rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6568/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=12081, q=544 ncpus=2)
task:syz.3.167 state:R running task stack:26504 pid:6568 tgid:6567 ppid:5825 task_flags:0x40054c flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
preempt_schedule_notrace+0x62/0xe0 kernel/sched/core.c:7206
preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:752
rcu_read_lock include/linux/rcupdate.h:842 [inline]
page_ext_get+0x7d/0x1a0 mm/page_ext.c:527
__reset_page_owner+0x2b/0x1a0 mm/page_owner.c:294
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+0x419/0x4e0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f63fe38eec9
RSP: 002b:00007f63ff2aa038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: fffffffffffffe00 RBX: 00007f63fe5e5fa0 RCX: 00007f63fe38eec9
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000006
RBP: 00007f63fe411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f63fe5e6038 R14: 00007f63fe5e5fa0 R15: 00007ffc878ff4b8
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g12081 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=7910
rcu: rcu_preempt kthread starved for 10502 jiffies! g12081 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:28232 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+0x3c2/0x780 kernel/kthread.c:463
ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148
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: 6579 Comm: syz.2.171 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0xd/0xc0 kernel/rcu/tree.c:751
Code: 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 53 65 ff 05 33 61 d9 11 fe 93 ab 09 48 c7 c3 a8 e2 7a 93 89 c5 83 f8 07 0f 87 82 00 00
RSP: 0018:ffffc90000007d30 EFLAGS: 00000007
RAX: 0000000000000000 RBX: ffffffff8e1c4120 RCX: ffffffff8966df37
RDX: ffff88802178c900 RSI: ffffffff8966dd5c RDI: ffffffff8e1c4120
RBP: ffff88814638f400 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8966dd5c
R13: 18716d8cc8000000 R14: 0000000000000002 R15: ffff888140fa9810
FS: 00007f43a7c206c0(0000) GS:ffff888124e85000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f54669156c0 CR3: 0000000049740000 CR4: 00000000003526f0
Call Trace:
trace_lock_release include/trace/events/lock.h:69 [inline]
lock_release+0x201/0x2f0 kernel/locking/lockdep.c:5879
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
advance_sched+0x6f1/0xc80 net/sched/sch_taprio.c:992
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x202/0xad0 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
__sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1058
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:check_preemption_disabled+0x0/0xe0 lib/smp_processor_id.c:13
Code: c0 75 0f 65 8b 05 9c 0c 2e 08 85 c0 74 04 90 0f 0b 90 e9 53 fc ff ff 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <41> 54 55 53 48 83 ec 08 65 8b 1d 15 ce 2d 08 65 8b 05 0a ce 2d 08
RSP: 0018:ffffc9001017f7e8 EFLAGS: 00000282
RAX: 0000000000000001 RBX: ffffea00015b9840 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff8bd01140 RDI: ffffffff8bd01180
RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff20be6b2
R10: ffffffff905f3597 R11: 0000000000000000 R12: 0000000000000001
R13: 0000200000e04000 R14: 0000000000000000 R15: ffffea00015b9870
rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
rcu_is_watching+0x12/0xc0 kernel/rcu/tree.c:751
rcu_read_unlock+0x26/0x60 include/linux/rcupdate.h:869
__folio_mod_stat+0x60/0x1f0 mm/rmap.c:1232
folio_add_new_anon_rmap+0x367/0x1dc0 mm/rmap.c:1592
do_anonymous_page mm/memory.c:5228 [inline]
do_pte_missing+0x2a89/0x3ba0 mm/memory.c:4359
handle_pte_fault mm/memory.c:6177 [inline]
__handle_mm_fault+0x1556/0x2aa0 mm/memory.c:6318
handle_mm_fault+0x589/0xd10 mm/memory.c:6487
faultin_page mm/gup.c:1126 [inline]
__get_user_pages+0x54e/0x3530 mm/gup.c:1428
populate_vma_page_range+0x267/0x3f0 mm/gup.c:1860
__mm_populate+0x1d8/0x380 mm/gup.c:1963
do_mlock+0x441/0x800 mm/mlock.c:653
__do_sys_mlock mm/mlock.c:661 [inline]
__se_sys_mlock mm/mlock.c:659 [inline]
__x64_sys_mlock+0x59/0x80 mm/mlock.c:659
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f43a6d8eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f43a7c20038 EFLAGS: 00000246 ORIG_RAX: 0000000000000095
RAX: ffffffffffffffda RBX: 00007f43a6fe5fa0 RCX: 00007f43a6d8eec9
RDX: 0000000000000000 RSI: 0000000000800000 RDI: 00002000007d8000
RBP: 00007f43a6e11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f43a6fe6038 R14: 00007f43a6fe5fa0 R15: 00007ffc1384a578