INFO: task syz.4.63:6358 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.63 state:D stack:18488 pid:6358 tgid:6358 ppid:5831 task_flags:0x400640 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
__schedule_loop kernel/sched/core.c:6948 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6963
schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common kernel/sched/completion.c:121 [inline]
wait_for_common kernel/sched/completion.c:132 [inline]
wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:153
__flush_work+0x9b9/0xbc0 kernel/workqueue.c:4331
xfs_file_buffered_write+0x266/0x8a0 fs/xfs/xfs_file.c:1000
__kernel_write_iter+0x428/0x910 fs/read_write.c:619
dump_emit_page fs/coredump.c:1298 [inline]
dump_user_range+0x8a0/0xc90 fs/coredump.c:1372
elf_core_dump+0x3369/0x3960 fs/binfmt_elf.c:2111
coredump_write+0x1121/0x18b0 fs/coredump.c:1049
do_coredump fs/coredump.c:1126 [inline]
vfs_coredump+0x3321/0x3e60 fs/coredump.c:1200
get_signal+0x1108/0x1340 kernel/signal.c:3019
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop kernel/entry/common.c:75 [inline]
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
irqentry_exit+0x177/0x660 kernel/entry/common.c:196
exc_page_fault+0xab/0x100 arch/x86/mm/fault.c:1535
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7fed47f8f751
RSP: 002b:fffffffffffffe70 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007fed481e6090 RCX: 00007fed47f8f749
RDX: 0000000000000000 RSI: fffffffffffffe70 RDI: 0000000000008000
RBP: 00007fed48013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fed481e6128 R14: 00007fed481e6090 R15: 00007ffc6be5e1a8
Showing all locks held in the system:
5 locks held by kworker/0:1/10:
#0: ffff888140eb3148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc900000f7b80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2:
ffff888144f7b198
(
&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4ef0 drivers/usb/core/hub.c:5899
#3: ffff888026554198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#3: ffff888026554198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x430 drivers/base/dd.c:1006
#4: ffff888028217160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#4: ffff888028217160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x430 drivers/base/dd.c:1006
1 lock held by khungtaskd/31:
#0: ffffffff8e13f2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e13f2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e13f2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:5/145:
2 locks held by getty/5582:
#0: ffff88814d1b20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1:
ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211
3 locks held by syz-executor/5831:
#0: ffff88805322a420 (sb_writers#20){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499
#1: ffff888057638330 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline]
#1: ffff888057638330 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2864 [inline]
#1: ffff888057638330 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2875 [inline]
#1: ffff888057638330 (&inode->i_sb->s_type->i_mutex_dir_key/1){+.+.}-{4:4}, at: do_unlinkat+0x28c/0x5d0 fs/namei.c:5486
#2: ffff888057680330 (&sb->s_type->i_mutex_key#34){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
#2: ffff888057680330 (&sb->s_type->i_mutex_key#34){++++}-{4:4}, at: vfs_unlink+0xed/0x6c0 fs/namei.c:5421
4 locks held by udevd/5881:
#0: ffff88803276c418 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe20 fs/seq_file.c:183
#1: ffff888056097488 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172
#2:
ffff88805531a878 (kn->active#31){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
ffff88805531a878 (kn->active#31){.+.+}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173
#3: ffff88801dbdf198 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:900 [inline]
#3: ffff88801dbdf198 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
5 locks held by kworker/1:8/5937:
#0: ffff888140eb3148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc900045afb80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2: ffff888028ee3198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#2: ffff888028ee3198 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4ef0 drivers/usb/core/hub.c:5899
#3: ffff88801dbdf198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#3: ffff88801dbdf198 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x430 drivers/base/dd.c:1006
#4: ffff888056491160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
#4: ffff888056491160 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x430 drivers/base/dd.c:1006
4 locks held by kworker/0:10/6089:
#0: ffff888056275948 ((wq_completion)xfs-sync/loop4){+.+.}-{0:0}, at: process_one_work+0x841/0x15a0 kernel/workqueue.c:3254
#1: ffffc9000afb7b80 ((work_completion)(&mp->m_flush_inodes_work)){+.+.}-{0:0}, at: process_one_work+0x868/0x15a0 kernel/workqueue.c:3255
#2: ffff88805322a0e0 (&type->s_umount_key#77){++++}-{4:4}, at: xfs_flush_inodes_worker+0x45/0x80 fs/xfs/xfs_super.c:661
#3: ffff8880255d0820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:397 [inline]
#3: ffff8880255d0820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1ad/0xb40 fs/fs-writeback.c:2892
2 locks held by syz.4.63/6358:
#0:
ffff88805322a420 (sb_writers#20){.+.+}-{0:0}, at: do_coredump fs/coredump.c:1126 [inline]
ffff88805322a420 (sb_writers#20){.+.+}-{0:0}, at: vfs_coredump+0x3321/0x3e60 fs/coredump.c:1200
#1:
ffff888057680330 (&sb->s_type->i_mutex_key#34){++++}-{4:4}, at: xfs_ilock+0xee/0x370 fs/xfs/xfs_inode.c:149
