rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7347/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=18977, q=256 ncpus=2)
task:syz.0.315 state:R running task stack:22856 pid:7347 tgid:7347 ppid:5826 task_flags:0x40004c flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5254 [inline]
__schedule+0x17c4/0x4d60 kernel/sched/core.c:6862
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7189
irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline]
RIP: 0010:lock_acquire+0x58/0x360 kernel/locking/lockdep.c:5831
Code: 8b 05 ec f5 d5 10 48 89 44 24 58 0f 1f 44 00 00 65 8b 05 ef f5 d5 10 83 f8 08 0f 83 b8 01 00 00 89 c0 48 0f a3 05 18 ad df 0d <73> 16 e8 61 16 09 00 84 c0 75 0d f6 05 93 b3 c9 0d 01 0f 84 d7 01
RSP: 0018:ffffc9000b676cf8 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8df3d8a0
RBP: ffffffff8173cf85 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc9000b676eb8 R11: ffffffff81acafb0 R12: 0000000000000002
R13: ffffffff8df3d8a0 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:165
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1395 [inline]
free_unref_folios+0xd22/0x1460 mm/page_alloc.c:3005
folios_put_refs+0x584/0x670 mm/swap.c:1002
free_pages_and_swap_cache+0x277/0x520 mm/swap_state.c:355
__tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:397 [inline]
tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404
zap_pte_range mm/memory.c:1894 [inline]
zap_pmd_range mm/memory.c:1947 [inline]
zap_pud_range mm/memory.c:1976 [inline]
zap_p4d_range mm/memory.c:1997 [inline]
unmap_page_range+0x3b37/0x4370 mm/memory.c:2018
unmap_single_vma mm/memory.c:2061 [inline]
unmap_vmas+0x399/0x580 mm/memory.c:2105
exit_mmap+0x240/0xb40 mm/mmap.c:1277
__mmput+0x118/0x430 kernel/fork.c:1133
exit_mm+0x1da/0x2c0 kernel/exit.c:580
do_exit+0x648/0x2300 kernel/exit.c:952
do_group_exit+0x21c/0x2d0 kernel/exit.c:1105
__do_sys_exit_group kernel/exit.c:1116 [inline]
__se_sys_exit_group kernel/exit.c:1114 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1114
x64_sys_call+0x21f7/0x2200 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3a3598efc9
RSP: 002b:00007ffcfe2f95a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3a3598efc9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffcfe2f960c R08: 00000019fe2f969f R09: 00000000000927c0
R10: 0000000000010764 R11: 0000000000000246 R12: 0000000000000045
R13: 00000000000927c0 R14: 000000000003d22a R15: 00007ffcfe2f9660
rcu: rcu_preempt kthread timer wakeup didn't happen for 10479 jiffies! g18977 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=1 timer-softirq=16385
rcu: rcu_preempt kthread starved for 10480 jiffies! g18977 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:27160 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5254 [inline]
__schedule+0x17c4/0x4d60 kernel/sched/core.c:6862
__schedule_loop kernel/sched/core.c:6944 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6959
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1300 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:__lock_acquire+0xff/0xd20 kernel/locking/lockdep.c:-1
Code: 8b b4 24 88 00 00 00 8b 6c 24 78 41 89 d5 48 c7 c1 70 63 1c 93 48 29 c8 48 c1 f8 03 48 be 29 5c 8f c2 f5 28 5c 8f 48 0f af f0 <45> 85 f6 0f 85 4a 01 00 00 45 85 ed 0f 84 41 01 00 00 41 83 fd 31
RSP: 0018:ffffc9000456f510 EFLAGS: 00000807
RAX: 0000000000000960 RBX: ffffffff99b43b38 RCX: ffffffff931c6370
RDX: 0000000000000002 RSI: 0000000000000060 RDI: ffff888028398000
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: dffffc0000000000 R11: fffffbfff1efacef R12: 0000000000000000
R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125fe5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30e0bff8 CR3: 000000000dd38000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
uart_port_ref_lock+0xc4/0x3b0 drivers/tty/serial/serial_core.c:83
uart_write+0x72/0x130 drivers/tty/serial/serial_core.c:624
handle_tx+0x23f/0x610 drivers/net/caif/caif_serial.c:222
__netdev_start_xmit include/linux/netdevice.h:5272 [inline]
netdev_start_xmit include/linux/netdevice.h:5281 [inline]
xmit_one net/core/dev.c:3853 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3869
__dev_queue_xmit+0x172a/0x3740 net/core/dev.c:4811
dev_queue_xmit include/linux/netdevice.h:3372 [inline]
tx+0x6b/0x190 drivers/block/aoe/aoenet.c:62
kthread+0x1d0/0x3e0 drivers/block/aoe/aoecmd.c:1241
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245