INFO: task syz.7.4263:22280 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.7.4263 state:D stack:28520 pid:22280 tgid:22277 ppid:6642 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821
nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
nfsd_umount+0x41/0x60 fs/nfsd/nfsctl.c:1365
deactivate_locked_super+0xbc/0x130 fs/super.c:477
cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x1fa/0x730 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:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc59ff9de59
RSP: 002b:00007fc59e1b4028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: fffffffffffffffe RBX: 00007fc5a0226180 RCX: 00007fc59ff9de59
RDX: 00002000000000c0 RSI: 0000200000000080 RDI: 0000000000000000
RBP: 00007fc5a0033e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000010 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc5a0226218 R14: 00007fc5a0226180 R15: 00007ffd1b801238
INFO: task syz.5.4264:22287 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.5.4264 state:D stack:27616 pid:22287 tgid:22283 ppid:11711 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821
nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
nfsd_umount+0x41/0x60 fs/nfsd/nfsctl.c:1365
deactivate_locked_super+0xbc/0x130 fs/super.c:477
cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x1fa/0x730 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:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb4d859de59
RSP: 002b:00007fb4d9407028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: fffffffffffffffe RBX: 00007fb4d8826180 RCX: 00007fb4d859de59
RDX: 00002000000000c0 RSI: 0000200000000080 RDI: 0000000000000000
RBP: 00007fb4d8633e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000010 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb4d8826218 R14: 00007fb4d8826180 R15: 00007ffcba5b7e08
INFO: task syz.8.4277:22333 blocked for more than 144 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.4277 state:D stack:27616 pid:22333 tgid:22328 ppid:7748 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821
nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
nfsd_umount+0x41/0x60 fs/nfsd/nfsctl.c:1365
deactivate_locked_super+0xbc/0x130 fs/super.c:477
cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x1fa/0x730 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:318 [inline]
do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f380799de59
RSP: 002b:00007f38087c7028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: fffffffffffffffe RBX: 00007f3807c26180 RCX: 00007f380799de59
RDX: 00002000000000c0 RSI: 0000200000000080 RDI: 0000000000000000
RBP: 00007f3807a33e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000010 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3807c26218 R14: 00007f3807c26180 R15: 00007ffc9188bbe8
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8eb59c60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5375:
#0: ffff888035ce00a0 (&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
2 locks held by syz.3.4252/22247:
#0: ffffffff9009cd28 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8ee8e5e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2b9/0xc30 fs/nfsd/nfsctl.c:1660
2 locks held by syz.7.4263/22280:
#0: ffff8880282fa0d8 (&type->s_umount_key
#125
){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:509
#1: ffffffff8ee8e5e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
2 locks held by syz.5.4264/22287:
#0: ffff88807bc960d8 (&type->s_umount_key#125){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807bc960d8 (&type->s_umount_key#125){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807bc960d8 (&type->s_umount_key#125){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:509
#1: ffffffff8ee8e5e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
2 locks held by syz.8.4277/22333:
#0: ffff8880733120d8 (&type->s_umount_key#125){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880733120d8 (&type->s_umount_key#125){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880733120d8 (&type->s_umount_key#125){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:509
#1: ffffffff8ee8e5e0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:576
2 locks held by syz.6.4575/24136:
#0: ffff8880630aa260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
