INFO: task syz.0.16:6558 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.16 state:D stack:28264 pid:6558 tgid:6556 ppid:6286 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 inode_lock include/linux/fs.h:870 [inline] blkdev_fallocate+0x263/0x550 block/fops.c:904 vfs_fallocate+0x66f/0x7f0 fs/open.c:342 ksys_fallocate fs/open.c:366 [inline] __do_sys_fallocate fs/open.c:371 [inline] __se_sys_fallocate fs/open.c:369 [inline] __x64_sys_fallocate+0xc0/0x110 fs/open.c:369 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb067605d29 RSP: 002b:00007fb066876038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 00007fb0677f5fa0 RCX: 00007fb067605d29 RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000004 RBP: 00007fb067681b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000100001002000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb0677f5fa0 R15: 00007ffff8268d48 INFO: task syz.2.18:6559 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.18 state:D stack:28264 pid:6559 tgid:6557 ppid:6293 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 inode_lock include/linux/fs.h:870 [inline] blkdev_fallocate+0x263/0x550 block/fops.c:904 vfs_fallocate+0x66f/0x7f0 fs/open.c:342 ksys_fallocate fs/open.c:366 [inline] __do_sys_fallocate fs/open.c:371 [inline] __se_sys_fallocate fs/open.c:369 [inline] __x64_sys_fallocate+0xc0/0x110 fs/open.c:369 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1cae985d29 RSP: 002b:00007f1cadbfe038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 00007f1caeb75fa0 RCX: 00007f1cae985d29 RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000004 RBP: 00007f1caea01b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000100001002000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f1caeb75fa0 R15: 00007ffc4480d628 INFO: task syz.3.19:6568 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.19 state:D stack:26920 pid:6568 tgid:6567 ppid:6296 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 inode_lock include/linux/fs.h:870 [inline] blkdev_fallocate+0x263/0x550 block/fops.c:904 vfs_fallocate+0x66f/0x7f0 fs/open.c:342 ksys_fallocate fs/open.c:366 [inline] __do_sys_fallocate fs/open.c:371 [inline] __se_sys_fallocate fs/open.c:369 [inline] __x64_sys_fallocate+0xc0/0x110 fs/open.c:369 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f05a3025d29 RSP: 002b:00007f05a2296038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 00007f05a3215fa0 RCX: 00007f05a3025d29 RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000004 RBP: 00007f05a30a1b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000100001002000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f05a3215fa0 R15: 00007ffcb41e9198 INFO: task syz.4.20:6574 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.20 state:D stack:28264 pid:6574 tgid:6573 ppid:6299 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 inode_lock include/linux/fs.h:870 [inline] blkdev_fallocate+0x263/0x550 block/fops.c:904 vfs_fallocate+0x66f/0x7f0 fs/open.c:342 ksys_fallocate fs/open.c:366 [inline] __do_sys_fallocate fs/open.c:371 [inline] __se_sys_fallocate fs/open.c:369 [inline] __x64_sys_fallocate+0xc0/0x110 fs/open.c:369 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f42805f5d29 RSP: 002b:00007f427f866038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d RAX: ffffffffffffffda RBX: 00007f42807e5fa0 RCX: 00007f42805f5d29 RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000004 RBP: 00007f4280671b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000100001002000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f42807e5fa0 R15: 00007ffc4b0b8ed8 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:12/1500: #0: ffff8880301be938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff8880301be938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90005ccfbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90005ccfbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x119/0x15a0 net/ipv6/addrconf.c:4194 3 locks held by kworker/u8:15/3551: #0: ffff888019881138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff888019881138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000de37bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000de37bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 6 locks held by kworker/u8:18/3656: 2 locks held by getty/5603: #0: ffff88823bf2c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222 2 locks held by syz.1.17/6537: 1 lock held by syz.0.16/6558: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.2.18/6559: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.3.19/6568: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.4.20/6574: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.5.21/6796: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.6.22/6801: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.7.23/6800: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.9.25/6804: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.8.24/6806: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.1.26/6873: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.3.29/6923: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.0.27/6925: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.2.28/6927: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.4.30/6929: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.5.31/6970: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.6.32/7077: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.7.33/7096: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.8.34/7098: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.1.36/7100: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz.9.35/7102: #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline] #0: ffff8880223f3ba8 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:904 1 lock held by syz-executor/7113: #0: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4056 2 locks held by syz-executor/7125: #0: ffffffff8f1d7f08 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8f1d7f08 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8f1d7f08 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4056 3 locks held by syz-executor/7133: 2 locks held by syz-executor/7134: #0: ffffffff8e43b9e0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e43b9e0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e43b9e0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4056 2 locks held by syz-executor/7135: #0: ffffffff8e43b9e0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e43b9e0 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e43b9e0 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8ecd3938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4056 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 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:328 [inline] watchdog+0xf93/0xfe0 kernel/hung_task.c:491 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 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: 3656 Comm: kworker/u8:18 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:check_preemption_disabled+0x0/0x120 lib/smp_processor_id.c:13 Code: c7 20 16 62 8b 48 c7 c6 60 16 62 8b eb 1c 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <55> 41 57 41 56 53 48 83 ec 10 65 48 8b 05 fe 14 ff 06 48 89 44 24 RSP: 0018:ffffc9000e567710 EFLAGS: 00000006 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 66e41c81d71f4200 RDX: 0000000000000200 RSI: ffffffff8d04e087 RDI: ffffffff8b621680 RBP: ffffc9000e567850 R08: ffffffff8f1d6337 R09: 1ffffffff1e3ac66 R10: dffffc0000000000 R11: fffffbfff1e3ac67 R12: ffff888031a60b0c R13: ffffffff8184e26c R14: ffffffff8d9a8d80 R15: ffff888031a60000 FS: 0000000000000000(0000) GS:ffff8881268bc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056195f421a38 CR3: 000000000d7a6000 CR4: 00000000003526f0 Call Trace: lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline] lock_release+0xbc/0x3e0 kernel/locking/lockdep.c:5888 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] __local_bh_enable+0x1f8/0x3d0 kernel/softirq.c:213 __local_bh_enable_ip+0x1a4/0x270 kernel/softirq.c:262 local_bh_enable include/linux/bottom_half.h:33 [inline] spin_unlock_bh include/linux/spinlock_rt.h:111 [inline] batadv_nc_purge_paths+0x34d/0x3f0 net/batman-adv/network-coding.c:471 batadv_nc_worker+0x87e/0xbc0 net/batman-adv/network-coding.c:720 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245