INFO: task syz.2.648:9039 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.648 state:D stack:26504 pid:9039 tgid:9036 ppid:5649 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5583 [inline]
__schedule+0x17dd/0x5830 kernel/sched/core.c:7382
__schedule_loop kernel/sched/core.c:7459 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7474
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7531
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7c4/0x15a0 kernel/locking/mutex.c:821
sync_bdevs+0x294/0x480 block/bdev.c:1378
ksys_sync fs/sync.c:105 [inline]
__ia32_sys_sync+0xc5/0x120 fs/sync.c:111
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe7ce59f559
RSP: 002b:00007fe7cf3a3028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007fe7ce826090 RCX: 00007fe7ce59f559
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fe7ce826090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe7ce826128 R14: 00007fe7ce826090 R15: 00007ffea8ee4bc8
Showing all locks held in the system:
locks held by kworker/u8:0/13: 5, last CPU#0:
#0: ffff88813fe4c148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813fe4c148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813fe4c148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff88813fe4c148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffff8880b8224708 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x57/0x7d0 kernel/sched/psi.c:928
#2: ffffffff9c13a080 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0xb7/0x420 lib/debugobjects.c:873
#3: ffff88807e90cf90 (&bat_priv->forw_bat_list_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:353 [inline]
#3: ffff88807e90cf90 (&bat_priv->forw_bat_list_lock){+...}-{3:3}, at: batadv_forw_packet_queue+0x33/0x240 net/batman-adv/send.c:665
#4: ffff8880b8226498 (&base->lock){-.-.}-{2:2}, at: lock_timer_base kernel/time/timer.c:1005 [inline]
#4: ffff8880b8226498 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x1a9/0xed0 kernel/time/timer.c:1086
locks held by pr/ttyS0/34: 2, last CPU#1:
#0: ffffffff90033f18 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:314 [inline]
#0: ffffffff90033f18 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:493 [inline]
#0: ffffffff90033f18 (console_srcu){....}-{0:0}, at: console_srcu_read_lock+0x30/0x60 kernel/printk/printk.c:291
#1: ffffffff9c203ef8 (&port_lock_key){-.-.}-{3:3}, at: __uart_port_lock_irqsave include/linux/serial_core.h:613 [inline]
#1: ffffffff9c203ef8 (&port_lock_key){-.-.}-{3:3}, at: univ8250_console_device_lock+0x67/0xc0 drivers/tty/serial/8250/8250_core.c:413
locks held by khungtaskd/35: 1, last CPU#0:
#0: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/0:2/54: 2, on CPU#0:
#0: ffff88813fe0ed48 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813fe0ed48 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813fe0ed48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff88813fe0ed48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc90000be7c40 (free_ipc_work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90000be7c40 (free_ipc_work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90000be7c40 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc90000be7c40 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
locks held by syslogd/4985: 1, last CPU#1:
#0: ffff888037303078 (&u->iolock){+.+.}-{4:4}, at: __unix_dgram_recvmsg+0x1f2/0xe60 net/unix/af_unix.c:2591
locks held by getty/5394: 2, on CPU#0:
#0: ffff888034d2a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000323b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by syz-executor/5624: 3, on CPU#0:
#0: ffff88807bbd8308 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:339
#1: ffff8880372b8570 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline]
#1: ffff8880372b8570 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x1fe/0x1470 fs/ext4/inode.c:7863
#2: ffff8880372de950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x1fb0/0x21f0 fs/jbd2/transaction.c:444
locks held by syz-executor/8827: 1, last CPU#1:
