+.+.}-{3:3}, at: flush_echoes drivers/tty/n_tty.c:824 [inline]
#3: ffff8000189e2378 (&ldata->output_lock){+.+.}-{3:3}, at: __receive_buf drivers/tty/n_tty.c:1579 [inline]
#3: ffff8000189e2378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_receive_buf_common+0x58e8/0x5dc0 drivers/tty/n_tty.c:1674
#4: ffff0000d9fbf958 (&port->lock){....}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x48/0x324 drivers/tty/tty_buffer.c:585
#5: ffff80001496f500 (console_lock){+.+.}-{0:0}, at: console_trylock_spinning+0x1c/0x280 kernel/printk/printk.c:1867

stack backtrace:
CPU: 1 PID: 26852 Comm: syz-executor.1 Not tainted 5.15.104-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call trace:
dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
dump_stack+0x1c/0x58 lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3787 [inline]
__lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
console_lock_spinning_enable+0x68/0x78 kernel/printk/printk.c:1805
console_unlock+0x910/0x1394 kernel/printk/printk.c:2731
vprintk_emit+0x13c/0x218 kernel/printk/printk.c:2268
vprintk_default+0xa0/0xe4 kernel/printk/printk.c:2279
vprintk+0x218/0x2f0 kernel/printk/printk_safe.c:50
_printk+0xdc/0x128 kernel/printk/printk.c:2289
fail_dump lib/fault-inject.c:45 [inline]
should_fail+0x3e0/0x5cc lib/fault-inject.c:146
__should_failslab+0xbc/0x110 mm/failslab.c:33
should_failslab+0x10/0x28 mm/slab_common.c:1337
slab_pre_alloc_hook+0x64/0xe8 mm/slab.h:494
slab_alloc_node mm/slub.c:3134 [inline]
slab_alloc mm/slub.c:3228 [inline]
__kmalloc+0xc0/0x4c8 mm/slub.c:4403
kmalloc include/linux/slab.h:596 [inline]
tty_buffer_alloc drivers/tty/tty_buffer.c:177 [inline]
__tty_buffer_request_room+0x1a4/0x440 drivers/tty/tty_buffer.c:276
tty_insert_flip_string_fixed_flag drivers/tty/tty_buffer.c:322 [inline]
tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
tty_insert_flip_string_and_push_buffer+0x74/0x324 drivers/tty/tty_buffer.c:586
pty_write+0xb8/0xe8 drivers/tty/pty.c:118
tty_put_char+0x110/0x170 drivers/tty/tty_io.c:3176
__process_echoes+0x3f8/0xd54 drivers/tty/n_tty.c:725
flush_echoes drivers/tty/n_tty.c:826 [inline]
__receive_buf drivers/tty/n_tty.c:1579 [inline]
n_tty_receive_buf_common+0x591c/0x5dc0 drivers/tty/n_tty.c:1674
n_tty_receive_buf+0x40/0x54 drivers/tty/n_tty.c:1703
tiocsti+0x284/0x35c drivers/tty/tty_io.c:2312
tty_ioctl+0x354/0xdf4 drivers/tty/tty_io.c:2721
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
CPU: 1 PID: 26852 Comm: syz-executor.1 Not tainted 5.15.104-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call trace:
dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
dump_stack+0x1c/0x58 lib/dump_stack.c:113
fail_dump lib/fault-inject.c:52 [inline]
should_fail+0x400/0x5cc lib/fault-inject.c:146
__should_failslab+0xbc/0x110 mm/failslab.c:33
should_failslab+0x10/0x28 mm/slab_common.c:1337
slab_pre_alloc_hook+0x64/0xe8 mm/slab.h:494
slab_alloc_node mm/slub.c:3134 [inline]
slab_alloc mm/slub.c:3228 [inline]
__kmalloc+0xc0/0x4c8 mm/slub.c:4403
kmalloc include/linux/slab.h:596 [inline]
tty_buffer_alloc drivers/tty/tty_buffer.c:177 [inline]
__tty_buffer_request_room+0x1a4/0x440 drivers/tty/tty_buffer.c:276
tty_insert_flip_string_fixed_flag drivers/tty/tty_buffer.c:322 [inline]
tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
tty_insert_flip_string_and_push_buffer+0x74/0x324 drivers/tty/tty_buffer.c:586
pty_write+0xb8/0xe8 drivers/tty/pty.c:118
tty_put_char+0x110/0x170 drivers/tty/tty_io.c:3176
__process_echoes+0x3f8/0xd54 drivers/tty/n_tty.c:725
flush_echoes drivers/tty/n_tty.c:826 [inline]
__receive_buf drivers/tty/n_tty.c:1579 [inline]
n_tty_receive_buf_common+0x591c/0x5dc0 drivers/tty/n_tty.c:1674
n_tty_receive_buf+0x40/0x54 drivers/tty/n_tty.c:1703
tiocsti+0x284/0x35c drivers/tty/tty_io.c:2312
tty_ioctl+0x354/0xdf4 drivers/tty/tty_io.c:2721
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584


