INFO: task syz.1.15:6040 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.15 state:D stack:25688 pid:6040 tgid:6017 ppid:5793 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7289 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244 inode_lock_nested include/linux/fs.h:1073 [inline] __start_dirop fs/namei.c:2929 [inline] start_dirop fs/namei.c:2940 [inline] filename_create+0x200/0x370 fs/namei.c:4928 filename_mkdirat+0xd2/0x520 fs/namei.c:5265 __do_sys_mkdirat fs/namei.c:5293 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5290 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f25868bb687 RSP: 002b:00007f2584aece58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f2584aecee0 RCX: 00007f25868bb687 RDX: 00000000000001ff RSI: 0000200000000100 RDI: 00000000ffffff9c RBP: 0000000000000000 R08: 0000200000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000100 R13: 00007f2584aecea0 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/37: #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8ddcb9c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 9 locks held by kworker/u8:2/42: 4 locks held by kworker/u8:5/146: #0: ffff88801ee9c138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #0: ffff88801ee9c138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359 #1: ffffc90003a6fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline] #1: ffffc90003a6fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359 #2: ffff8880250560d0 (&type->s_umount_key#55){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565 #3: ffff8880621c28e8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 4 locks held by kworker/u8:9/1137: #0: ffff88801ee9c138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #0: ffff88801ee9c138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359 #1: ffffc90005e27c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline] #1: ffffc90005e27c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359 #2: ffff888037b340d0 (&type->s_umount_key#32){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565 #3: ffff888037b14cd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: percpu_down_read include/linux/percpu-rwsem.h:77 [inline] #3: ffff888037b14cd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_read fs/ext4/ext4.h:1814 [inline] #3: ffff888037b14cd8 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages+0x205/0x3b0 fs/ext4/inode.c:3028 4 locks held by kworker/u8:10/1157: 3 locks held by kworker/u8:11/2996: #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #0: ffff888019c44138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359 #1: ffffc9000e90fc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline] #1: ffffc9000e90fc40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359 #2: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 3 locks held by kworker/u8:12/4515: #0: ffff8880320fa138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #0: ffff8880320fa138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359 #1: ffffc9001129fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline] #1: ffffc9001129fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359 #2: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x124/0x1680 net/ipv6/addrconf.c:4198 2 locks held by dhcpcd/5457: #0: ffffffff8f13e078 (vlan_ioctl_mutex){+.+.}-{4:4}, at: sock_ioctl+0x644/0x7f0 net/socket.c:1337 #1: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: vlan_ioctl_handler+0xf0/0x630 net/8021q/vlan.c:579 2 locks held by getty/5555: #0: ffff8880377370a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211 4 locks held by syz.1.15/6018: 2 locks held by syz.1.15/6040: #0: ffff888025056480 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff8880621c2cb8 (&type->i_mutex_dir_key#9/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff8880621c2cb8 (&type->i_mutex_dir_key#9/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2929 [inline] #1: ffff8880621c2cb8 (&type->i_mutex_dir_key#9/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2940 [inline] #1: ffff8880621c2cb8 (&type->i_mutex_dir_key#9/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4928 1 lock held by syz-executor/7533: #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4093 1 lock held by syz-executor/7567: #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x65f/0xe30 net/ipv6/addrconf.c:5031 1 lock held by syz-executor/7687: #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4093 1 lock held by syz-executor/7729: #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x65f/0xe30 net/ipv6/addrconf.c:5031 1 lock held by syz-executor/7733: #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f15cb38 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4093 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xfd9/0x1030 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 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: 6018 Comm: syz.1.15 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x28/0x80 kernel/kcov.c:217 Code: 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 0d 88 1f 8a 10 65 8b 35 a9 1f 8a 10 81 e6 00 00 ff 00 ba 00 01 00 00 23 91 a4 0b 00 00 <89> d7 09 f7 74 11 85 f6 75 39 85 d2 74 35 83 b9 74 16 00 00 00 74 RSP: 0000:ffffc90005cd7680 EFLAGS: 00000246 RAX: ffffffff83529546 RBX: 0000000000000004 RCX: ffff888032f2bd00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000080000 RBP: ffff88803f1e2000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: 1ffff11007e3c400 R14: 0000000000000000 R15: 1ffff11007e3c402 FS: 00007f2584b0e6c0(0000) GS:ffff888126436000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd32f635e9c CR3: 0000000035dca000 CR4: 00000000003526f0 Call Trace: dtSplitRoot+0x7a6/0x16c0 fs/jfs/jfs_dtree.c:1981 dtSplitUp fs/jfs/jfs_dtree.c:993 [inline] dtInsert+0xf19/0x5f10 fs/jfs/jfs_dtree.c:871 jfs_mkdir+0x783/0xb00 fs/jfs/namei.c:271 vfs_mkdir+0x40b/0x630 fs/namei.c:5239 filename_mkdirat+0x289/0x520 fs/namei.c:5272 __do_sys_mkdirat fs/namei.c:5293 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5290 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f25868bb687 Code: 00 66 90 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 db f7 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 b8 02 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f2584b0de58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f2584b0dee0 RCX: 00007f25868bb687 RDX: 00000000000001ff RSI: 0000200000000800 RDI: 00000000ffffff9c RBP: 00002000000007c0 R08: 0000200000000c00 R09: 0000000000000000 R10: 00002000000007c0 R11: 0000000000000246 R12: 0000200000000800 R13: 00007f2584b0dea0 R14: 0000000000000000 R15: 0000200000000980