INFO: task syz-executor:4276 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22144 pid:4276 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 io_schedule+0x7c/0xd0 kernel/sched/core.c:8797 folio_wait_bit_common+0x6e1/0xf60 mm/filemap.c:1324 truncate_inode_pages_range+0x9a2/0xff0 mm/truncate.c:422 evict+0x498/0x870 fs/inode.c:707 dispose_list fs/inode.c:738 [inline] evict_inodes+0x604/0x690 fs/inode.c:792 generic_shutdown_super+0x93/0x340 fs/super.c:480 kill_block_super+0x7c/0xe0 fs/super.c:1470 deactivate_locked_super+0x93/0xf0 fs/super.c:332 cleanup_mnt+0x463/0x4f0 fs/namespace.c:1191 task_work_run+0x1ca/0x250 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f180c7902f7 RSP: 002b:00007ffcb0520648 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f180c811d7d RCX: 00007f180c7902f7 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffcb0520700 RBP: 00007ffcb0520700 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffcb0521790 R13: 00007f180c811d7d R14: 0000000000024f2c R15: 00007ffcb05217d0 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2b630 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8cb2be50 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/28: #0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 2 locks held by getty/4031: #0: ffff88807e250098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198 1 lock held by syz-executor/4276: #0: ffff8880761600e0 (&type->s_umount_key#73){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362 1 lock held by udevd/4456: #0: ffff888024974360 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_simple_ioctl drivers/block/loop.c:1507 [inline] #0: ffff888024974360 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_ioctl+0x524/0x1bf0 drivers/block/loop.c:1583 1 lock held by syz.5.2790/10766: #0: ffff888024974360 (&lo->lo_mutex){+.+.}-{3:3}, at: loop_set_status+0x2a/0x910 drivers/block/loop.c:1265 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xeee/0xf30 kernel/hung_task.c:377 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6281 Comm: kworker/u4:16 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:for_each_canary mm/kfence/core.c:-1 [inline] RIP: 0010:kfence_guarded_alloc+0x754/0xcf0 mm/kfence/core.c:439 Code: 10 73 3d 4c 89 f0 48 c1 e8 03 42 0f b6 04 20 84 c0 75 19 44 89 f0 24 07 34 aa 41 88 06 49 ff c6 49 39 de 73 22 e8 7c a0 af ff d7 44 89 f1 80 e1 07 38 c1 7c dd 4c 89 f7 e8 88 cf ff ff eb d3 RSP: 0018:ffffc900039f76a0 EFLAGS: 00000293 RAX: ffffffff81d135e4 RBX: ffff88823bd97000 RCX: ffff888075ce0000 RDX: 0000000000000000 RSI: ffff88823bd97000 RDI: ffff88823bd960f0 RBP: ffffc900039f77b0 R08: dffffc0000000000 R09: fffff940011decb1 R10: fffff940011decb1 R11: 1ffffd40011decb0 R12: dffffc0000000000 R13: ffff88823bd96000 R14: ffff88823bd96f31 R15: ffff88814018f280 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e81fff8 CR3: 000000000c88e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __kfence_alloc+0x369/0x3a0 mm/kfence/core.c:1050 kfence_alloc include/linux/kfence.h:128 [inline] slab_alloc_node mm/slub.c:3283 [inline] kmem_cache_alloc_node+0x2b5/0x320 mm/slub.c:3404 __alloc_skb+0xfc/0x7e0 net/core/skbuff.c:505 alloc_skb include/linux/skbuff.h:1271 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] nsim_dev_trap_report_work+0x28f/0xaf0 drivers/net/netdevsim/dev.c:851 process_one_work+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295