INFO: task syz.8.1852:14425 blocked in I/O wait for
INFO: task syz.8.1852:14425 blocked in I/O wait for more than 143 seconds.
Tainted: G L syzkaller #0
Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.1852 state:D stack:25368 pid:14425 tgid:14423 ppid:6892 task_flags:0x40054c flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5581 [inline]
__schedule+0x1b47/0x5b40 kernel/sched/core.c:7384
__schedule_loop kernel/sched/core.c:7461 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7476
io_schedule+0x7f/0xd0 kernel/sched/core.c:8148
folio_wait_bit_common+0x85e/0xc40 mm/filemap.c:1328
folio_wait_writeback+0xb0/0x100 mm/page-writeback.c:3062
__filemap_fdatawait_range+0x184/0x2a0 mm/filemap.c:532
filemap_write_and_wait_range+0x276/0x3f0 mm/filemap.c:692
filemap_write_and_wait include/linux/pagemap.h:64 [inline]
sync_blockdev block/bdev.c:275 [inline]
bdev_release+0x1a0/0x690 block/bdev.c:1171
blkdev_release+0x15/0x20 block/fops.c:704
__fput+0x413/0xa50 fs/file_table.c:513
task_work_run+0x1d9/0x260 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x705/0x2380 kernel/exit.c:980
do_group_exit+0x22d/0x2f0 kernel/exit.c:1123
get_signal+0x1216/0x12c0 kernel/signal.c:3112
arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f537699e159
RSP: 002b:00007f537790d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f5376c25fa8 RCX: 00007f537699e159
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f5376c25fa8
RBP: 00007f5376c25fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5376c26038 R14: 00007ffdae9c8e60 R15: 00007ffdae9c8f48
Showing all locks held in the system:
locks held by khungtaskd/34: 1, last CPU#0:
#0: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by getty/5365: 2, on CPU#1:
#0: ffff888035dd50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by syz-executor/6894: 1, last CPU#0:
#0: ffff88803243e420 (&xt[i].mutex){+.+.}-{4:4}, at: xt_find_table_lock+0x55/0x400 net/netfilter/x_tables.c:1336
locks held by syz.0.1931/14797: 2, on CPU#0:
#0: ffff8880238bfae8 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#0: ffff8880238bfae8 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: blk_ioctl_zeroout block/ioctl.c:238 [inline]
#0: ffff8880238bfae8 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at: blkdev_common_ioctl+0x22a9/0x3250 block/ioctl.c:667
#1: ffff8880238bfc80 (mapping.invalidate_lock){++++}-{4:4}, at: filemap_invalidate_lock include/linux/fs.h:1079 [inline]
#1: ffff8880238bfc80 (mapping.invalidate_lock){++++}-{4:4}, at: blk_ioctl_zeroout block/ioctl.c:239 [inline]
#1: ffff8880238bfc80 (mapping.invalidate_lock){++++}-{4:4}, at: blkdev_common_ioctl+0x22d7/0x3250 block/ioctl.c:667
locks held by syz-executor/15308: 4, last CPU#1:
#0: ffffffff8ee362f0 (dup_mmap_sem){++++}-{0:0}, at: dup_mm kernel/fork.c:1541 [inline]
#0: ffffffff8ee362f0 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x10a/0x470 kernel/fork.c:1594
#1: ffff88807f486540 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:548 [inline]
#1: ffff88807f486540 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x195/0x1dc0 mm/mmap.c:1716
#2: ffff88807dff0f80 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:538 [inline]
#2: ffff88807dff0f80 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x221/0x1dc0 mm/mmap.c:1723
#3: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#3: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:302
locks held by kworker/u8:27/15326: 3, on CPU#1:
#0: ffff8880323d7948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff8880323d7948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff8880323d7948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#0: ffff8880323d7948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#1: ffffc9000675fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000675fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000675fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
#1: ffffc9000675fc40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
#2: ffffffff902550a0 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#2: ffffffff902550a0 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x116/0x15c0 net/ipv6/addrconf.c:4235
locks held by syz-executor/15782: 3, on CPU#1:
#0: ffffffff902b94e8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff902b9320 (genl_mutex){+.+.}-{4:4}, at: genl_lock net/netlink/genetlink.c:35 [inline]
#1: ffffffff902b9320 (genl_mutex){+.+.}-{4:4}, at: genl_op_lock net/netlink/genetlink.c:60 [inline]
#1: ffffffff902b9320 (genl_mutex){+.+.}-{4:4}, at: genl_rcv_msg+0x10b/0x7a0 net/netlink/genetlink.c:1208
#2: ffffffff902550a0 (rtnl_mutex){+.+.}-{4:4}, at: ieee80211_register_hw+0x38bb/0x4b40 net/mac80211/main.c:1565
locks held by udevd/15937: 1, on CPU#1:
#0: ffff88801c2dca10 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: kernfs_iop_permission+0x7f/0x430 fs/kernfs/inode.c:286
locks held by syz-executor/16040: 10, last CPU#0:
#0: ffff888035ae8460 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#0: ffff888035ae8460 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22b/0xba0 fs/read_write.c:683
#1: ffff88807eca5880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d8/0x540 fs/kernfs/file.c:336
#2: ffff888029c20c38 (kn->active#51){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#2: ffff888029c20c38 (kn->active#51){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22b/0x540 fs/kernfs/file.c:337
#3: ffffffff8fad2f40 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:233
#4: ffff88802b273128 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#4: ffff88802b273128 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
#4: ffff88802b273128 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880 drivers/base/dd.c:1369
#5: ffff88802b276258 (&devlink->lock_key#16){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x170 drivers/net/netdevsim/dev.c:1724
#6: ffffffff902550a0 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x173/0x800 drivers/net/netdevsim/netdev.c:1201
#7: ffff88801c2dcaa0 (&root->kernfs_supers_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x3f/0x140 fs/kernfs/dir.c:1790
#8: ffff88801c2dc980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x4e/0x140 fs/kernfs/dir.c:1791
#9: ffff88801c2dca10 (&root->kernfs_iattr_rwsem){++++}-{4:4}, at: kernfs_unlink_sibling+0x6d/0x240 fs/kernfs/dir.c:443
locks held by sed/16308: 1, last CPU#0:
#0: ffff88807dfa2bc8 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1d1/0x500 mm/mmap_lock.c:309
locks held by syz.3.2192/16310: 4, last CPU#1:
#0: ffff88807dff4cc0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:586 [inline]
#0: ffff88807dff4cc0 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1299
#1: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:302
#2: ffff8880599ddcd8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:347 [inline]
#2: ffff8880599ddcd8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:423
#3: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#3: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff8ed5a3a0 (rcu_read_lock){....}-{1:3}, at: page_table_check_clear+0x1d0/0x590 mm/page_table_check.c:77
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
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+0x1058/0x10d0 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: 16 Comm: pr/ttyS0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:io_serial_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:432
Code: 3c 4f fc 44 89 f9 d3 e5 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 2c 14 c1 fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d e9 97 54 75 06 cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90000157900 EFLAGS: 00000002
RAX: 000000000000005b RBX: 000000000000005b RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000020
RBP: 00000000000003f8 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff85794480 R12: dffffc0000000000
R13: 000000000000005b R14: ffffffff9ad50fc0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888124dbd000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c256396 CR3: 00000000778ca000 CR4: 00000000003526f0
Call Trace:
serial_port_out include/linux/serial_core.h:817 [inline]
serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3311 [inline]
__serial8250_console_fifo_write+0x1e6/0x3e0 drivers/tty/serial/8250/8250_port.c:3383
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