syzbot

INFO: task syz-executor:4384 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:22080 pid:4384  ppid:1      flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 wb_wait_for_completion+0x162/0x280 fs/fs-writeback.c:191
 sync_inodes_sb+0x1b8/0x9e0 fs/fs-writeback.c:2750
 sync_filesystem+0x16d/0x220 fs/sync.c:64
 generic_shutdown_super+0x6b/0x340 fs/super.c:474
 kill_block_super+0x7c/0xe0 fs/super.c:1470
 deactivate_locked_super+0x93/0xf0 fs/super.c:332
 cleanup_mnt+0x463/0x4f0 fs/namespace.c:1191
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2fc5590a77
RSP: 002b:00007fff27f99578 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f2fc5613d7d RCX: 00007f2fc5590a77
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff27f99630
RBP: 00007fff27f99630 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fff27f9a6c0
R13: 00007f2fc5613d7d R14: 00000000000246f1 R15: 00007fff27f9a700
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/0:0/7:
 #0: 
ffff8880b8e3aad8
 (
&rq->__lock
){-.-.}-{2:2}
, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
 #1: 
ffff8880b8e27848
 (
&per_cpu_ptr(group->pcpu, cpu)->seq
){-.-.}-{0:0}
, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
4 locks held by kworker/u4:1/11:
 #0: 
ffff888144e70938
 (
(wq_completion)writeback
){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90000107d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #2: ffff88807a168650 (sb_internal#2
){.+.+}-{0:0}
, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4571 [inline]
, at: xfs_bmapi_convert_delalloc+0x2fd/0x1480 fs/xfs/libxfs/xfs_bmap.c:4698
 #3: 
ffff8880631e9858
 (
&xfs_nondir_ilock_class
){++++}-{3:3}
, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4576 [inline]
, at: xfs_bmapi_convert_delalloc+0x329/0x1480 fs/xfs/libxfs/xfs_bmap.c:4698
1 lock held by rcu_tasks_kthre/12:
 #0: 
ffffffff8cb2b630
 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2be50 (
rcu_tasks_trace.tasks_gp_mutex
){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
2 locks held by kworker/0:1/14:
 #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90000137d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
1 lock held by khungtaskd/27:
 #0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
4 locks held by kworker/u4:2/40:
 #0: 
ffff888144e70938
 (
(wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: 
ffffc90000b17d00
 ((work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}
, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #2: ffff888059a4a650 (sb_internal#2){.+.+}-{0:0}, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4571 [inline]
 #2: ffff888059a4a650 (sb_internal#2){.+.+}-{0:0}, at: xfs_bmapi_convert_delalloc+0x2fd/0x1480 fs/xfs/libxfs/xfs_bmap.c:4698
 #3: 
ffff8880630a08d8
 (
&xfs_nondir_ilock_class
){++++}-{3:3}
, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4576 [inline]
, at: xfs_bmapi_convert_delalloc+0x329/0x1480 fs/xfs/libxfs/xfs_bmap.c:4698
4 locks held by kworker/u4:4/56:
 #0: 
ffff888144e70938
 (
(wq_completion)writeback
){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: 
ffffc90001577d00
 (
(work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}
, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #2: 
ffff88805c11c650
 (
sb_internal
#2
){.+.+}-{0:0}
, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4571 [inline]
, at: xfs_bmapi_convert_delalloc+0x2fd/0x1480 fs/xfs/libxfs/xfs_bmap.c:4698
 #3: 
ffff8880632d9858
 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4576 [inline]
 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_bmapi_convert_delalloc+0x329/0x1480 fs/xfs/libxfs/xfs_bmap.c:4698
2 locks held by getty/4028:
 #0: ffff88802fb7c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: 
ffffc9000327b2f0
 (
&ldata->atomic_read_lock
){+.+.}-{3:3}
, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
2 locks held by syz-executor/4384:
 #0: 
ffff88807a1680e0
 (
&type->s_umount_key
#53
){+.+.}-{3:3}
, at: deactivate_super+0xa0/0xd0 fs/super.c:362
 #1: 
ffff8880244447d0
 (
&bdi->wb_switch_rwsem
){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
){+.+.}-{3:3}, at: sync_inodes_sb+0x19c/0x9e0 fs/fs-writeback.c:2748
2 locks held by syz-executor/4475:
 #0: 
ffff88805c11c0e0
 (
&type->s_umount_key
#53
){+.+.}-{3:3}
, at: deactivate_super+0xa0/0xd0 fs/super.c:362
 #1: ffff8880244527d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff8880244527d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x19c/0x9e0 fs/fs-writeback.c:2748
2 locks held by syz-executor/4504:
 #0: ffff8880237480e0
 (
&type->s_umount_key
#53
){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362
 #1: ffff8880244607d0
 (
&bdi->wb_switch_rwsem
){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
){+.+.}-{3:3}, at: sync_inodes_sb+0x19c/0x9e0 fs/fs-writeback.c:2748
4 locks held by kworker/u4:6/4513:
 #0: 
ffff888144e70938
 (
(wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: 
ffffc900037b7d00
 (
(work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #2: ffff888053fd4650 (sb_internal#2){.+.+}-{0:0}
, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4571 [inline]
, at: xfs_bmapi_convert_delalloc+0x2fd/0x1480 fs/xfs/libxfs/xfs_bmap.c:4698
 #3: 
ffff8880632df558
 (
&xfs_nondir_ilock_class
){++++}-{3:3}
, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4576 [inline]
, at: xfs_bmapi_convert_delalloc+0x329/0x1480 fs/xfs/libxfs/xfs_bmap.c:4698
4 locks held by kworker/u4:7/4526:
 #0: 
ffff888144e70938
 (
(wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003817d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #2: ffff888023748650
 (
sb_internal
#2
){.+.+}-{0:0}
, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4571 [inline]
, at: xfs_bmapi_convert_delalloc+0x2fd/0x1480 fs/xfs/libxfs/xfs_bmap.c:4698
 #3: 
ffff8880631ece98 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_bmapi_convert_one_delalloc fs/xfs/libxfs/xfs_bmap.c:4576 [inline]
ffff8880631ece98 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_bmapi_convert_delalloc+0x329/0x1480 fs/xfs/libxfs/xfs_bmap.c:4698
2 locks held by syz-executor/4536:
 #0: ffff888059a4a0e0 (&type->s_umount_key#53){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362
 #1: ffff8880244667d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff8880244667d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x19c/0x9e0 fs/fs-writeback.c:2748
3 locks held by kworker/u4:8/4562:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003a07d00 ((linkwatch_work).work
){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8dd416e8 (
rtnl_mutex
){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
2 locks held by syz-executor/4575:
 #0: ffff888053fd40e0 (&type->s_umount_key#53){+.+.}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362
 #1: ffff888143b647d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff888143b647d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x19c/0x9e0 fs/fs-writeback.c:2748
2 locks held by syz-executor/4642:
 #0: 
ffffffff8dd416e8
 (
rtnl_mutex
){+.+.}-{3:3}
, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6147
 #1: 
ffffffff8cb30978
 (
rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962

