rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P27347/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=136849, q=289 ncpus=2)
task:syz.7.5272 state:R running task stack:27272 pid:27347 tgid:27347 ppid:14922 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:rcu_is_watching+0x67/0xb0 kernel/rcu/tree.c:752
Code: 89 f7 e8 2c 61 7f 00 48 c7 c3 d8 7f 94 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d e9 8e ec 10 <74> 11 83 e0 04 c1 e8 02 5b 41 5e 41 5f e9 47 14 ad 09 cc e8 01 b7
RSP: 0018:ffffc9000deff218 EFLAGS: 00000286
RAX: 0000000001064d8c RBX: ffff8880b8732fd8 RCX: 4c2dd36655388a00
RDX: 0000000000000000 RSI: ffffffff8bc0de40 RDI: ffffffff8bc0de00
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8173df15
R10: ffffc9000deff358 R11: ffffffff81ac9fe0 R12: 1ffff92001bdfe61
R13: ffffc9000deff340 R14: ffffffff8da67dd8 R15: dffffc0000000000
rcu_read_lock include/linux/rcupdate.h:868 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xd4/0x2390 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
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3123 [inline]
call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3243
slab_free_hook mm/slub.c:2494 [inline]
slab_free mm/slub.c:6619 [inline]
kmem_cache_free+0x4b5/0x690 mm/slub.c:6729
anon_vma_free mm/rmap.c:136 [inline]
__put_anon_vma+0x12b/0x2d0 mm/rmap.c:2773
put_anon_vma include/linux/rmap.h:117 [inline]
unlink_anon_vmas+0x503/0x670 mm/rmap.c:443
free_pgtables+0x72b/0x9c0 mm/memory.c:413
exit_mmap+0x43c/0xb40 mm/mmap.c:1288
__mmput+0x118/0x430 kernel/fork.c:1133
exit_mm+0x1da/0x2c0 kernel/exit.c:582
do_exit+0x648/0x2300 kernel/exit.c:954
do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
__do_sys_exit_group kernel/exit.c:1118 [inline]
__se_sys_exit_group kernel/exit.c:1116 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1116
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: 0033:0x7f3d8418efc9
RSP: 002b:00007ffef349f2e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3d8418efc9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffef349f34c R08: 00000003f349f3df R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 000000000000021c
R13: 00000000000927c0 R14: 00000000000e3596 R15: 00007ffef349f3a0
rcu: rcu_preempt kthread timer wakeup didn't happen for 10548 jiffies! g136849 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=57324
rcu: rcu_preempt kthread starved for 10549 jiffies! g136849 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:27128 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 1301 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:do_raw_spin_lock+0x0/0x290 kernel/locking/spinlock_debug.c:114
Code: ff 89 d9 80 e1 07 80 c1 03 38 c1 7c 90 48 89 df e8 f5 ba 87 00 eb 86 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48
RSP: 0018:ffffc900049ff638 EFLAGS: 00000092
RAX: b1f3ee68c37b8f00 RBX: ffffffff99d3db80 RCX: b1f3ee68c37b8f00
RDX: 0000000000000000 RSI: ffffffff8da2edcf RDI: ffffffff99d3db80
RBP: ffffc900049ff6c0 R08: 0000000000000000 R09: ffffffff851b4c34
R10: dffffc0000000000 R11: fffffbfff1f3d4ef R12: dffffc0000000000
R13: dffffc0000000000 R14: 0000000000000a02 R15: 1ffff9200093fec8
FS: 0000000000000000(0000) GS:ffff888125ceb000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f41f6d156c0 CR3: 000000002f692000 CR4: 00000000003526f0
DR0: fffffffffffffff1 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
_raw_spin_lock_irqsave+0xb3/0xf0 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:5259 [inline]
netdev_start_xmit include/linux/netdevice.h:5268 [inline]
xmit_one net/core/dev.c:3845 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3861
__dev_queue_xmit+0x172a/0x3740 net/core/dev.c:4803
dev_queue_xmit include/linux/netdevice.h:3368 [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