#0: ffffffff90160aa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#0: ffffffff90160aa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2cb/0x760 kernel/rcu/tree_exp.h:966
locks held by udevd/8836: 1, on CPU#0:
#0: ffff888026e98350 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0xde/0xd70 block/bdev.c:990
locks held by syz.2.648/9039: 1, on CPU#1:
#0: ffff888026e98350 (&disk->open_mutex){+.+.}-{4:4}, at: sync_bdevs+0x294/0x480 block/bdev.c:1378
locks held by syz.6.873/10134: 5, last CPU#0:
#0: ffffffff9c253168 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:164 [inline]
#0: ffffffff9c253168 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
#0: ffffffff9c253168 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv+0x33d/0xa40 drivers/infiniband/core/netlink.c:259
#1: ffffffff913f5108 (link_ops_rwsem){++++}-{4:4}, at: nldev_newlink+0x42b/0x650 drivers/infiniband/core/nldev.c:1849
#2: ffffffff913e6228 (devices_rwsem){++++}-{4:4}, at: enable_device_and_get+0xff/0x3e0 drivers/infiniband/core/device.c:1365
#3: ffffffff913e6528 (clients_rwsem){++++}-{4:4}, at: enable_device_and_get+0x165/0x3e0 drivers/infiniband/core/device.c:1373
#4: ffff88806a154658 (&device->client_data_rwsem){++++}-{4:4}, at: add_client_context+0x33e/0x7b0 drivers/infiniband/core/device.c:753
locks held by syz.4.875/10117: 1, on CPU#0:
#0: ffffffff90160978 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x175/0x610 kernel/rcu/tree.c:4002
locks held by syz.8.877/10127: 2, on CPU#1:
#0: ffff8880558070e0 (&nft_net->commit_mutex){+.+.}-{4:4}, at: nf_tables_valid_genid+0x3e/0x100 net/netfilter/nf_tables_api.c:11574
#1: ffffffff90160aa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#1: ffffffff90160aa8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x388/0x760 kernel/rcu/tree_exp.h:966
locks held by syz.6.873/10135: 3, last CPU#0:
#0: ffff88807f57c478 (sb_writers#5){.+.+}-{0:0}, at: vfs_coredump+0xac3/0x10c0 fs/coredump.c:1312
#1: ffff88803ae12d30 (&sb->s_type->i_mutex_key#15){++++}-{4:4}, at: inode_lock include/linux/fs.h:1026 [inline]
#1: ffff88803ae12d30 (&sb->s_type->i_mutex_key#15){++++}-{4:4}, at: shmem_file_write_iter+0x7f/0x120 mm/shmem.c:3674
#2: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#2: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#2: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#2: ffffffff9015a420 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [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:377 [inline]
watchdog+0x1073/0x10f0 kernel/hung_task.c:598
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 34 Comm: pr/ttyS0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:preempt_count_add+0x0/0x140 kernel/sched/core.c:6043
Code: be e0 0e 00 00 e8 a0 7e aa 00 e9 70 ff ff ff e9 d3 fe ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 41 56 53 49 bf 00 00 00 00 00 fc ff df 48 63 c7
RSP: 0018:ffffc90000aa78b0 EFLAGS: 00000807
RAX: 000000002e45d660 RBX: 0000000000000899 RCX: 00000000068e9788
RDX: 0000000000000898 RSI: 00000000000007e3 RDI: 0000000000000001
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff8c035f90 R12: 1ffffffff3840839
R13: 00000000ffffffff R14: ffffffff9c203ee0 R15: 00000000000007e2
FS: 0000000000000000(0000) GS:ffff88812350b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ec4a25fac CR3: 000000007f8b6000 CR4: 00000000003526f0
Call Trace:
delay_tsc+0x17/0xd0 arch/x86/lib/delay.c:66
udelay include/asm-generic/delay.h:62 [inline]
wait_for_lsr+0x147/0x2f0 drivers/tty/serial/8250/8250_port.c:2042
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3294 [inline]
__serial8250_console_fifo_write+0xcd/0x3e0 drivers/tty/serial/8250/8250_port.c:3369
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3402 [inline]
__serial8250_console_write drivers/tty/serial/8250/8250_port.c:3456 [inline]
serial8250_console_write+0xa7e/0x1200 drivers/tty/serial/8250/8250_port.c:3520
nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1
nbcon_emit_one kernel/printk/nbcon.c:1157 [inline]
nbcon_kthread_func+0x6d9/0x8d0 kernel/printk/nbcon.c:1271
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245