INFO: task kworker/u4:2:151 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:2 state:D stack:24416 pid: 151 ppid: 2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:4)
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
__mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:108
jfs_write_inode+0x141/0x220 fs/jfs/inode.c:138
write_inode fs/fs-writeback.c:1505 [inline]
__writeback_single_inode+0x6c3/0xda0 fs/fs-writeback.c:1715
writeback_sb_inodes+0x9fe/0x1610 fs/fs-writeback.c:1940
__writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011
wb_writeback+0x455/0xb90 fs/fs-writeback.c:2116
wb_check_background_flush fs/fs-writeback.c:2182 [inline]
wb_do_writeback fs/fs-writeback.c:2270 [inline]
wb_workfn+0xb47/0xe60 fs/fs-writeback.c:2298
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
INFO: task syz.4.72:4830 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.72 state:D stack:27408 pid: 4830 ppid: 4189 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
__lock_metapage+0x1a9/0x380 fs/jfs/jfs_metapage.c:49
lock_metapage fs/jfs/jfs_metapage.c:63 [inline]
__get_metapage+0x43e/0x1060 fs/jfs/jfs_metapage.c:640
ea_write+0x5df/0xdd0 fs/jfs/xattr.c:256
ea_put fs/jfs/xattr.c:626 [inline]
__jfs_setxattr+0x7cf/0x1000 fs/jfs/xattr.c:792
__jfs_xattr_set+0xd7/0x160 fs/jfs/xattr.c:941
__vfs_setxattr+0x3e0/0x420 fs/xattr.c:182
__vfs_setxattr_noperm+0x129/0x5e0 fs/xattr.c:216
vfs_setxattr+0x168/0x2f0 fs/xattr.c:303
do_setxattr fs/xattr.c:588 [inline]
setxattr+0x2da/0x300 fs/xattr.c:611
path_setxattr+0x142/0x280 fs/xattr.c:630
__do_sys_lsetxattr fs/xattr.c:653 [inline]
__se_sys_lsetxattr fs/xattr.c:649 [inline]
__x64_sys_lsetxattr+0xb4/0xd0 fs/xattr.c:649
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f8107284749
RSP: 002b:00007f81054ca038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd
RAX: ffffffffffffffda RBX: 00007f81074db090 RCX: 00007f8107284749
RDX: 0000200000000640 RSI: 0000200000000600 RDI: 00002000000005c0
RBP: 00007f8107308f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000009 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f81074db128 R14: 00007f81074db090 R15: 00007ffd743df548
Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:2/151:
#0: ffff888018d80138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc90001ee7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
#2: ffff88805d23a0e0 (&type->s_umount_key#83){++++}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff8880628cb008 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: jfs_commit_inode+0x1c7/0x520 fs/jfs/inode.c:108
1 lock held by udevd/3561:
1 lock held by dhcpcd/3853:
#0: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: __netlink_dump_start+0x11f/0x700 net/netlink/af_netlink.c:2352
2 locks held by getty/3944:
#0: ffff88814caa9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
2 locks held by kworker/0:3/4174:
#0: ffff888016872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc90002e2fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
1 lock held by udevd/4175:
#0: ffff888076d18f28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff888076d18f28 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x15d/0x2b0 mm/util.c:549
3 locks held by kworker/0:12/4763:
#0: ffff88801b8cf538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc90004aefd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
#2: ffff888023fd1220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
#2: ffff888023fd1220 (&dev->mutex){....}-{3:3}, at: hub_event+0x1a7/0x5560 drivers/usb/core/hub.c:5827
3 locks held by kworker/0:14/4768:
#0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc90004b1fd00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
#2: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
#2: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x347/0x6b0 kernel/rcu/tree_exp.h:845
4 locks held by syz.4.72/4830:
#0: ffff88805d23a460 (sb_writers#22){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
#1: ffff8880628cb3c0 (&type->i_mutex_dir_key#16){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#1: ffff8880628cb3c0 (&type->i_mutex_dir_key#16){++++}-{3:3}, at: vfs_setxattr+0x141/0x2f0 fs/xattr.c:302
#2: ffff8880628cb008 (&jfs_ip->commit_mutex){+.+.}-{3:3}, at: __jfs_xattr_set+0xb6/0x160 fs/jfs/xattr.c:940
#3: ffff8880628cb0a0 (&jfs_ip->xattr_sem){++++}-{3:3}, at: __jfs_setxattr+0xe1/0x1000 fs/jfs/xattr.c:678
2 locks held by udevd/4808:
#0: ffff888020664518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
#1: ffff888147648468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xaa/0xb90 drivers/block/loop.c:1366
3 locks held by kworker/u4:20/4988:
#0: ffff888016879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc9000479fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
#2: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
2 locks held by syz.4.550/8061:
#0: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:699 [inline]
#0: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3d/0x1b0 drivers/net/tun.c:3440
#1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
#1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x320/0x6b0 kernel/rcu/tree_exp.h:845
2 locks held by syz.0.557/8125:
#0: ffff888075574a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#0: ffff888075574a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:650 [inline]
#0: ffff888075574a10 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1346
#1: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: ip_mc_drop_socket+0x7b/0x270 net/ipv4/igmp.c:2702
=============================================
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 10/25/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 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 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729