1 lock held by syz-executor/6562:
#0:
ffffffff8e144e38
(rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
(rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:956
4 locks held by udevd/7337:
#0: ffff8880217bc8b8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe20 fs/seq_file.c:183
#1: ffff8880569ff088
(
&of->mutex
#2
){+.+.}-{4:4}
, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172
#2:
ffff88804d64c4b8
(
kn->active
#31){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#31){.+.+}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173
#3: ffff888026554198
(&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:900 [inline]
(&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
2 locks held by syz.3.352/7876:
#0: ffff88805322a0e0 (&type->s_umount_key#77){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
#0: ffff88805322a0e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
#1: ffff8880255d0820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:397 [inline]
#1: ffff8880255d0820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1ad/0xb40 fs/fs-writeback.c:2892
2 locks held by syz.3.352/7877:
#0: ffff88805322a0e0 (&type->s_umount_key#77){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline]
#0: ffff88805322a0e0 (&type->s_umount_key#77){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121
#1: ffff8880255d0820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:397 [inline]
#1: ffff8880255d0820 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1ad/0xb40 fs/fs-writeback.c:2892
2 locks held by syz.6.386/8002:
#0: ffffffff8f512448 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff8f512448 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436
#1: ffffffff8e144e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#1: ffffffff8e144e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:956
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [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:363 [inline]
watchdog+0xe40/0xe90 kernel/hung_task.c:557
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 145 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: writeback wb_workfn (flush-7:4)
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400
Code: e8 ae 60 a5 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 0f 09 0c fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90002e756f8 EFLAGS: 00000006
RAX: 1ffffffff33c0a05 RBX: 00000000000003f9 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc90002e758d0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff851c5760 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff99e05380 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff161d2ff8 CR3: 0000000031832000 CR4: 00000000003526f0
Call Trace:
serial_port_in include/linux/serial_core.h:806 [inline]
serial8250_console_write+0x584/0x1ba0 drivers/tty/serial/8250/8250_port.c:3306
console_emit_next_record kernel/printk/printk.c:3129 [inline]
console_flush_one_record kernel/printk/printk.c:3215 [inline]
console_flush_all+0x745/0xb60 kernel/printk/printk.c:3289
__console_flush_and_unlock kernel/printk/printk.c:3319 [inline]
console_unlock+0xbb/0x190 kernel/printk/printk.c:3359
vprintk_emit+0x4f8/0x5f0 kernel/printk/printk.c:2426
_printk+0xcf/0x120 kernel/printk/printk.c:2451
print_hex_dump+0x1a8/0x260 lib/hexdump.c:286
xfs_hex_dump+0x3d/0x50 fs/xfs/xfs_message.c:110
xfs_buf_verifier_error+0x1cc/0x2a0 fs/xfs/xfs_error.c:310
xfs_allocbt_read_verify+0x5f/0xe0 fs/xfs/libxfs/xfs_alloc_btree.c:-1
__xfs_buf_ioend+0x332/0x6d0 fs/xfs/xfs_buf.c:1174
xfs_buf_iowait+0x143/0x440 fs/xfs/xfs_buf.c:1381
_xfs_buf_read fs/xfs/xfs_buf.c:643 [inline]
xfs_buf_read_map+0x325/0xa30 fs/xfs/xfs_buf.c:709
xfs_trans_read_buf_map+0x1d7/0x8a0 fs/xfs/xfs_trans_buf.c:304
xfs_trans_read_buf fs/xfs/xfs_trans.h:212 [inline]
xfs_btree_read_buf_block+0x290/0x470 fs/xfs/libxfs/xfs_btree.c:1402
xfs_btree_lookup_get_block+0x28d/0x500 fs/xfs/libxfs/xfs_btree.c:1907
xfs_btree_lookup+0x4e1/0x1410 fs/xfs/libxfs/xfs_btree.c:2018
xfs_alloc_lookup fs/xfs/libxfs/xfs_alloc.c:166 [inline]
xfs_alloc_lookup_eq fs/xfs/libxfs/xfs_alloc.c:184 [inline]
xfs_alloc_fixup_trees+0x21b/0xd20 fs/xfs/libxfs/xfs_alloc.c:626
xfs_alloc_cur_finish+0xd5/0x480 fs/xfs/libxfs/xfs_alloc.c:1117
xfs_alloc_ag_vextent_near+0xd0d/0x11d0 fs/xfs/libxfs/xfs_alloc.c:1776
xfs_alloc_vextent_near_bno+0x2e7/0x560 fs/xfs/libxfs/xfs_alloc.c:3962
xfs_bmap_btalloc_filestreams fs/xfs/libxfs/xfs_bmap.c:3566 [inline]
xfs_bmap_btalloc fs/xfs/libxfs/xfs_bmap.c:3661 [inline]
xfs_bmapi_allocate+0x1af7/0x2e00 fs/xfs/libxfs/xfs_bmap.c:3938
xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4447 [inline]
xfs_bmapi_convert_delalloc+0x7e2/0x1430 fs/xfs/libxfs/xfs_bmap.c:4503
xfs_map_blocks fs/xfs/xfs_aops.c:445 [inline]
xfs_writeback_range+0x674/0xf30 fs/xfs/xfs_aops.c:489
iomap_writeback_range fs/iomap/buffered-io.c:1744 [inline]
iomap_writeback_folio+0x1408/0x23f0 fs/iomap/buffered-io.c:1862
iomap_writepages+0x162/0x2d0 fs/iomap/buffered-io.c:1922
xfs_vm_writepages+0x296/0x310 fs/xfs/xfs_aops.c:701
do_writepages+0x32e/0x550 mm/page-writeback.c:2598
__writeback_single_inode+0x133/0x1240 fs/fs-writeback.c:1737
writeback_sb_inodes+0x93a/0x1870 fs/fs-writeback.c:2030
wb_writeback+0x42b/0xaa0 fs/fs-writeback.c:2216
wb_do_writeback fs/fs-writeback.c:2363 [inline]
wb_workfn+0x3f9/0xed0 fs/fs-writeback.c:2403
process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
process_scheduled_works kernel/workqueue.c:3362 [inline]
worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246