INFO: task syz.3.20:6646 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.20 state:D stack:28296 pid:6646 tgid:6645 ppid:6394 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5254 [inline] __schedule+0x17c4/0x4d60 kernel/sched/core.c:6862 __schedule_loop kernel/sched/core.c:6944 [inline] schedule+0x165/0x360 kernel/sched/core.c:6959 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7016 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 chrdev_open+0x4cc/0x5e0 fs/char_dev.c:414 do_dentry_open+0x953/0x13f0 fs/open.c:965 vfs_open+0x3b/0x340 fs/open.c:1097 do_open fs/namei.c:3975 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4134 do_filp_open+0x1fa/0x410 fs/namei.c:4161 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1f2838efc9 RSP: 002b:00007f1f29162038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f1f285e5fa0 RCX: 00007f1f2838efc9 RDX: 0000000000101001 RSI: 0000200000000440 RDI: 00000000ffffff9c RBP: 00007f1f28411f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1f285e6038 R14: 00007f1f285e5fa0 R15: 00007ffc7012f0d8 INFO: task syz.2.19:6654 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.19 state:D stack:27944 pid:6654 tgid:6653 ppid:6392 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5254 [inline] __schedule+0x17c4/0x4d60 kernel/sched/core.c:6862 __schedule_loop kernel/sched/core.c:6944 [inline] schedule+0x165/0x360 kernel/sched/core.c:6959 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7016 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 chrdev_open+0x4cc/0x5e0 fs/char_dev.c:414 do_dentry_open+0x953/0x13f0 fs/open.c:965 vfs_open+0x3b/0x340 fs/open.c:1097 do_open fs/namei.c:3975 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4134 do_filp_open+0x1fa/0x410 fs/namei.c:4161 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff71338efc9 RSP: 002b:00007ff714289038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ff7135e5fa0 RCX: 00007ff71338efc9 RDX: 0000000000101001 RSI: 0000200000000440 RDI: 00000000ffffff9c RBP: 00007ff713411f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff7135e6038 R14: 00007ff7135e5fa0 R15: 00007ffed0de2fe8 INFO: task syz.0.17:6658 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.17 state:D stack:28296 pid:6658 tgid:6657 ppid:6389 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5254 [inline] __schedule+0x17c4/0x4d60 kernel/sched/core.c:6862 __schedule_loop kernel/sched/core.c:6944 [inline] schedule+0x165/0x360 kernel/sched/core.c:6959 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7016 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 chrdev_open+0x4cc/0x5e0 fs/char_dev.c:414 do_dentry_open+0x953/0x13f0 fs/open.c:965 vfs_open+0x3b/0x340 fs/open.c:1097 do_open fs/namei.c:3975 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4134 do_filp_open+0x1fa/0x410 fs/namei.c:4161 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f614ef8efc9 RSP: 002b:00007f614fd46038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f614f1e5fa0 RCX: 00007f614ef8efc9 RDX: 0000000000101001 RSI: 0000200000000440 RDI: 00000000ffffff9c RBP: 00007f614f011f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f614f1e6038 R14: 00007f614f1e5fa0 R15: 00007ffcf1faafc8 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e33d960 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e33d960 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e33d960 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5587: #0: ffff88803505d0a0 (&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+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by syz.1.18/6633: 1 lock held by syz.3.20/6646: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.2.19/6654: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.0.17/6658: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.4.21/6841: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.5.22/6875: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.6.23/6878: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.7.24/6881: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.8.25/6914: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.9.26/6975: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.1.27/6986: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.0.28/6989: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.2.29/7013: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.3.30/7070: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.4.31/7090: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.5.32/7093: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.6.33/7124: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.7.34/7173: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.9.36/7208: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.8.35/7211: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.1.37/7233: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.0.38/7267: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.2.39/7313: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.3.40/7316: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.4.41/7338: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.5.42/7368: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.6.43/7423: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.7.44/7444: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.8.45/7452: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 1 lock held by syz.9.46/7480: #0: ffff88802f86c0f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_open+0xc0/0x5f0 drivers/comedi/comedi_fops.c:2863 ============================================= 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 10/02/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 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] check_hung_uninterruptible_tasks kernel/hung_task.c:337 [inline] watchdog+0xfa9/0xff0 kernel/hung_task.c:500 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 2977 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet RIP: 0010:unwind_next_frame+0x395/0x2390 arch/x86/kernel/unwind_orc.c:505 Code: e0 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 6d 19 00 00 4c 89 e8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 80 19 00 00 41 0f b6 44 24 01 <83> e0 07 0f 84 75 15 00 00 83 f8 01 4c 8b 7c 24 48 48 bd 00 00 00 RSP: 0018:ffffc9000b337378 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffffffff8fdaf40c RCX: ffffffff8fdaf410 RDX: ffffffff905a9efc RSI: ffffffff905a9efc RDI: ffffffff8be0f060 RBP: dffffc0000000000 R08: 0000000000000009 R09: ffffffff81741f85 R10: ffffc9000b337498 R11: ffffffff81ad0160 R12: ffffffff905a9f00 R13: ffffffff905a9f01 R14: ffffc9000b337448 R15: ffffffff8fdaf40c FS: 0000000000000000(0000) GS:ffff888125a9c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555934d85c8 CR3: 000000000e138000 CR4: 00000000003526f0 Call Trace: 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:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5650 [inline] __kmalloc_node_track_caller_noprof+0x571/0x810 mm/slub.c:5759 kmalloc_reserve+0x136/0x290 net/core/skbuff.c:604 pskb_expand_head+0x18e/0x1150 net/core/skbuff.c:2253 __skb_cow include/linux/skbuff.h:3853 [inline] skb_cow_head include/linux/skbuff.h:3887 [inline] batadv_skb_head_push+0x169/0x200 net/batman-adv/mesh-interface.c:71 batadv_send_skb_packet+0xc8/0x690 net/batman-adv/send.c:81 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:391 [inline] batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:419 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0x62f/0x7e0 net/batman-adv/bat_iv_ogm.c:1697 process_one_work+0x94a/0x15d0 kernel/workqueue.c:3267 process_scheduled_works kernel/workqueue.c:3350 [inline] worker_thread+0x9b0/0xee0 kernel/workqueue.c:3431 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245