---
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 syzk...@googlegroups.com.

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

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 115472395b0a Linux 5.15.104
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=14bf8bcec80000

kernel config: https://syzkaller.appspot.com/x/.config?x=e597b110d58e7b4
dashboard link: https://syzkaller.appspot.com/bug?extid=4dfdb5af93b862bd0e21
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15107471c80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13f5ccdec80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/76798ca1c9b6/disk-11547239.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3b608633c8f5/vmlinux-11547239.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8836fafb618b/Image-11547239.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4dfdb5...@syzkaller.appspotmail.com

FAULT_INJECTION: forcing a failure.

name failslab, interval 1, probability 0, space 0, times 1

======================================================
WARNING: possible circular locking dependency detected
5.15.104-syzkaller #0 Not tainted
------------------------------------------------------

syz-executor247/4057 is trying to acquire lock:
ffff800014a87a00 (console_owner){....}-{0:0}, at: console_lock_spinning_enable+0x38/0x78 kernel/printk/printk.c:1802

but task is already holding lock:

ffff0000ce7b6158 (&port->lock){....}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x48/0x324 drivers/tty/tty_buffer.c:585

-> #1 (&port_lock_key){....}-{2:2}:

-> #0 (console_owner){....}-{0:0}:

6 locks held by syz-executor247/4057:
#0: ffff0000d84cd098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
#1: ffff0000ce7b58b8 (&port->buf.lock/1){+.+.}-{3:3}, at: tty_buffer_lock_exclusive+0x48/0x84 drivers/tty/tty_buffer.c:61
#2: ffff0000d84cd2e8 (&o_tty->termios_rwsem/1){++++}-{3:3}, at: n_tty_receive_buf_common+0x78/0x5dc0 drivers/tty/n_tty.c:1637
#3: ffff800018db0378 (&ldata->output_lock){+.+.}-{3:3}, at: flush_echoes drivers/tty/n_tty.c:824 [inline]
#3: ffff800018db0378 (&ldata->output_lock){+.+.}-{3:3}, at: __receive_buf drivers/tty/n_tty.c:1579 [inline]
#3: ffff800018db0378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_receive_buf_common+0x58e8/0x5dc0 drivers/tty/n_tty.c:1674
#4: ffff0000ce7b6158 (&port->lock){....}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x48/0x324 drivers/tty/tty_buffer.c:585

#5: ffff80001496f500 (console_lock){+.+.}-{0:0}, at: console_trylock_spinning+0x1c/0x280 kernel/printk/printk.c:1867

stack backtrace:

CPU: 1 PID: 4057 Comm: syz-executor247 Not tainted 5.15.104-syzkaller #0

CPU: 1 PID: 4057 Comm: syz-executor247 Not tainted 5.15.104-syzkaller #0

[syzbot]

syzbot suspects this issue could be fixed by backporting the following commit:

commit 09c5ba0aa2fcfdadb17d045c3ee6f86d69270df7
git tree: upstream
Author: John Ogness <john....@linutronix.de>
Date: Thu Apr 21 21:22:48 2022 +0000

printk: add kthread console printers

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1133cf11e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ffd22c928742e176
dashboard link: https://syzkaller.appspot.com/bug?extid=4dfdb5af93b862bd0e21
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16edcb71e80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14ba69c6e80000


Please keep in mind that other backports might be required as well.

For information about bisection process see: https://goo.gl/tpsmEJ#bisection