INFO: task syz.3.447:7186 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.447 state:D stack:26952 pid:7186 tgid:7184 ppid:5857 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7118 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 bdev_open+0xe0/0xd30 block/bdev.c:945 bdev_file_open_by_dev+0x1be/0x240 block/bdev.c:1059 swsusp_check+0x56/0x440 kernel/power/swap.c:1577 software_resume+0x51/0x420 kernel/power/hibernate.c:1039 resume_store+0x2f1/0x460 kernel/power/hibernate.c:1324 kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c6/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 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: 0033:0x7f4cb418eba9 RSP: 002b:00007f4cb4f62038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f4cb43d6090 RCX: 00007f4cb418eba9 RDX: 0000000000032600 RSI: 0000200000000000 RDI: 0000000000000008 RBP: 00007f4cb4211e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4cb43d6128 R14: 00007f4cb43d6090 R15: 00007ffe58e5ae58 INFO: task syz.1.452:7205 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.452 state:D stack:26880 pid:7205 tgid:7204 ppid:5855 task_flags:0x408140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7118 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 lock_system_sleep+0x4a/0x70 kernel/power/main.c:57 snapshot_open+0x27/0x280 kernel/power/user.c:56 misc_open+0x2d5/0x350 drivers/char/misc.c:163 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:1095 do_open fs/namei.c:3895 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4054 do_filp_open+0x1fa/0x410 fs/namei.c:4081 do_sys_openat2+0x121/0x1c0 fs/open.c:1435 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1461 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: 0033:0x7f57c438eba9 RSP: 002b:00007f57c52da038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f57c45d5fa0 RCX: 00007f57c438eba9 RDX: 0000000000086000 RSI: 0000200000000300 RDI: ffffffffffffff9c RBP: 00007f57c4411e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f57c45d6038 R14: 00007f57c45d5fa0 R15: 00007ffd288c54b8 INFO: task syz.2.453:7208 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.453 state:D stack:27200 pid:7208 tgid:7207 ppid:5858 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7118 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 misc_open+0x51/0x350 drivers/char/misc.c:125 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:1095 do_open fs/namei.c:3895 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4054 do_filp_open+0x1fa/0x410 fs/namei.c:4081 do_sys_openat2+0x121/0x1c0 fs/open.c:1435 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1461 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: 0033:0x7fdbb318eba9 RSP: 002b:00007fdbb4053038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fdbb33d5fa0 RCX: 00007fdbb318eba9 RDX: 0000000000000000 RSI: 0000200000000100 RDI: ffffffffffffff9c RBP: 00007fdbb3211e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdbb33d6038 R14: 00007fdbb33d5fa0 R15: 00007fffdbf31588 INFO: task syz.0.455:7214 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.455 state:D stack:27240 pid:7214 tgid:7213 ppid:5856 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7118 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 misc_open+0x51/0x350 drivers/char/misc.c:125 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:1095 do_open fs/namei.c:3895 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4054 do_filp_open+0x1fa/0x410 fs/namei.c:4081 do_sys_openat2+0x121/0x1c0 fs/open.c:1435 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1461 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: 0033:0x7f140b98d510 RSP: 002b:00007f140c750ef0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f140b98d510 RDX: 0000000000000002 RSI: 00007f140ba11af4 RDI: 00000000ffffff9c RBP: 00007f140ba11af4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000024 R14: 0000200000000000 R15: 00007fff80fda8e8 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e53c560 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e53c560 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e53c560 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5620: #0: ffff88814caf10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036be2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 1 lock held by udevd/5870: #0: ffff888025a8e358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945 1 lock held by udevd/6851: #0: ffff888025a8c358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945 6 locks held by syz.3.447/7186: #0: ffff888031a96478 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320 fs/file.c:1232 #1: ffff88807de76420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3108 [inline] #1: ffff88807de76420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x211/0xb30 fs/read_write.c:682 #2: ffff88803433f088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #3: ffff888140eacb48 (kn->active#65){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #3: ffff888140eacb48 (kn->active#65){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #4: ffffffff8e3ec328 (system_transition_mutex){+.+.}-{4:4}, at: software_resume+0x47/0x420 kernel/power/hibernate.c:1038 #5: ffff888025a8e358 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xe0/0xd30 block/bdev.c:945 2 locks held by syz.1.452/7205: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 #1: ffffffff8e3ec328 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x4a/0x70 kernel/power/main.c:57 1 lock held by syz.2.453/7208: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz.0.455/7214: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz-executor/7216: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz-executor/7219: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz-executor/7220: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz-executor/7222: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 4 locks held by kworker/0:6/7229: 1 lock held by syz-executor/7231: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz-executor/7234: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz-executor/7235: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz-executor/7237: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz-executor/7245: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz-executor/7248: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz-executor/7249: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 1 lock held by syz-executor/7251: #0: ffffffff8edd7f48 (misc_mtx){+.+.}-{4:4}, at: misc_open+0x51/0x350 drivers/char/misc.c:125 ============================================= 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 07/12/2025 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:332 [inline] watchdog+0xf60/0xfa0 kernel/hung_task.c:495 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x47c/0x820 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: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:-1 [inline] RIP: 0010:rcu_is_watching+0x1c/0xb0 kernel/rcu/tree.c:751 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 65 ff 05 50 57 40 11 e8 2b d2 e3 09 89 c3 83 f8 08 73 65 <49> bf 00 00 00 00 00 fc ff df 4c 8d 34 dd d0 8d ec 8d 4c 89 f0 48 RSP: 0018:ffffc90000146de0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 8c20b3c5c19a4c00 RDX: 0000000000000100 RSI: ffffffff8c04efe0 RDI: ffffffff8c04efa0 RBP: ffff88807c2ca208 R08: ffff88807c2ca223 R09: 1ffff1100f859444 R10: dffffc0000000000 R11: ffffed100f859445 R12: ffff88807c2ca202 R13: 1ffff11008491ee1 R14: ffff888140eaeb40 R15: ffffffff89695b7d FS: 0000000000000000(0000) GS:ffff8881257b1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6bda138060 CR3: 000000007e884000 CR4: 00000000003526f0 Call Trace: trace_kmem_cache_free include/trace/events/kmem.h:117 [inline] kmem_cache_free+0x5e/0x690 mm/slub.c:6231 skb_release_data+0x62d/0x7c0 net/core/skbuff.c:1086 skb_release_all net/core/skbuff.c:1151 [inline] __kfree_skb net/core/skbuff.c:1165 [inline] consume_skb+0x9e/0xf0 net/core/skbuff.c:1397 nft_synproxy_eval_v4+0x376/0x560 net/netfilter/nft_synproxy.c:60 nft_synproxy_do_eval+0x345/0x570 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x40c/0x1920 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x25d/0x340 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6040 [inline] __netif_receive_skb+0x143/0x380 net/core/dev.c:6153 process_backlog+0x60e/0x14f0 net/core/dev.c:6505 __napi_poll+0xc4/0x360 net/core/dev.c:7555 napi_poll net/core/dev.c:7618 [inline] net_rx_action+0x707/0xe30 net/core/dev.c:7745 handle_softirqs+0x286/0x870 kernel/softirq.c:579 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968 smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x47c/0x820 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 IPVS: fo: UDP 224.0.0.2:0 - no destination available