INFO: task syz.1.4675:22134 blocked for more than 143 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.4675 state:D stack:26080 pid:22134 tgid:22129 ppid:16626 task_flags:0x40054c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591 mmap_write_lock include/linux/mmap_lock.h:335 [inline] exit_mmap+0x27b/0xb10 mm/mmap.c:1285 __mmput+0x118/0x430 kernel/fork.c:1173 exit_mm+0x169/0x230 kernel/exit.c:581 do_exit+0x627/0x22f0 kernel/exit.c:959 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 get_signal+0x1285/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f01df78f749 RSP: 002b:00007f01e05e8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: fffffffffffffffc RBX: 00007f01df9e5fa0 RCX: 00007f01df78f749 RDX: 0000000000000050 RSI: 0000200000000600 RDI: 000000000000000a RBP: 00007f01df813f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f01df9e6038 R14: 00007f01df9e5fa0 R15: 00007ffccda5b208 INFO: task syz.4.4681:22152 blocked for more than 143 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.4681 state:D stack:26464 pid:22152 tgid:22148 ppid:15790 task_flags:0x40054c flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591 mmap_write_lock include/linux/mmap_lock.h:335 [inline] exit_mmap+0x27b/0xb10 mm/mmap.c:1285 __mmput+0x118/0x430 kernel/fork.c:1173 exit_mm+0x169/0x230 kernel/exit.c:581 do_exit+0x627/0x22f0 kernel/exit.c:959 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 get_signal+0x1285/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4027b8f749 RSP: 002b:00007f4028a8f0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f4027de5fa8 RCX: 00007f4027b8f749 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f4027de5fa8 RBP: 00007f4027de5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4027de6038 R14: 00007fff2a114220 R15: 00007fff2a114308 INFO: task syz.0.4680:22150 blocked for more than 143 seconds. Not tainted syzkaller #0 Blocked by coredump. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.4680 state:D stack:24008 pid:22150 tgid:22149 ppid:16944 task_flags:0x40054c flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591 mmap_write_lock include/linux/mmap_lock.h:335 [inline] exit_mmap+0x27b/0xb10 mm/mmap.c:1285 __mmput+0x118/0x430 kernel/fork.c:1173 exit_mm+0x169/0x230 kernel/exit.c:581 do_exit+0x627/0x22f0 kernel/exit.c:959 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 get_signal+0x1285/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7efd0298f749 RSP: 002b:00007efd0379d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007efd02be5fa8 RCX: 00007efd0298f749 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007efd02be5fa8 RBP: 00007efd02be5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007efd02be6038 R14: 00007ffe56c735d0 R15: 00007ffe56c736b8 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 1 lock held by kworker/u8:13/4040: #0: ffff8880b863a918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:639 1 lock held by klogd/5188: #0: ffff8880b863a918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:639 2 locks held by getty/5588: #0: ffff88803476d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211 1 lock held by syz-executor/5816: #0: ffff888077d64cc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:353 [inline] #0: ffff888077d64cc0 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x211/0x4d0 mm/util.c:579 1 lock held by syz-executor/16626: #0: ffff88801e3da800 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:335 [inline] #0: ffff88801e3da800 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x27b/0xb10 mm/mmap.c:1285 1 lock held by syz.1.4675/22134: #0: ffff88802be58340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:335 [inline] #0: ffff88802be58340 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x27b/0xb10 mm/mmap.c:1285 1 lock held by syz.4.4681/22152: #0: ffff888077d60340 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:335 [inline] #0: ffff888077d60340 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x27b/0xb10 mm/mmap.c:1285 1 lock held by syz.0.4680/22150: #0: ffff888079336540 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:335 [inline] #0: ffff888079336540 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x27b/0xb10 mm/mmap.c:1285 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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:160 [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+0xf95/0xfe0 kernel/hung_task.c:515 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 10132 Comm: kworker/u8:11 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events_unbound nsim_dev_trap_report_work RIP: 0010:check_wait_context kernel/locking/lockdep.c:4868 [inline] RIP: 0010:__lock_acquire+0x459/0x2cf0 kernel/locking/lockdep.c:5187 Code: 84 c9 0f b6 d3 0f b6 c9 0f 44 ca 89 0c 24 45 8b a6 28 0b 00 00 41 8d 4c 24 ff 83 f9 ff 41 bd ff ff ff ff 44 0f 4c e9 41 ff c5 <41> 8d 5c 24 01 49 ff cc 89 d9 83 c1 fe 78 40 45 89 e7 41 81 e7 ff RSP: 0018:ffffc900031d7270 EFLAGS: 00000057 RAX: 0000000000020007 RBX: 0000000000000003 RCX: 0000000000000003 RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88807cb36750 R08: ffffffff8173fd65 R09: ffffffff8df41aa0 R10: ffffc900031d7578 R11: ffffffff81acf3d0 R12: 0000000000000004 R13: 0000000000000000 R14: ffff88807cb35b80 R15: ffff88807cb366b0 FS: 0000000000000000(0000) GS:ffff888125e21000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fac059b42f8 CR3: 000000000dd3a000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_node_noprof+0x43c/0x720 mm/slub.c:5315 __alloc_skb+0x1dc/0x3a0 net/core/skbuff.c:679 alloc_skb include/linux/skbuff.h:1383 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:818 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:875 [inline] nsim_dev_trap_report_work+0x29a/0xb80 drivers/net/netdevsim/dev.c:921 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246