rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P15826/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=80085, q=726 ncpus=2)
task:syz.5.2502 state:R running task stack:26096 pid:15826 tgid:15825 ppid:14479 task_flags:0x40044c flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256
irqentry_exit+0x36/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x183/0x2f0 kernel/locking/lockdep.c:5893
Code: 0f c1 05 38 9e 0b 12 83 f8 01 0f 85 1d 01 00 00 9c 58 f6 c4 02 0f 85 08 01 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 4d 5c 0b 12 0f 85 58 01 00 00 48 83 c4 18 5b 41 5c 41
RSP: 0018:ffffc9000bbaee00 EFLAGS: 00000206
RAX: f5a65679beb89c00 RBX: ffffffff8e3c4460 RCX: ffffc9000bbaee0c
RDX: 0000000000000001 RSI: ffffffff8dadd953 RDI: ffffffff8bf1e3c0
RBP: 0000000000000001 R08: ffffffff911c6efe R09: 0000000000000000
R10: 0000000000000000 R11: 000000000000a833 R12: ffffffff816c4914
R13: 0000000000000202 R14: ffff888028838000 R15: 0000000000000002
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:897 [inline]
class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0x3f9/0x20a0 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
save_stack+0x160/0x1f0 mm/page_owner.c:156
__reset_page_owner+0x84/0x1a0 mm/page_owner.c:308
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
free_unref_folios+0xa31/0x1610 mm/page_alloc.c:2963
folios_put_refs+0x4be/0x750 mm/swap.c:1002
free_pages_and_swap_cache+0x245/0x4a0 mm/swap_state.c:355
__tlb_batch_free_encoded_pages+0xf9/0x290 mm/mmu_gather.c:136
tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:397 [inline]
tlb_flush_mmu+0xe9/0x5a0 mm/mmu_gather.c:404
zap_pte_range mm/memory.c:1893 [inline]
zap_pmd_range mm/memory.c:1946 [inline]
zap_pud_range mm/memory.c:1975 [inline]
zap_p4d_range mm/memory.c:1996 [inline]
unmap_page_range+0x1f1e/0x41b0 mm/memory.c:2017
unmap_single_vma.constprop.0+0x153/0x240 mm/memory.c:2060
unmap_vmas+0x218/0x470 mm/memory.c:2104
exit_mmap+0x1b2/0xb90 mm/mmap.c:1280
__mmput+0x12a/0x410 kernel/fork.c:1133
mmput+0x62/0x70 kernel/fork.c:1156
exit_mm kernel/exit.c:582 [inline]
do_exit+0x7c7/0x2bf0 kernel/exit.c:954
do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
get_signal+0x2671/0x26d0 kernel/signal.c:3034
arch_do_signal_or_restart+0x8f/0x7c0 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x85/0x130 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe2ca18eec9
RSP: 002b:00007fe2cb0f7038 EFLAGS: 00000246 ORIG_RAX: 0000000000000007
RAX: 0000000000000001 RBX: 00007fe2ca3e5fa0 RCX: 00007fe2ca18eec9
RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000200000000040
RBP: 00007fe2ca211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe2ca3e6038 R14: 00007fe2ca3e5fa0 R15: 00007ffe5521f1f8
rcu: rcu_preempt kthread timer wakeup didn't happen for 10544 jiffies! g80085 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=1 timer-softirq=65771
rcu: rcu_preempt kthread starved for 10550 jiffies! g80085 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
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:27584 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 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: 1 UID: 0 PID: 1297 Comm: aoe_tx0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [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 a6 47 30 f6 48 89 df e8 8e 9b 30 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 45 a6 20 f6 65 8b 05 7e a5 3b 08 85 c0 74 16 5b
RSP: 0018:ffffc9000458f958 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffffffff9ae082e0 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8db0330f RDI: ffffffff8bf1e3c0
RBP: 0000000000000293 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90832dd7 R11: 0000000000000001 R12: ffffffff8f072de0
R13: ffffffff9ae083e8 R14: 0000000000000000 R15: ffffffff9ae08420
FS: 0000000000000000(0000) GS:ffff888124ad9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffffd CR3: 000000005cb63000 CR4: 00000000003526f0
Call Trace:
spin_unlock_irqrestore include/linux/spinlock.h:406 [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+0x2d9/0x940 drivers/tty/serial/serial_core.c:647
tty_write_room+0x66/0x90 drivers/tty/tty_ioctl.c:69
handle_tx+0x14f/0x630 drivers/net/caif/caif_serial.c:212
__netdev_start_xmit include/linux/netdevice.h:5248 [inline]
netdev_start_xmit include/linux/netdevice.h:5257 [inline]
xmit_one net/core/dev.c:3845 [inline]
dev_hard_start_xmit+0x97/0x740 net/core/dev.c:3861
__dev_queue_xmit+0xa46/0x4490 net/core/dev.c:4763
dev_queue_xmit include/linux/netdevice.h:3365 [inline]
tx+0xcc/0x190 drivers/block/aoe/aoenet.c:62
kthread+0x1e4/0x3e0 drivers/block/aoe/aoecmd.c:1241
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245