rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8140/1:b..l rcu: (detected by 0, t=10502 jiffies, g=25237, q=1014 ncpus=2) task:sed state:R running task stack:23624 pid:8140 tgid:8140 ppid:8139 task_flags:0x400000 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0x57/0x2f0 kernel/locking/lockdep.c:5829 Code: 93 65 48 8b 45 00 48 89 44 24 38 0f 1f 44 00 00 65 8b 05 e0 11 ca 11 83 f8 08 0f 83 b4 01 00 00 89 c0 48 0f a3 05 c9 fe c0 0e <73> 16 e8 72 be 09 00 84 c0 75 0d f6 05 af e6 aa 0e 01 0f 84 9b 01 RSP: 0018:ffffc9000444ef98 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffffff8ed3e440 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8ed3e440 RBP: ffffffff93691020 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000002 R14: ffffffff81ad660d R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] is_module_text_address+0x3a/0x1f0 kernel/module/main.c:3743 kernel_text_address+0x96/0xe0 kernel/extable.c:119 __kernel_text_address+0xd/0x40 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0xff/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4151 [inline] slab_alloc_node mm/slub.c:4200 [inline] kmem_cache_alloc_noprof+0x1e1/0x390 mm/slub.c:4207 kmem_alloc_batch lib/debugobjects.c:371 [inline] fill_pool+0x262/0x690 lib/debugobjects.c:403 debug_objects_fill_pool lib/debugobjects.c:725 [inline] debug_object_activate+0x4c1/0x5c0 lib/debugobjects.c:814 debug_rcu_head_queue kernel/rcu/rcu.h:224 [inline] __call_rcu_common kernel/rcu/tree.c:3067 [inline] call_rcu+0x99/0xad0 kernel/rcu/tree.c:3202 slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4646 [inline] kmem_cache_free+0x312/0x410 mm/slub.c:4748 fput_close+0x1f2/0x270 fs/file_table.c:582 path_openat+0x2f18/0x35d0 fs/namei.c:4013 do_filp_open+0x284/0x4e0 fs/namei.c:4031 do_sys_openat2+0x12b/0x1d0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_openat fs/open.c:1460 [inline] __se_sys_openat fs/open.c:1455 [inline] __x64_sys_openat+0x249/0x2a0 fs/open.c:1455 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6b8e839a46 RSP: 002b:00007fffdbb69b58 EFLAGS: 00000287 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fffdbb69db8 RCX: 00007f6b8e839a46 RDX: 0000000000080000 RSI: 00007fffdbb69bd0 RDI: 00000000ffffff9c RBP: 00007fffdbb69bc0 R08: 0000000000080000 R09: 00007fffdbb69bd0 R10: 0000000000000000 R11: 0000000000000287 R12: 00007fffdbb69bd0 R13: 0000000000000001 R14: 00007fffdbb69d9f R15: 00000000ffffffff rcu: rcu_preempt kthread timer wakeup didn't happen for 10551 jiffies! g25237 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=20346 rcu: rcu_preempt kthread starved for 10557 jiffies! g25237 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:I stack:26688 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 1297 Comm: aoe_tx0 Not tainted 6.14.0-next-20250404-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xd9/0x140 kernel/locking/spinlock.c:194 Code: 9c 8f 44 24 20 42 80 3c 2b 00 74 08 4c 89 f7 e8 fd 9b f9 f5 f6 44 24 21 02 75 55 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 e2 b5 5c f5 65 8b 05 8b 2c 35 07 85 c0 74 46 48 c7 04 24 0e 36 RSP: 0018:ffffc900044df780 EFLAGS: 00000206 RAX: ccc999bf751e6800 RBX: 1ffff9200089bef4 RCX: 0000000000000002 RDX: 0000000000000002 RSI: ffffffff8e6a4c4b RDI: 0000000000000001 RBP: ffffc900044df820 R08: ffffffff905ffd37 R09: 1ffffffff20bffa6 R10: dffffc0000000000 R11: fffffbfff20bffa7 R12: 1ffff9200089bef0 R13: dffffc0000000000 R14: ffffc900044df7a0 R15: 0000000000000246 FS: 0000000000000000(0000) GS:ffff888124f8f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3bd199b720 CR3: 00000000632c0000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:786 [inline] uart_write_room+0x3c3/0x920 drivers/tty/serial/serial_core.c:649 handle_tx+0x164/0x640 drivers/net/caif/caif_serial.c:212 __netdev_start_xmit include/linux/netdevice.h:5201 [inline] netdev_start_xmit include/linux/netdevice.h:5210 [inline] xmit_one net/core/dev.c:3780 [inline] dev_hard_start_xmit+0x2d4/0x840 net/core/dev.c:3796 __dev_queue_xmit+0x1b80/0x3f60 net/core/dev.c:4633 dev_queue_xmit include/linux/netdevice.h:3350 [inline] tx+0x6b/0x180 drivers/block/aoe/aoenet.c:62 kthread+0x23c/0x470 drivers/block/aoe/aoecmd.c:1237 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245