INFO: task syz.0.35:4548 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.35 state:D stack:25728 pid:4548 ppid:4400 flags:0x00004000 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 rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189 mmap_write_lock include/linux/mmap_lock.h:71 [inline] exit_mmap+0x20f/0x8e0 mm/mmap.c:3258 __mmput+0x118/0x3c0 kernel/fork.c:1200 exit_mm+0x1e6/0x2c0 kernel/exit.c:565 do_exit+0x8c1/0x2400 kernel/exit.c:867 do_group_exit+0x217/0x2d0 kernel/exit.c:1022 get_signal+0x1272/0x1350 kernel/signal.c:2871 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 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: 0033:0x7f2eff78f6c9 RSP: 002b:00007f2f005480e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f2eff9e5fa8 RCX: 00007f2eff78f6c9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f2eff9e5fa8 RBP: 00007f2eff9e5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2eff9e6038 R14: 00007ffeda6ae770 R15: 00007ffeda6ae858 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/27: #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 kworker/u4:2/32: #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc90000a97d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 1 lock held by dhcpcd/3932: #0: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x248b/0x4020 kernel/fork.c:2446 2 locks held by getty/4031: #0: ffff88802f51d098 (&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 udevd/4296: #0: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827 1 lock held by udevd/4298: #0: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827 2 locks held by kworker/u4:5/4385: #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 #1: ffffc900040e7d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267 1 lock held by syz-executor/4408: #0: ffff88807d60bd58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline] #0: ffff88807d60bd58 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x20f/0x8e0 mm/mmap.c:3258 1 lock held by modprobe/4543: #0: ffff88802fb362d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline] #0: ffff88802fb362d8 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x15d/0x2b0 mm/util.c:518 1 lock held by modprobe/4544: #0: ffff88807d8808d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline] #0: ffff88807d8808d8 (&mm->mmap_lock){++++}-{3:3}, at: do_mprotect_pkey+0x22b/0xa40 mm/mprotect.c:702 1 lock held by syz.0.35/4548: #0: ffff88807d883d58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline] #0: ffff88807d883d58 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x20f/0x8e0 mm/mmap.c:3258 1 lock held by syz-executor/5327: #0: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827 2 locks held by syz-executor/5330: #0: ffffffff8cbc5010 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:593 [inline] #0: ffffffff8cbc5010 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1541 [inline] #0: ffffffff8cbc5010 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x2a9/0x15c0 kernel/fork.c:1590 #1: ffff888079e41058 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline] #1: ffff888079e41058 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:594 [inline] #1: ffff888079e41058 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1541 [inline] #1: ffff888079e41058 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x2c3/0x15c0 kernel/fork.c:1590 7 locks held by syz-executor/5336: #0: ffff8880239ac460 (sb_writers#11){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580 #1: ffff88802e07cc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e3/0x520 fs/kernfs/file.c:343 #2: ffffffff8cb536e8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:442 [inline] #2: ffffffff8cb536e8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1700 #3: ffffffff8c9c7b30 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2476 [inline] #3: ffffffff8c9c7b30 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x183/0x600 kernel/cgroup/cgroup.c:2982 #4: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2478 [inline] #4: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x199/0x600 kernel/cgroup/cgroup.c:2982 #5: ffffffff8cb61d68 (cpuset_mutex){+.+.}-{3:3}, at: cpuset_attach+0xac/0x540 kernel/cgroup/cpuset.c:2647 #6: ffff888079e453d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline] #6: ffff888079e453d8 (&mm->mmap_lock){++++}-{3:3}, at: mpol_rebind_mm+0xbe/0x370 mm/mempolicy.c:386 1 lock held by syz.1.494/5517: #0: ffff88807d609058 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline] #0: ffff88807d609058 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x20f/0x8e0 mm/mmap.c:3258 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 27 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 46 Comm: kworker/u4:3 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:memset+0x2d/0x40 mm/kasan/shadow.c:47 Code: 53 48 89 d3 89 f5 49 89 fe 48 8b 4c 24 18 48 89 d6 ba 01 00 00 00 e8 72 ec ff ff 84 c0 74 11 4c 89 f7 89 ee 48 89 da 5b 41 5e <5d> e9 8d 28 3b 08 31 c0 5b 41 5e 5d c3 66 0f 1f 44 00 00 41 57 41 RSP: 0018:ffffc90000b777c0 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffff88807d4cd4b0 RCX: ffffffff81d0dc4c RDX: 0000000000000200 RSI: 0000000000000000 RDI: ffffc90000b777d0 RBP: 0000000000000000 R08: dffffc0000000000 R09: fffff5200016ef3a R10: 0000000000000000 R11: 0000000000000038 R12: 0000000000000001 R13: ffff8881401e3500 R14: 0000000000000a20 R15: ffffc90000b777d0 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c00141f008 CR3: 000000007e013000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kasan_save_stack mm/kasan/common.c:42 [inline] kasan_set_track+0x3c/0x70 mm/kasan/common.c:52 __kasan_slab_alloc+0x6b/0x80 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737 slab_alloc_node mm/slub.c:3359 [inline] kmem_cache_alloc_node+0x14d/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