INFO: rcu detected stall in ext4_end_io_rsv

Kernel	Title	Rank 🛈	Repro	Cause bisect	Count	Last	Reported	Patched	Status
linux-5.15	INFO: rcu detected stall in ext4_end_io_rsv_work origin:lts-only	1	syz		1	10d	10d	0/3	upstream: reported syz repro on 2025/09/22 08:45
upstream	INFO: rcu detected stall in ext4_end_io_rsv_work (3) mm ext4	1	C	error	2	6d17h	143d	0/29	upstream: reported C repro on 2025/05/12 09:11
upstream	INFO: rcu detected stall in ext4_end_io_rsv_work (2) mm	1			1	413d	413d	0/29	auto-obsoleted due to no activity on 2024/11/13 20:18

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): ------------[ cut here ]------------ WARNING: CPU: 0 PID: 362 at kernel/sched/core.c:3013 rq_unlock kernel/sched/sched.h:1326 [inline] WARNING: CPU: 0 PID: 362 at kernel/sched/core.c:3013 try_invoke_on_locked_down_task+0x21d/0x2f0 kernel/sched/core.c:3019 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 362 Comm: kworker/u4:1 Not tainted 5.9.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work Call Trace: <IRQ> __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 panic+0x382/0x7fb kernel/panic.c:231 __warn.cold+0x20/0x4b kernel/panic.c:600 report_bug+0x1bd/0x210 lib/bug.c:198 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536 RIP: 0010:try_invoke_on_locked_down_task+0x21d/0x2f0 kernel/sched/core.c:3013 Code: 45 31 f6 49 39 c0 74 3a 8b 74 24 38 49 8d 78 18 4c 89 04 24 e8 24 e6 08 00 4c 8b 04 24 4c 89 c7 e8 e8 5c d6 06 e9 20 ff ff ff <0f> 0b e9 7d fe ff ff 4c 89 ee 48 89 ef 41 ff d4 41 89 c6 e9 08 ff RSP: 0018:ffffc90000007be0 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 1ffff92000000f7e RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8162ca80 RDI: ffff8880a855c500 RBP: ffff8880a855c500 R08: 0000000000000033 R09: ffffffff8a05ae23 R10: 00000000000060dc R11: 0000000000000001 R12: ffffffff8162ca80 R13: ffffc90000007d08 R14: ffff8880a855c500 R15: 0000000000000000 rcu_print_task_stall kernel/rcu/tree_stall.h:267 [inline] print_other_cpu_stall kernel/rcu/tree_stall.h:475 [inline] check_cpu_stall kernel/rcu/tree_stall.h:634 [inline] rcu_pending kernel/rcu/tree.c:3637 [inline] rcu_sched_clock_irq.cold+0x97e/0xdfd kernel/rcu/tree.c:2519 update_process_times+0x25/0xa0 kernel/time/timer.c:1710 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176 tick_sched_timer+0x1d1/0x2a0 kernel/time/tick-sched.c:1328 __run_hrtimer kernel/time/hrtimer.c:1524 [inline] __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1588 hrtimer_interrupt+0x334/0x940 kernel/time/hrtimer.c:1650 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x147/0x5f0 arch/x86/kernel/apic/apic.c:1097 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 </IRQ> __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] sysvec_apic_timer_interrupt+0xb2/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 RIP: 0010:queued_read_lock_slowpath+0x120/0x2a0 kernel/locking/qrwlock.c:49 Code: 85 3a 01 00 00 8b 03 84 c0 74 36 48 b8 00 00 00 00 00 fc ff df 49 89 de 48 89 dd 49 c1 ee 03 83 e5 07 49 01 c6 83 c5 03 f3 90 <41> 0f b6 06 40 38 c5 7c 08 84 c0 0f 85 13 01 00 00 8b 03 84 c0 75 RSP: 0018:ffffc90006247900 EFLAGS: 00000286 RAX: 00000000000002ff RBX: ffff88802e7ead78 RCX: ffffffff815cf67a RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88802e7ead78 RBP: 0000000000000003 R08: 0000000000000001 R09: ffff88802e7ead7b R10: ffffed1005cfd5af R11: 0000000000000000 R12: 1ffff92000c48f21 R13: ffff88802e7ead7c R14: ffffed1005cfd5af R15: ffffc90006247b64 ext4_es_lookup_extent+0xa7/0xce0 fs/ext4/extents_status.c:915 ext4_map_blocks+0x15b/0x1650 fs/ext4/inode.c:517 ext4_convert_unwritten_extents+0x1c6/0x570 fs/ext4/extents.c:4749 ext4_convert_unwritten_io_end_vec+0x122/0x270 fs/ext4/extents.c:4788 ext4_end_io_end fs/ext4/page-io.c:187 [inline] ext4_do_flush_completed_IO fs/ext4/page-io.c:260 [inline] ext4_end_io_rsv_work+0x2b3/0x660 fs/ext4/page-io.c:274 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Kernel Offset: disabled Rebooting in 86400 seconds..