rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P20135/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=115825, q=1678 ncpus=1)
task:syz.5.2938 state:R running task stack:28160 pid:20135 tgid:20131 ppid:12936 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0xfee/0x6120 kernel/sched/core.c:6908
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7235
irqentry_exit+0x17b/0x670 kernel/entry/common.c:239
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x5e/0x380 kernel/locking/lockdep.c:5872
Code: 05 fb f8 28 12 83 f8 07 0f 87 f0 00 00 00 48 0f a3 05 c6 74 f5 0e 0f 82 c2 02 00 00 8b 35 8e a8 f5 0e 85 f6 0f 85 dd 00 00 00 <48> 8b 44 24 30 65 48 2b 05 9d f8 28 12 0f 85 02 03 00 00 48 83 c4
RSP: 0018:ffffc90000bb7908 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8de57650 RDI: ffffffff8c1af920
RBP: ffffffff8e7e9220 R08: 0000000086db7919 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0xd1/0x1ea0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
save_stack+0x162/0x1e0 mm/page_owner.c:165
__reset_page_owner+0x84/0x190 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
__free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978
kimage_free_page_list+0x130/0x240 kernel/kexec_core.c:326
kimage_alloc_normal_control_pages kernel/kexec_core.c:391 [inline]
kimage_alloc_control_pages+0x3f2/0xa20 kernel/kexec_core.c:472
kimage_alloc_init kernel/kexec.c:67 [inline]
do_kexec_load+0x275/0x810 kernel/kexec.c:130
__do_sys_kexec_load kernel/kexec.c:261 [inline]
__se_sys_kexec_load kernel/kexec.c:242 [inline]
__x64_sys_kexec_load+0x1bf/0x230 kernel/kexec.c:242
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa70ff9c799
RSP: 002b:00007fa710f36028 EFLAGS: 00000246 ORIG_RAX: 00000000000000f6
RAX: ffffffffffffffda RBX: 00007fa710215fa0 RCX: 00007fa70ff9c799
RDX: 0000200000000040 RSI: 0000000000000002 RDI: 0000000000000005
RBP: 00007fa710032bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa710216038 R14: 00007fa710215fa0 R15: 00007ffe47ade8f8
rcu: rcu_preempt kthread timer wakeup didn't happen for 10497 jiffies! g115825 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=64460
rcu: rcu_preempt kthread starved for 10498 jiffies! g115825 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:27832 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0xfee/0x6120 kernel/sched/core.c:6908
__schedule_loop kernel/sched/core.c:6990 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7005
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
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: 1300 Comm: aoe_tx0 Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 d6 8a 54 f6 48 89 df e8 be da 54 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 35 fa 44 f6 65 8b 05 5e 7e 7d 08 85 c0 74 16 5b
RSP: 0018:ffffc9000573f968 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffffffff9b48d7c0 RCX: 0000000000000004
RDX: 0000000000000000 RSI: ffffffff8de7d6b1 RDI: ffffffff8c1af920
RBP: 0000000000000293 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8f515da0
R13: ffffffff9b48d8c8 R14: 0000000000000000 R15: ffffffff9b48d900
FS: 0000000000000000(0000) GS:ffff88812434b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f86125ce69c CR3: 0000000036636000 CR4: 00000000003526f0
Call Trace:
spin_unlock_irqrestore include/linux/spinlock.h:407 [inline]
uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline]
uart_port_unlock_deref drivers/tty/serial/serial_core.c:91 [inline]
uart_port_unlock_deref drivers/tty/serial/serial_core.c:88 [inline]
uart_write_room+0x2d2/0x930 drivers/tty/serial/serial_core.c:647
tty_write_room+0x66/0x90 drivers/tty/tty_ioctl.c:69
handle_tx+0x14a/0x620 drivers/net/caif/caif_serial.c:212
__netdev_start_xmit include/linux/netdevice.h:5292 [inline]
netdev_start_xmit include/linux/netdevice.h:5301 [inline]
xmit_one net/core/dev.c:3871 [inline]
dev_hard_start_xmit+0x121/0x7d0 net/core/dev.c:3887
__dev_queue_xmit+0x32c1/0x4800 net/core/dev.c:4837
dev_queue_xmit include/linux/netdevice.h:3384 [inline]
tx+0xc4/0x130 drivers/block/aoe/aoenet.c:62
kthread+0x1d8/0x3c0 drivers/block/aoe/aoecmd.c:1241
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245