INFO: task syz.8.211:7789 blocked for more than 143 seconds.
Not tainted 6.15.0-rc5-syzkaller-00353-gcd802e7e5f1e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.211 state:D stack:24408 pid:7789 tgid:7788 ppid:7272 task_flags:0x400140 flags:0x00000004
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x168f/0x4c70 kernel/sched/core.c:6767
__schedule_loop kernel/sched/core.c:6845 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6860
percpu_rwsem_wait+0x2ab/0x300 kernel/locking/percpu-rwsem.c:162
__percpu_down_read+0xe3/0x120 kernel/locking/percpu-rwsem.c:177
percpu_down_read include/linux/percpu-rwsem.h:66 [inline]
__sb_start_write include/linux/fs.h:1783 [inline]
sb_start_write+0x185/0x1c0 include/linux/fs.h:1919
mnt_want_write+0x41/0x90 fs/namespace.c:556
open_last_lookups fs/namei.c:3789 [inline]
path_openat+0x85d/0x3830 fs/namei.c:4036
do_filp_open+0x1fa/0x410 fs/namei.c:4066
do_sys_openat2+0x121/0x1c0 fs/open.c:1429
do_sys_open fs/open.c:1444 [inline]
__do_sys_open fs/open.c:1452 [inline]
__se_sys_open fs/open.c:1448 [inline]
__x64_sys_open+0x11e/0x150 fs/open.c:1448
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcfd0f8e969
RSP: 002b:00007fcfd1e97038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007fcfd11b5fa0 RCX: 00007fcfd0f8e969
RDX: 0000000000000000 RSI: 000000000014927e RDI: 0000200000000180
RBP: 00007fcfd1010ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fcfd11b5fa0 R15: 00007ffcd9858468
INFO: task syz.8.211:7830 blocked for more than 144 seconds.
Not tainted 6.15.0-rc5-syzkaller-00353-gcd802e7e5f1e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.211 state:D stack:28952 pid:7830 tgid:7788 ppid:7272 task_flags:0x400040 flags:0x00000004
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x168f/0x4c70 kernel/sched/core.c:6767
__schedule_loop kernel/sched/core.c:6845 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6860
percpu_rwsem_wait+0x2ab/0x300 kernel/locking/percpu-rwsem.c:162
__percpu_down_read+0xe3/0x120 kernel/locking/percpu-rwsem.c:177
percpu_down_read include/linux/percpu-rwsem.h:66 [inline]
__sb_start_write include/linux/fs.h:1783 [inline]
sb_start_write+0x185/0x1c0 include/linux/fs.h:1919
mnt_want_write+0x41/0x90 fs/namespace.c:556
open_last_lookups fs/namei.c:3789 [inline]
path_openat+0x85d/0x3830 fs/namei.c:4036
do_filp_open+0x1fa/0x410 fs/namei.c:4066
do_sys_openat2+0x121/0x1c0 fs/open.c:1429
do_sys_open fs/open.c:1444 [inline]
__do_sys_creat fs/open.c:1522 [inline]
__se_sys_creat fs/open.c:1516 [inline]
__x64_sys_creat+0x8f/0xc0 fs/open.c:1516
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcfd0f8e969
RSP: 002b:00007fcfd1e55038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fcfd11b6160 RCX: 00007fcfd0f8e969
RDX: 0000000000000000 RSI: 00000000000001b0 RDI: 0000200000000600
RBP: 00007fcfd1010ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fcfd11b6160 R15: 00007ffcd9858468
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8df3d860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8df3d860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8df3d860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
2 locks held by getty/5580:
#0: ffff888034ce20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90002ffe2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by syz-executor/5822:
#0: ffffffff8f2e4a48 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline]
#0: ffffffff8f2e4a48 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3390
#1: ffffffff8df43338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline]
#1: ffffffff8df43338 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f4/0x730 kernel/rcu/tree_exp.h:998
1 lock held by udevd/5878:
1 lock held by syz.8.211/7789:
#0: ffff88802d5e4420 (sb_writers#28){++++}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556
1 lock held by syz.8.211/7830:
#0: ffff88802d5e4420 (sb_writers#28){++++}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:556
1 lock held by rm/10404:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc5-syzkaller-00353-gcd802e7e5f1e #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
watchdog+0xfee/0x1030 kernel/hung_task.c:437
kthread+0x70e/0x8a0 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 10304 Comm: syz.7.442 Not tainted 6.15.0-rc5-syzkaller-00353-gcd802e7e5f1e #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:409
Code: e8 ce 22 89 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 bf f1 e8 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc9000410f390 EFLAGS: 00000002
RAX: 1ffffffff3363900 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffffff99b1cc50 R08: ffff8880242f0237 R09: 1ffff1100485e046
R10: dffffc0000000000 R11: ffffffff8536ab60 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99b1c9c0 R15: 0000000000000000
FS: 00007fd91f1a76c0(0000) GS:ffff8881261fb000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc25429e000 CR3: 000000003ae60000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:137 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline]
wait_for_lsr+0x19e/0x2f0 drivers/tty/serial/8250/8250_port.c:2098
fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3348 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3371 [inline]
serial8250_console_write+0x134c/0x1ba0 drivers/tty/serial/8250/8250_port.c:3456
console_emit_next_record kernel/printk/printk.c:3138 [inline]
console_flush_all+0x725/0xc40 kernel/printk/printk.c:3226
__console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
console_unlock+0xc4/0x270 kernel/printk/printk.c:3325
vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450
bch2_print_maybe_redirect fs/bcachefs/super.c:110 [inline]
__bch2_print+0x176/0x220 fs/bcachefs/super.c:129
bch2_fs_free+0x37e/0x400 fs/bcachefs/super.c:679
bch2_fs_get_tree+0xb0c/0x13b0 fs/bcachefs/fs.c:2606
vfs_get_tree+0x8f/0x2b0 fs/super.c:1759
do_new_mount+0x24a/0xa40 fs/namespace.c:3881
do_mount fs/namespace.c:4221 [inline]
__do_sys_mount fs/namespace.c:4432 [inline]
__se_sys_mount+0x317/0x410 fs/namespace.c:4409
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd91e39010a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd91f1a6e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fd91f1a6ef0 RCX: 00007fd91e39010a
RDX: 0000200000000040 RSI: 0000200000000000 RDI: 00007fd91f1a6eb0
RBP: 0000200000000040 R08: 00007fd91f1a6ef0 R09: 0000000000010000
R10: 0000000000010000 R11: 0000000000000246 R12: 0000200000000000
R13: 00007fd91f1a6eb0 R14: 00000000000058d3 R15: 0000200000000080