INFO: task syz.0.17:6022 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.17 state:D stack:28976 pid:6022 tgid:6020 ppid:5973 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115 rwsem_down_write_slowpath+0x524/0x1310 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write+0x1d6/0x200 kernel/locking/rwsem.c:1591 inode_lock include/linux/fs.h:870 [inline] vfs_utimes+0x3b7/0x820 fs/utimes.c:65 do_utimes_path fs/utimes.c:99 [inline] do_utimes fs/utimes.c:140 [inline] __do_sys_utime fs/utimes.c:221 [inline] __se_sys_utime fs/utimes.c:210 [inline] __x64_sys_utime+0x1e2/0x2c0 fs/utimes.c:210 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fabd158eba9 RSP: 002b:00007fabd0bdd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000084 RAX: ffffffffffffffda RBX: 00007fabd17d6090 RCX: 00007fabd158eba9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000000c0 RBP: 00007fabd1611e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fabd17d6128 R14: 00007fabd17d6090 R15: 00007ffd32e714b8 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e5c15a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e5c15a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e5c15a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 2 locks held by getty/5612: #0: ffff88814d96d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 2 locks held by syz.0.17/6021: #0: ffff8880787b6428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153 #1: ffff88805bdb8148 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188 2 locks held by syz.0.17/6022: #0: ffff8880787b6428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36 #1: ffff88805bdb8148 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #1: ffff88805bdb8148 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65 2 locks held by syz.1.18/6047: #0: ffff888074228428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153 #1: ffff88805bdb87b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188 2 locks held by syz.1.18/6049: #0: ffff888074228428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36 #1: ffff88805bdb87b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #1: ffff88805bdb87b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65 2 locks held by syz.2.20/6077: #0: ffff888032842428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153 #1: ffff88805f8c07b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188 2 locks held by syz.2.20/6079: #0: ffff888032842428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36 #1: ffff88805f8c07b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #1: ffff88805f8c07b8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65 2 locks held by syz.3.21/6103: #0: ffff888078172428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153 #1: ffff88805bdb8e28 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188 2 locks held by syz.3.21/6104: #0: ffff888078172428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36 #1: ffff88805bdb8e28 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #1: ffff88805bdb8e28 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65 2 locks held by syz.4.22/6133: #0: ffff888076a00428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153 #1: ffff88805bdb9498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188 2 locks held by syz.4.22/6134: #0: ffff888076a00428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36 #1: ffff88805bdb9498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #1: ffff88805bdb9498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65 2 locks held by syz.5.23/6168: #0: ffff88806b6da428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153 #1: ffff88805bdb9b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188 2 locks held by syz.5.23/6169: #0: ffff88806b6da428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36 #1: ffff88805bdb9b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #1: ffff88805bdb9b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65 2 locks held by syz.6.26/6203: #0: ffff888059288428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153 #1: ffff88805bdba178 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188 2 locks held by syz.6.26/6204: #0: ffff888059288428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36 #1: ffff88805bdba178 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #1: ffff88805bdba178 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65 2 locks held by syz.7.27/6232: #0: ffff88805cc2a428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153 #1: ffff88805f8c1b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188 2 locks held by syz.7.27/6234: #0: ffff88805cc2a428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36 #1: ffff88805f8c1b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #1: ffff88805f8c1b08 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65 2 locks held by syz.8.28/6264: #0: ffff88807b296428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153 #1: ffff88805bdba7e8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188 2 locks held by syz.8.28/6265: #0: ffff88807b296428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36 #1: ffff88805bdba7e8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #1: ffff88805bdba7e8 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65 2 locks held by syz.9.29/6301: #0: ffff88805912a428 (sb_writers#13){.+.+}-{0:0}, at: do_pwritev+0x1a6/0x270 fs/read_write.c:1153 #1: ffff88805f8c1498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: netfs_start_io_direct+0x116/0x260 fs/netfs/locking.c:188 2 locks held by syz.9.29/6302: #0: ffff88805912a428 (sb_writers#13){.+.+}-{0:0}, at: vfs_utimes+0x69b/0x820 fs/utimes.c:36 #1: ffff88805f8c1498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #1: ffff88805f8c1498 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_utimes+0x3b7/0x820 fs/utimes.c:65 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf0e/0x1260 kernel/hung_task.c:491 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148 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: 49 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:iterate_chain_key kernel/locking/lockdep.c:451 [inline] RIP: 0010:__lock_acquire+0x642/0x1ce0 kernel/locking/lockdep.c:5225 Code: 08 45 85 d2 0f 85 6f 04 00 00 4c 89 e7 89 4c 24 08 e8 92 ac ff ff 8b 4c 24 08 48 83 78 40 00 0f 84 c2 0a 00 00 0f b7 44 24 10 <8b> 7c 24 28 44 8b 74 24 20 c1 e0 0d 66 0b 04 24 98 29 f8 8b 7c 24 RSP: 0018:ffffc90000b97958 EFLAGS: 00000086 RAX: 0000000000000700 RBX: ffff888022ae2f30 RCX: 00000000748bd351 RDX: 0000000000000000 RSI: ffff888022ae2f80 RDI: ffff888022ae2f80 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000002 R11: 0000000000000000 R12: ffff888022ae2f80 R13: ffff888022ae2440 R14: 0000000000000002 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff8881247b2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055fb93cf9be0 CR3: 000000000e380000 CR4: 00000000003526f0 Call Trace: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:356 [inline] batadv_nc_purge_paths+0xd9/0x3a0 net/batman-adv/network-coding.c:442 batadv_nc_worker+0x958/0x1030 net/batman-adv/network-coding.c:722 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245