syzbot


WARNING in delayed_work_timer_fn (3)

Status: upstream: reported on 2025/08/15 19:10
Reported-by: syzbot+8aa7ee597d79feab5ef8@syzkaller.appspotmail.com
First crash: 166d, last: 23d
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in delayed_work_timer_fn arm -1 syz 308 2d02h 951d 0/29 upstream: reported syz repro on 2023/06/23 03:48
linux-6.1 WARNING in delayed_work_timer_fn (2) -1 35 299d 779d 0/3 auto-obsoleted due to no activity on 2025/07/13 12:01
linux-6.1 WARNING in delayed_work_timer_fn -1 2 918d 1021d 0/3 auto-obsoleted due to no activity on 2023/11/02 17:34

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 11 at kernel/workqueue.c:1441 __queue_work+0xf9c/0x123c kernel/workqueue.c:1441
Modules linked in:
CPU: 1 PID: 11 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Workqueue: writeback wb_workfn (flush-7:3)
pstate: 424000c5 (nZcv daIF +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : __queue_work+0xf9c/0x123c kernel/workqueue.c:1441
lr : __queue_work+0xf9c/0x123c kernel/workqueue.c:1441
sp : ffff800008017b30
x29: ffff800008017b70 x28: 1fffe000181356f1 x27: 0000000000000008
x26: ffff700001002f84 x25: dfff800000000000 x24: ffff0000d8831800
x23: ffff0000d88319c0 x22: ffff0000c09ab788 x21: 1fffe000181356f1
x20: 00000000000b0012 x19: ffff0000dcfa8bc0 x18: ffff800011a5bd40
x17: ffff80018a7b9000 x16: ffff8000082d3aa8 x15: 0000000000000000
x14: 0000000000000100 x13: 1ffff00002a0a0b1 x12: 0000000000ff0100
x11: ff008000081f318c x10: 0000000000000000 x9 : ffff8000081f318c
x8 : ffff0000c09ab780 x7 : ffff8000083b1064 x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : ffff800013a787c0
x2 : ffff0000dcfa8bc0 x1 : 0000000000000100 x0 : 0000000000000000
Call trace:
 __queue_work+0xf9c/0x123c kernel/workqueue.c:1441
 delayed_work_timer_fn+0x74/0x90 kernel/workqueue.c:1646
 call_timer_fn+0x1b8/0x964 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1747 [inline]
 __run_timers+0x4c0/0x6d8 kernel/time/timer.c:2023
 run_timer_softirq+0x7c/0x114 kernel/time/timer.c:2036
 handle_softirqs+0x318/0xc6c kernel/softirq.c:596
 __do_softirq+0x14/0x20 kernel/softirq.c:630
 ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:80
 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:897
 do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:85
 invoke_softirq kernel/softirq.c:477 [inline]
 __irq_exit_rcu+0x23c/0x43c kernel/softirq.c:679
 irq_exit_rcu+0x14/0x84 kernel/softirq.c:691
 __el1_irq arch/arm64/kernel/entry-common.c:472 [inline]
 el1_interrupt+0x38/0x54 arch/arm64/kernel/entry-common.c:486
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491
 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline]
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
 _raw_spin_unlock_irqrestore+0x58/0xac kernel/locking/spinlock.c:194
 __debug_check_no_obj_freed lib/debugobjects.c:988 [inline]
 debug_check_no_obj_freed+0x450/0x46c lib/debugobjects.c:1009
 slab_free_hook mm/slub.c:1704 [inline]
 slab_free_freelist_hook+0x104/0x1ec mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 kmem_cache_free+0x11c/0x324 mm/slub.c:3709
 add_free_nid+0x6d0/0x838 fs/f2fs/node.c:2368
 scan_free_nid_bits fs/f2fs/node.c:2465 [inline]
 __f2fs_build_free_nids fs/f2fs/node.c:2499 [inline]
 f2fs_build_free_nids+0x418/0xeb0 fs/f2fs/node.c:2557
 f2fs_balance_fs_bg+0x130/0x83c fs/f2fs/segment.c:470
 f2fs_write_node_pages+0x128/0x5e4 fs/f2fs/node.c:2135
 do_writepages+0x2c0/0x4fc mm/page-writeback.c:2491
 __writeback_single_inode+0x164/0x157c fs/fs-writeback.c:1622
 writeback_sb_inodes+0x824/0x1404 fs/fs-writeback.c:1913
 wb_writeback+0x400/0xfb0 fs/fs-writeback.c:2087
 wb_do_writeback fs/fs-writeback.c:2230 [inline]
 wb_workfn+0x34c/0xd98 fs/fs-writeback.c:2270
 process_one_work+0x7f4/0x13a8 kernel/workqueue.c:2292
 worker_thread+0x8c8/0xfbc kernel/workqueue.c:2439
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850
irq event stamp: 761721
hardirqs last  enabled at (761720): [<ffff8000081a95b4>] __local_bh_enable_ip+0x1f8/0x380 kernel/softirq.c:426
hardirqs last disabled at (761721): [<ffff8000119e5154>] __raw_spin_lock_irq include/linux/spinlock_api_smp.h:117 [inline]
hardirqs last disabled at (761721): [<ffff8000119e5154>] _raw_spin_lock_irq+0x34/0x9c kernel/locking/spinlock.c:170
softirqs last  enabled at (761654): [<ffff8000081aa3e0>] softirq_handle_end kernel/softirq.c:439 [inline]
softirqs last  enabled at (761654): [<ffff8000081aa3e0>] handle_softirqs+0xaf8/0xc6c kernel/softirq.c:624
softirqs last disabled at (761703): [<ffff800008020164>] __do_softirq+0x14/0x20 kernel/softirq.c:630
---[ end trace 0000000000000000 ]---
vkms_vblank_simulate: vblank timer overrun

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/05 20:16 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in delayed_work_timer_fn
2025/11/09 17:29 linux-6.1.y f6e38ae624cf 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in delayed_work_timer_fn
2025/08/25 18:24 linux-6.1.y 0bc96de781b4 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in delayed_work_timer_fn
2025/08/21 05:35 linux-6.1.y 0bc96de781b4 0b9605c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in delayed_work_timer_fn
2025/08/15 19:09 linux-6.1.y 0bc96de781b4 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in delayed_work_timer_fn
* Struck through repros no longer work on HEAD.