INFO: task kworker/u4:5:4279 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:5 state:D stack:21304 pid: 4279 ppid: 2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
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
rwsem_down_write_slowpath+0xc87/0x1260 kernel/locking/rwsem.c:1165
f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
f2fs_write_inode+0x531/0x760 fs/f2fs/inode.c:745
write_inode fs/fs-writeback.c:1505 [inline]
__writeback_single_inode+0x6c3/0xda0 fs/fs-writeback.c:1715
writeback_sb_inodes+0xa4e/0x1680 fs/fs-writeback.c:1940
__writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011
wb_writeback+0x46f/0xbe0 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+0xbd6/0xf20 fs/fs-writeback.c:2298
process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Showing all locks held in the system:
4 locks held by kworker/u4:0/9:
#0: ffff888142990138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc90000ce7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff88804c48e0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88804c4811b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
1 lock held by khungtaskd/27:
#0: ffffffff8c31f320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:1/144:
#0: ffff888142990138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc9000171fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff88805cc4a0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff8880799ad1b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by kworker/u4:3/1221:
#0: ffff888142990138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc900058a7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff888025b8c0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff8880789d91b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by kworker/u4:4/2986:
#0: ffff888142990138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc9000d67fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff888078ed40e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88802abdd1b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
2 locks held by getty/3951:
#0: ffff88814d4c5098 (&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+0x5df/0x1a70 drivers/tty/n_tty.c:2158
4 locks held by kworker/u4:5/4279:
#0: ffff888142990138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc900034bfd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff888025ac60e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff8880742691b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
5 locks held by syz.0.17/5118:
7 locks held by syz.1.18/5140:
4 locks held by kworker/u4:6/5158:
#0: ffff888142990138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc900032afd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff8880748ca0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88807b1fd1b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
5 locks held by syz.2.19/5160:
6 locks held by syz.3.20/5185:
4 locks held by kworker/u4:8/5204:
#0: ffff888142990138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc9000340fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff888076e5a0e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff8880513a51b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by syz.4.21/5215:
4 locks held by kworker/u4:10/5242:
#0: ffff888142990138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
#1: ffffc9000353fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
#2: ffff88807d7c00e0 (&type->s_umount_key#54){.+.+}-{3:3}, at: trylock_super+0x1c/0xf0 fs/super.c:418
#3: ffff88807de291b0 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x47e/0x650 fs/f2fs/segment.c:528
4 locks held by syz.5.22/5245:
4 locks held by syz.6.23/5279:
7 locks held by syz.7.24/5310:
2 locks held by syz-executor/5312:
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5160 Comm: syz.2.19 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__radix_tree_lookup lib/radix-tree.c:-1 [inline]
RIP: 0010:radix_tree_lookup+0x14a/0x280 lib/radix-tree.c:817
Code: ff 02 04 00 00 0f 84 a2 00 00 00 4c 89 e0 48 c1 e8 03 0f b6 04 28 84 c0 75 78 45 0f b6 2c 24 41 0f b6 f5 31 ff e8 96 29 73 fd <45> 89 fc 41 83 e4 03 bf 02 00 00 00 4c 89 e6 e8 02 2b 73 fd 49 83
RSP: 0018:ffffc900032bf1c0 EFLAGS: 00000293
RAX: ffffffff84060eda RBX: 000000000000000a RCX: ffff88802a618000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffea00007c98b7 R09: 1ffffd40000f9316
R10: dffffc0000000000 R11: fffff940000f9317 R12: ffff88806f2318c0
R13: 0000000000000000 R14: ffffc900032bf8a8 R15: ffff888075fd1000
FS: 00007fcdb6b2c6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe94303ce38 CR3: 00000000799e3000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
find_gc_inode fs/f2fs/gc.c:840 [inline]
gc_data_segment fs/f2fs/gc.c:1518 [inline]
do_garbage_collect+0x2429/0x6300 fs/f2fs/gc.c:1671
f2fs_gc+0x8da/0x1950 fs/f2fs/gc.c:1765
f2fs_balance_fs+0x492/0x650 fs/f2fs/segment.c:529
f2fs_map_blocks+0x1953/0x3300 fs/f2fs/data.c:1706
expand_inode_data+0x4bf/0x700 fs/f2fs/file.c:1717
f2fs_fallocate+0x423/0x8c0 fs/f2fs/file.c:1819
vfs_fallocate+0x587/0x6f0 fs/open.c:308
ksys_fallocate fs/open.c:331 [inline]
__do_sys_fallocate fs/open.c:339 [inline]
__se_sys_fallocate fs/open.c:337 [inline]
__x64_sys_fallocate+0xbd/0x100 fs/open.c:337
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: 0033:0x7fcdb74c8379
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007fcdb6b2c028 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fcdb7713fa0 RCX: 00007fcdb74c8379
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007fcdb755bd68 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000008800000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcdb7714038 R14: 00007fcdb7713fa0 R15: 00007ffcb12c1428