INFO: task syz-executor:4193 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:21840 pid: 4193 ppid: 1 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
wb_wait_for_completion+0x171/0x290 fs/fs-writeback.c:191
sync_inodes_sb+0x1bd/0x950 fs/fs-writeback.c:2787
sync_filesystem+0x16d/0x220 fs/sync.c:64
generic_shutdown_super+0x6b/0x300 fs/super.c:448
kill_block_super+0x7c/0xe0 fs/super.c:1427
deactivate_locked_super+0x93/0xf0 fs/super.c:335
cleanup_mnt+0x42d/0x4e0 fs/namespace.c:1148
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f59ea19c9d7
RSP: 002b:00007ffe3e6c2408 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f59ea230f90 RCX: 00007f59ea19c9d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe3e6c24c0
RBP: 00007ffe3e6c24c0 R08: 00007ffe3e6c34c0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe3e6c3550
R13: 00007f59ea230f90 R14: 000000000002bd3d R15: 00007ffe3e6c3590
Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/u4:3/375:
2 locks held by dhcpcd/3852:
#0:
ffffffff8d424cc8
(
vlan_ioctl_mutex
){+.+.}-{3:3}
, at: sock_ioctl+0x25a/0x710 net/socket.c:1228
#1:
ffffffff8d43c848
(
rtnl_mutex
){+.+.}-{3:3}
, at: vlan_ioctl_handler+0xef/0x5d0 net/8021q/vlan.c:581
2 locks held by getty/3953:
#0: ffff88802c3c5098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc900026562e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
2 locks held by syz-executor/4184:
#0: ffff88807c9860e0 (&type->s_umount_key#63){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
#1: ffff888147a0c7d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
#1: ffff888147a0c7d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1a1/0x950 fs/fs-writeback.c:2785
2 locks held by syz-executor/4185:
#0: ffff8881480720e0 (&type->s_umount_key#63){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
#1: ffff888020c487d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
#1: ffff888020c487d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1a1/0x950 fs/fs-writeback.c:2785
2 locks held by syz-executor/4193:
#0: ffff888020b1d918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
#1: ffff888020c42468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xaa/0xb90 drivers/block/loop.c:1366
2 locks held by syz-executor/4197:
#0: ffff888077cee0e0 (&type->s_umount_key#63){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:365
#1: ffff888020cc47d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
#1: ffff888020cc47d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1a1/0x950 fs/fs-writeback.c:2785
2 locks held by kworker/1:5/4224:
3 locks held by kworker/1:7/4227:
#0:
ffff88802b3c7938
(
(wq_completion)ipv6_addrconf
){+.+.}-{0:0}
, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1:
ffffc900031bfd00
(
(work_completion)(&(&ifa->dad_work)->work)
){+.+.}-{0:0}
, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2:
ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xca/0x1540 net/ipv6/addrconf.c:4110
7 locks held by kworker/u4:6/4235:
4 locks held by kworker/u4:9/5109:
3 locks held by kworker/u4:11/5115:
#0: ffff888016c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc900033b7d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2:
ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
7 locks held by kworker/u4:16/5131:
2 locks held by kworker/0:20/6924:
#0:
ffff888016c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc900033c7d00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
3 locks held by kworker/0:23/8043:
#0: ffff88802b3c7938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc90002e2fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xca/0x1540 net/ipv6/addrconf.c:4110
1 lock held by syz-executor/9918:
#0: ffffffff8d43c848
(
rtnl_mutex
){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5681
2 locks held by syz.1.1651/10281:
#0: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:699 [inline]
#0: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3440
#1: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
#1: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
1 lock held by syz.9.1659/10310:
#0:
ffffffff8d43c848
(rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
(rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5681
1 lock held by syz.9.1659/10311:
#0: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffffffff8d43c848 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5681
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xe0f/0xe50 kernel/hung_task.c:369
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4193 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:uncharge_batch+0x371/0x420 mm/memcontrol.c:6894
Code: 89 fa 80 e2 07 80 c2 03 38 c2 0f 8c aa fd ff ff 4c 89 ff 48 89 cb e8 3e 17 fb ff 48 89 d9 e9 97 fd ff ff 80 3d e8 fc 1f 0a 00 <0f> 85 52 fd ff ff 42 80 3c 23 00 74 08 4c 89 ef e8 2a 17 fb ff 41
RSP: 0018:ffffc90002f6f500 EFLAGS: 00000246
RAX: ffffffff81c25867 RBX: 1ffff920005edec5 RCX: ffff88807c660000
RDX: 0000000000000000 RSI: 000000000000525b RDI: ffff888016e7c120
RBP: ffffc90002f6f5d0 R08: ffff888016e7c127 R09: 1ffff11002dcf824
R10: dffffc0000000000 R11: ffffed1002dcf825 R12: dffffc0000000000
R13: ffffc90002f6f628 R14: 1ffff920005edec6 R15: 0000000000000004
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055915637ff28 CR3: 000000000c08e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
uncharge_page+0x185/0x490 mm/memcontrol.c:6941
__mem_cgroup_uncharge_list+0x6c/0xc0 mm/memcontrol.c:7004
mem_cgroup_uncharge_list include/linux/memcontrol.h:720 [inline]
release_pages+0x1864/0x1be0 mm/swap.c:962
tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
tlb_flush_mmu mm/mmu_gather.c:247 [inline]
tlb_finish_mmu+0x176/0x300 mm/mmu_gather.c:338
exit_mmap+0x3d0/0x640 mm/mmap.c:3218
__mmput+0x115/0x3b0 kernel/fork.c:1127
exit_mm+0x588/0x6e0 kernel/exit.c:550
do_exit+0x5a9/0x20c0 kernel/exit.c:870
do_group_exit+0x12e/0x300 kernel/exit.c:997
get_signal+0x6ca/0x12c0 kernel/signal.c:2900
arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f59ea19c9d7
Code: Unable to access opcode bytes at RIP 0x7f59ea19c9ad.
RSP: 002b:00007ffe3e6c2408 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f59ea230f90 RCX: 00007f59ea19c9d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe3e6c24c0
RBP: 00007ffe3e6c24c0 R08: 00007ffe3e6c34c0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe3e6c3550
R13: 00007f59ea230f90 R14: 000000000002bd3d R15: 00007ffe3e6c3590