syzbot

INFO: task syz-executor.2:5992 blocked for more than 143 seconds.
      Not tainted 6.9.0-rc7-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:27352 pid:5992  tgid:5983  ppid:5566   flags:0x00000006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5409 [inline]
 __schedule+0x1796/0x4a00 kernel/sched/core.c:6746
 __schedule_loop kernel/sched/core.c:6823 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6838
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6895
 rwsem_down_write_slowpath+0xeeb/0x13b0 kernel/locking/rwsem.c:1178
 __down_write_common+0x1af/0x200 kernel/locking/rwsem.c:1306
 inode_lock include/linux/fs.h:795 [inline]
 open_last_lookups fs/namei.c:3563 [inline]
 path_openat+0x7d3/0x3240 fs/namei.c:3796
 do_filp_open+0x235/0x490 fs/namei.c:3826
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1406
 do_sys_open fs/open.c:1421 [inline]
 __do_sys_creat fs/open.c:1497 [inline]
 __se_sys_creat fs/open.c:1491 [inline]
 __x64_sys_creat+0x123/0x170 fs/open.c:1491
 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
RIP: 0033:0x7f884867dca9
RSP: 002b:00007f88481de0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f88487ac050 RCX: 00007f884867dca9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000140
RBP: 00007f88486c947e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f88487ac050 R15: 00007fff61d87178
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
3 locks held by kworker/u8:10/2849:
2 locks held by getty/4831:
 #0: ffff88802b18e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002f0e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201
3 locks held by kworker/0:5/5142:
 #0: ffff888015080948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3242 [inline]
 #0: ffff888015080948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x17c0 kernel/workqueue.c:3348
 #1: ffffc90003837d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3243 [inline]
 #1: ffffc90003837d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x17c0 kernel/workqueue.c:3348
 #2: ffff88805e937240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x2d1/0x4130 drivers/net/netdevsim/fib.c:1489
1 lock held by syz-executor.2/5984:
2 locks held by syz-executor.2/5992:
 #0: ffff88802c614420 (sb_writers#30){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:409
 #1: ffff888056b48188 (&type->i_mutex_dir_key#21){++++}-{3:3}, at: inode_lock include/linux/fs.h:795 [inline]
 #1: ffff888056b48188 (&type->i_mutex_dir_key#21){++++}-{3:3}, at: open_last_lookups fs/namei.c:3563 [inline]
 #1: ffff888056b48188 (&type->i_mutex_dir_key#21){++++}-{3:3}, at: path_openat+0x7d3/0x3240 fs/namei.c:3796
4 locks held by syz-executor.2/7027:
 #0: ffff88801dc08420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:409
 #1: ffff888042288400 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:830 [inline]
 #1: ffff888042288400 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_unlinkat+0x26a/0x830 fs/namei.c:4386
 #2: ffff88805f0cca00 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: inode_lock include/linux/fs.h:795 [inline]
 #2: ffff88805f0cca00 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: vfs_unlink+0xe4/0x600 fs/namei.c:4324
 #3: ffff8880b953e658 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559
3 locks held by syz-executor.3/7475:
2 locks held by syz-executor.1/7603:
 #0: ffff88801dc08420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:409
 #1: ffff888052da4a00 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:830 [inline]
 #1: ffff888052da4a00 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: do_unlinkat+0x26a/0x830 fs/namei.c:4386
3 locks held by syz-executor.0/7917:

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.9.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xfde/0x1020 kernel/hung_task.c:380
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7917 Comm: syz-executor.0 Not tainted 6.9.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:io_serial_in+0x65/0xb0 drivers/tty/serial/8250/8250_port.c:406
Code: 20 00 00 00 89 ee e8 3a 7d 62 fc 83 fd 1f 77 4c e8 30 7a 62 fc 89 e9 41 d3 e6 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 38 00 <74> 08 48 89 df e8 41 d5 c3 fc 44 03 33 44 89 f2 ec 0f b6 c0 5b 41
RSP: 0018:ffffc900046f63f8 EFLAGS: 00000046
RAX: 1ffffffff29446ec RBX: ffffffff94a23760 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 0000000000000000 R08: ffffffff85338d56 R09: 1ffff11003fa4046
R10: dffffc0000000000 R11: ffffffff85338d10 R12: dffffc0000000000
R13: 00000000000026d4 R14: 0000000000000005 R15: dffffc0000000000
FS:  000055556ba85480(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd0ff69c440 CR3: 000000002db76000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:117 [inline]
 serial_lsr_in drivers/tty/serial/8250/8250.h:139 [inline]
 wait_for_lsr drivers/tty/serial/8250/8250_port.c:2071 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3318 [inline]
 serial8250_console_write+0x1099/0x1770 drivers/tty/serial/8250/8250_port.c:3396
 console_emit_next_record kernel/printk/printk.c:2913 [inline]
 console_flush_all+0x865/0xfd0 kernel/printk/printk.c:2979
 console_unlock+0x13b/0x4d0 kernel/printk/printk.c:3048
 vprintk_emit+0x5a6/0x770 kernel/printk/printk.c:2348
 _printk+0xd5/0x120 kernel/printk/printk.c:2373
 batadv_check_known_mac_addr+0x2bd/0x410 net/batman-adv/hard-interface.c:528
 batadv_hard_if_event+0x3a5/0x1620 net/batman-adv/hard-interface.c:998
 notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:1988 [inline]
 call_netdevice_notifiers net/core/dev.c:2002 [inline]
 dev_set_mac_address+0x3d9/0x510 net/core/dev.c:8955
 dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8969
 do_setlink+0x8b3/0x41f0 net/core/rtnetlink.c:2839
 __rtnl_newlink net/core/rtnetlink.c:3680 [inline]
 rtnl_newlink+0x180b/0x20a0 net/core/rtnetlink.c:3727
 rtnetlink_rcv_msg+0x89b/0x10d0 net/core/rtnetlink.c:6595
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2559
 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
 netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1361
 netlink_sendmsg+0x8e1/0xcb0 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 __sys_sendto+0x3a4/0x4f0 net/socket.c:2191
 __do_sys_sendto net/socket.c:2203 [inline]
 __se_sys_sendto net/socket.c:2199 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2199
 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
RIP: 0033:0x7fca2507f99c
Code: 1a 51 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 60 51 02 00 48 8b
RSP: 002b:00007fffab9af660 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fca25cd4620 RCX: 00007fca2507f99c
RDX: 000000000000002c RSI: 00007fca25cd4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007fffab9af6b4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fca25cd4670 R15: 0000000000000000
 </TASK>