#0: ffff8880630aa260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_setsockopt+0x5a0/0x1510 net/packet/af_packet.c:3825
#1: ffffffff8eb5ff68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#1: ffffffff8eb5ff68 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
3 locks held by syz.2.4576/24142:
1 lock held by dhcpcd/24143:
#0: ffff88807752d880 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
#0: ffff88807752d880 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release net/socket.c:709 [inline]
#0: ffff88807752d880 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: sock_close+0x82/0x220 net/socket.c:1501
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
trigger_all_cpu_backtrace include/linux/nmi.h:162 [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:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 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 1 to CPUs 0:
EXT4-fs (loop2): initial error at time 1783857359: ext4_mb_generate_buddy:1317
EXT4-fs (loop2): last error at time 1783857359: ext4_mb_generate_buddy:1317
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 24142 Comm: syz.2.4576 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026
RIP: 0010:check_prev_add kernel/locking/lockdep.c:-1 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3908 [inline]
RIP: 0010:__lock_acquire+0x206e/0x2cf0 kernel/locking/lockdep.c:5237
Code: 10 4c 8b 6c 24 08 48 8b 34 24 48 83 c3 30 eb 17 48 69 c0 c8 00 00 00 48 8d 80 10 45 15 94 49 39 c7 0f 84 10 02 00 00 48 8b 1b <41> 8b 45 20 25 ff 1f 00 00 48 0f a3 05 81 fd d1 12 73 10 48 69 c0
RSP: 0018:ffffc9000541e6a8 EFLAGS: 00000097
RAX: ffffffff9419b2a8 RBX: ffffffff96ff7d58 RCX: 0000000000000003
RDX: 0000000000030000 RSI: ffff888035e32b18 RDI: 0000000000000000
RBP: 306a0f34b6b1b451 R08: ffffc9000541e670 R09: 0000000000000020
R10: 0000000000000000 R11: ffffffff81a29270 R12: 00000000000000c5
R13: ffff888035e32b68 R14: ffff888035e31f00 R15: ffffffff9418c2d0
FS: 00007f0ecbdf66c0(0000) GS:ffff888124f58000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f4bb28f168 CR3: 0000000021abb000 CR4: 0000000000350ef0
Call Trace:
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
__raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158
console_lock_spinning_enable kernel/printk/printk.c:1896 [inline]
console_emit_next_record kernel/printk/printk.c:3177 [inline]
console_flush_one_record kernel/printk/printk.c:3269 [inline]
console_flush_all+0x651/0xaf0 kernel/printk/printk.c:3343
__console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413
vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479
_printk+0xdd/0x130 kernel/printk/printk.c:2504
__ext4_msg+0x2b9/0x2d0 fs/ext4/super.c:1001
ext4_handle_error+0x743/0x940 fs/ext4/super.c:741
__ext4_grp_locked_error+0x2e9/0xc60 fs/ext4/super.c:1090
ext4_mb_generate_buddy+0x2dc/0x450 fs/ext4/mballoc.c:1314
ext4_mb_init_cache+0xee0/0x1650 fs/ext4/mballoc.c:1499
ext4_mb_init_group+0x77a/0xb20 fs/ext4/mballoc.c:1657
ext4_mb_load_buddy_gfp+0x1156/0x1560 fs/ext4/mballoc.c:1705
ext4_mb_clear_bb fs/ext4/mballoc.c:6580 [inline]
ext4_free_blocks+0xb5f/0x1c10 fs/ext4/mballoc.c:6782
ext4_remove_blocks fs/ext4/extents.c:2569 [inline]
ext4_ext_rm_leaf fs/ext4/extents.c:2734 [inline]
ext4_ext_remove_space+0x1d2b/0x4230 fs/ext4/extents.c:2979
ext4_ext_truncate+0x17e/0x2f0 fs/ext4/extents.c:4566
ext4_truncate+0x917/0x1090 fs/ext4/inode.c:4668
ext4_process_orphan+0x1a9/0x2e0 fs/ext4/orphan.c:337
ext4_orphan_cleanup+0xc7a/0x14c0 fs/ext4/orphan.c:472
__ext4_fill_super fs/ext4/super.c:5705 [inline]
ext4_fill_super+0x5cb4/0x65c0 fs/ext4/super.c:5828
get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1634
vfs_get_tree+0x92/0x2a0 fs/super.c:1694
fc_mount fs/namespace.c:1198 [inline]
do_new_mount_fc fs/namespace.c:3765 [inline]
do_new_mount+0x319/0xdc0 fs/namespace.c:3841
do_mount fs/namespace.c:4174 [inline]
__do_sys_mount fs/namespace.c:4390 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4367
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0ecdb9f0ca
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0ecbdf5e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f0ecbdf5ee0 RCX: 00007f0ecdb9f0ca
RDX: 0000200000000100 RSI: 0000200000000080 RDI: 00007f0ecbdf5ea0
RBP: 0000200000000100 R08: 00007f0ecbdf5ee0 R09: 0000000003000010
R10: 0000000003000010 R11: 0000000000000246 R12: 0000200000000080
R13: 00007f0ecbdf5ea0 R14: 000000000000051a R15: 000000000000002c