INFO: task syz-executor:5826 blocked for more than 143 seconds. Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:21800 pid:5826 tgid:5826 ppid:1 task_flags:0x400140 flags:0x00004006 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 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917 __mutex_lock_common kernel/locking/mutex.c:678 [inline] __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:746 lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1444 jfs_umount+0x2ef/0x3c0 fs/jfs/jfs_umount.c:114 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194 generic_shutdown_super+0x132/0x2c0 fs/super.c:642 kill_block_super+0x44/0x90 fs/super.c:1710 deactivate_locked_super+0xbc/0x130 fs/super.c:473 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1431 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50 exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x9a/0x120 kernel/entry/common.c:218 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbc7b58fc97 RSP: 002b:00007ffd22b18f08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007fbc7b61089d RCX: 00007fbc7b58fc97 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd22b18fc0 RBP: 00007ffd22b18fc0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd22b1a050 R13: 00007fbc7b61089d R14: 0000000000021338 R15: 00007ffd22b1a090 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8df3dee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764 3 locks held by kworker/u8:2/36: 3 locks held by kworker/u8:4/63: #0: ffff88801a089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline] #0: ffff88801a089148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b1/0x17a0 kernel/workqueue.c:3319 #1: ffffc90001557c60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline] #1: ffffc90001557c60 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ec/0x17a0 kernel/workqueue.c:3319 #2: ffffffff8f2e8588 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 2 locks held by getty/5587: #0: ffff88814d36d0a0 (&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/5816: #0: ffff888031cbe0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888031cbe0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888031cbe0e0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffffffff8e36ade8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1444 2 locks held by syz-executor/5826: #0: ffff888058fac0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888058fac0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888058fac0e0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffffffff8e36ade8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1444 2 locks held by syz-executor/6465: #0: ffff88805095a0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff88805095a0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff88805095a0e0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffffffff8e36ade8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1444 2 locks held by syz-executor/6680: #0: ffff888027a6c0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888027a6c0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888027a6c0e0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffffffff8e36ade8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1444 2 locks held by syz-executor/7958: #0: ffff888032ba00e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888032ba00e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline] #0: ffff888032ba00e0 (&type->s_umount_key#71){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505 #1: ffffffff8e36ade8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1444 1 lock held by syz.0.288/8744: #0: ffff888031cbe0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888031cbe0e0 (&type->s_umount_key#71){++++}-{4:4}, at: super_lock+0x25c/0x3b0 fs/super.c:120 1 lock held by syz.3.304/8904: #0: ffff888058fac0e0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline] #0: ffff888058fac0e0 (&type->s_umount_key#71){++++}-{4:4}, at: super_lock+0x25c/0x3b0 fs/super.c:120 1 lock held by syz-executor/9245: #0: ffffffff8df439b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline] #0: ffffffff8df439b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b7/0x730 kernel/rcu/tree_exp.h:998 3 locks held by syz-executor/9490: #0: ffffffff8ea81fe0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8ea81fe0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8ea81fe0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f2e8588 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f2e8588 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f2e8588 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4064 #2: ffffffff8df439b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:304 [inline] #2: ffffffff8df439b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f4/0x730 kernel/rcu/tree_exp.h:998 2 locks held by syz.8.349/9518: 1 lock held by syz.9.355/9497: 1 lock held by rm/9537: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #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+0x711/0x8a0 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: 9490 Comm: syz-executor Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:preempt_count_add+0x6a/0x1a0 kernel/sched/core.c:5860 Code: e1 10 48 c7 c0 a0 c6 7d 99 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 ec 00 00 00 83 3d 2f d7 ec 17 00 75 11 65 8b 05 b6 b0 e1 10 <0f> b6 c0 3d f5 00 00 00 73 5e 65 8b 05 a5 b0 e1 10 25 ff ff ff 7f RSP: 0018:ffffc90003336630 EFLAGS: 00000046 RAX: 0000000080000003 RBX: 0000000000000899 RCX: ffffffff997dc603 RDX: 00000000000000b6 RSI: ffffffff8bc12060 RDI: 0000000000000001 RBP: 0000000000000001 R08: ffff8880242a8237 R09: 1ffff11004855046 R10: dffffc0000000000 R11: ffffffff8b4e5840 R12: 1ffffffff3364392 R13: 00000000ffffffff R14: 000000b691a183c0 R15: dffffc0000000000 FS: 000055555bd39500(0000) GS:ffff8881261f6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffdf0017dac CR3: 000000007b910000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: delay_tsc+0x65/0xc0 arch/x86/lib/delay.c:79 udelay include/asm-generic/delay.h:62 [inline] wait_for_lsr+0x160/0x2f0 drivers/tty/serial/8250/8250_port.c:2104 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+0x728/0xc40 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 _printk+0xcf/0x120 kernel/printk/printk.c:2475 br_set_state+0x475/0x710 net/bridge/br_stp.c:57 new_nbp+0x303/0x440 net/bridge/br_if.c:443 br_add_if+0x28e/0xec0 net/bridge/br_if.c:599 do_set_master+0x533/0x6d0 net/core/rtnetlink.c:2946 do_setlink+0xd47/0x40d0 net/core/rtnetlink.c:3159 rtnl_changelink net/core/rtnetlink.c:3769 [inline] __rtnl_newlink net/core/rtnetlink.c:3928 [inline] rtnl_newlink+0x160b/0x1c70 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x21c/0x490 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:727 __sys_sendto+0x3bd/0x520 net/socket.c:2180 __do_sys_sendto net/socket.c:2187 [inline] __se_sys_sendto net/socket.c:2183 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2183 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: 0033:0x7f14075907fc Code: 2a 5f 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 70 5f 02 00 48 8b RSP: 002b:00007ffc78e5fa40 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f14082e4620 RCX: 00007f14075907fc RDX: 0000000000000028 RSI: 00007f14082e4670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffc78e5fa94 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f14082e4670 R15: 0000000000000000