=============================================

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 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4456 Comm: kworker/1:27 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: xfs-buf/loop4 xfs_buf_ioend_work
RIP: 0010:__cmpxchg_double_slab+0x11f/0x250 mm/slub.c:516
Code: e8 36 e0 2f ff eb 27 0f 0b f6 47 0b 40 0f 84 3a ff ff ff 41 8d 46 20 a8 0f 75 5e 4c 89 c9 4c 89 e0 4c 89 fa f0 49 0f c7 4e 20 <b0> 01 74 04 f3 90 31 c0 5b 41 5c 41 5d 41 5e 41 5f c3 e8 fa df 2f
RSP: 0018:ffffc900001e06e0 EFLAGS: 00000046
RAX: ffff88801fbb0140 RBX: 0000000000000000 RCX: 00000000800c000c
RDX: 00000000800c0008 RSI: ffffea00007eec00 RDI: ffff888141266000
RBP: ffffea00007eec00 R08: 0000000000000000 R09: 00000000800c000c
R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: ffff88801fbb0140
R13: ffff8880b8f44400 R14: ffffea00007eec00 R15: 00000000800c0008
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbb22d17d60 CR3: 000000007989f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 get_freelist mm/slub.c:2981 [inline]
 ___slab_alloc+0x2f1/0x1230 mm/slub.c:3064
 __slab_alloc mm/slub.c:3240 [inline]
 slab_alloc_node mm/slub.c:3325 [inline]
 kmem_cache_alloc_node+0x1e5/0x320 mm/slub.c:3404
 __alloc_skb+0xfc/0x7e0 net/core/skbuff.c:505
 skb_copy+0x139/0x790 net/core/skbuff.c:1732
 mac80211_hwsim_tx_frame_no_nl+0xd6e/0x1330 drivers/net/wireless/mac80211_hwsim.c:1729
 mac80211_hwsim_tx_frame+0x1b5/0x200 drivers/net/wireless/mac80211_hwsim.c:2058
 mac80211_hwsim_beacon_tx+0x61e/0xae0 drivers/net/wireless/mac80211_hwsim.c:2121
 __iterate_interfaces+0x243/0x500 net/mac80211/util.c:788
 ieee80211_iterate_active_interfaces_atomic+0xd7/0x170 net/mac80211/util.c:824
 mac80211_hwsim_beacon+0xb7/0x1b0 drivers/net/wireless/mac80211_hwsim.c:2147
 __run_hrtimer kernel/time/hrtimer.c:1747 [inline]
 __hrtimer_run_queues+0x554/0xd60 kernel/time/hrtimer.c:1811
 hrtimer_run_softirq+0x183/0x2a0 kernel/time/hrtimer.c:1828
 handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:1948 [inline]
RIP: 0010:vprintk_emit+0x461/0x680 kernel/printk/printk.c:2302
Code: 85 8f 01 00 00 e8 2f ba 1a 00 41 89 df 4d 85 f6 48 8b 1c 24 75 07 e8 1e ba 1a 00 eb 06 e8 17 ba 1a 00 fb 48 c7 c7 40 ef b1 8c <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 37 db
RSP: 0018:ffffc900035277c0 EFLAGS: 00000293
RAX: ffffffff81661c49 RBX: ffffffff81661af5 RCX: ffff88802d633b80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8cb1ef40
RBP: ffffc900035278b0 R08: dffffc0000000000 R09: fffffbfff215c468
R10: fffffbfff215c468 R11: 1ffffffff215c467 R12: dffffc0000000000
R13: 1ffff920006a4efc R14: 0000000000000200 R15: 000000000000004b
 _printk+0xcc/0x110 kernel/printk/printk.c:2328
 print_hex_dump+0x1a5/0x260 lib/hexdump.c:285
 xfs_hex_dump+0x39/0x50 fs/xfs/xfs_message.c:110
 xfs_buf_verifier_error+0x1c8/0x290 fs/xfs/xfs_error.c:441
 xfs_allocbt_read_verify+0x53/0xd0 fs/xfs/libxfs/xfs_alloc_btree.c:-1
 xfs_buf_ioend+0x27a/0x780 fs/xfs/xfs_buf.c:1303
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>