rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=3224/1/0x4000000000000000 softirq=271624/271625 fqs=0
rcu: (detected by 1, t=10502 jiffies, g=340325, q=1741 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6967 Comm: rm Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:check_preemption_disabled+0x1d/0xe0 lib/smp_processor_id.c:53
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 53 65 8b 05 f7 0d 9c 07 65 8b 0d ec 0d 9c 07 f7 c1 ff ff ff 7f 74 0c 5b <41> 5e 41 5f 5d e9 49 e5 02 00 cc 9c 59 f7 c1 00 02 00 00 74 ea 65
RSP: 0018:ffffc90000007d38 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 0000000000000087 RCX: 0000000000010001
RDX: 0000000000000001 RSI: ffffffff8e4b26f2 RDI: ffffffff8c4bdc80
RBP: ffff8880203dc9c8 R08: ffff8880573da327 R09: 0000000000000000
R10: ffff8880573da318 R11: ffffed100ae7b465 R12: 0000000000000001
R13: 0000000000000001 R14: ffff8880b86281d8 R15: ffff8880203dbe00
FS: 0000000000000000(0000) GS:ffff888124f4e000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff4103df88 CR3: 0000000058e30000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00000000000004ff
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline]
lock_release+0x259/0x3c0 kernel/locking/lockdep.c:5891
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:176 [inline]
_raw_spin_unlock_irqrestore+0x1b/0x80 kernel/locking/spinlock.c:198
__run_hrtimer kernel/time/hrtimer.c:2028 [inline]
__hrtimer_run_queues+0x2bf/0xa10 kernel/time/hrtimer.c:2096
hrtimer_interrupt+0x448/0x910 kernel/time/hrtimer.c:2215
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:memset_orig+0x8a/0xb0 arch/x86/lib/memset_64.S:106
Code: 89 d1 83 e1 38 74 14 c1 e9 03 66 0f 1f 44 00 00 ff c9 48 89 07 48 8d 7f 08 75 f5 83 e2 07 74 0a ff ca 88 07 48 8d 7f 01 75 f6 <4c> 89 d0 e9 4e da 02 00 48 83 fa 07 76 e3 48 89 07 49 c7 c0 08 00
RSP: 0018:ffffc900058173d8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc900058174d8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900058174e8
RBP: 1ffffffff21fd676 R08: ffffc900058174e7 R09: 0000000000000000
R10: ffffc900058174d8 R11: fffff52000b02e9d R12: dffffc0000000000
R13: ffffffff90feb3b2 R14: ffffc90005817488 R15: ffffc900058174d0
unwind_next_frame+0xd04/0x2550 arch/x86/kernel/unwind_orc.c:621
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3159 [inline]
call_rcu+0xee/0x8b0 kernel/rcu/tree.c:3279
slab_free_hook mm/slub.c:2641 [inline]
slab_free mm/slub.c:6377 [inline]
kmem_cache_free+0x462/0x650 mm/slub.c:6504
__fput_deferred+0x2a3/0x380 fs/file_table.c:567
fput_close+0x11f/0x240 fs/file_table.c:629
path_openat+0x30b9/0x3830 fs/namei.c:4872
do_file_open+0x23e/0x4a0 fs/namei.c:4892
do_sys_openat2+0x115/0x200 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_sys_openat fs/open.c:1390 [inline]
__se_sys_openat fs/open.c:1385 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1385
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb9dd7c40ba
Code: 41 89 f2 48 89 54 24 e0 41 83 e2 40 75 2a 89 f0 f7 d0 a9 00 00 41 00 74 1f 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 77 2e c3 0f 1f 44 00 00 48 8d 44 24 08 c7 44 24
RSP: 002b:00007fff4103de68 EFLAGS: 00000206 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fff4103dee0 RCX: 00007fb9dd7c40ba
RDX: 0000000000080000 RSI: 00007fff4103dee0 RDI: 00000000ffffff9c
RBP: 00007fff4103ded0 R08: 00007fff4103e0d7 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000033
R13: 00007fb9dd798000 R14: 00007fff4103e0f0 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10502 jiffies! g340325 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 24023 Comm: kworker/u8:37 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x11e6/0x15f0 kernel/smp.c:912
Code: c0 75 7a 41 8b 1e 89 de 83 e6 01 31 ff e8 e2 22 0c 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 8e 1e 0c 00 eb 37 f3 90 <41> 0f b6 04 1c 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 73 1e 0c
RSP: 0000:ffffc90003f9e240 EFLAGS: 00000293
RAX: ffffffff81bae58d RBX: dffffc0000000000 RCX: ffff88801e755d00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003f9e390 R08: ffff888035f80c07 R09: 1ffff11006bf0180
R10: dffffc0000000000 R11: ffffffff817973f0 R12: 1ffff110170c85fd
R13: ffff8880b873c448 R14: ffff8880b8642fe8 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88812504e000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f516e53a CR3: 000000007f3dc000 CR4: 00000000003526f0
DR0: 0000000000007fff DR1: 0000000000000000 DR2: 0000000000000007
DR3: 0000000000000004 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1077
__flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
flush_tlb_mm_range+0x5c4/0x1090 arch/x86/mm/tlb.c:1451
flush_tlb_page arch/x86/include/asm/tlbflush.h:345 [inline]
ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:104
page_vma_mkclean_one+0x43f/0x780 mm/rmap.c:1138
page_mkclean_one+0x1d8/0x2b0 mm/rmap.c:1186
__rmap_walk_file+0x450/0x610 mm/rmap.c:3064
rmap_walk mm/rmap.c:3108 [inline]
folio_mkclean+0x2d5/0x3f0 mm/rmap.c:1218
folio_clear_dirty_for_io+0x190/0x820 mm/page-writeback.c:2909
mpage_submit_folio+0x83/0x2a0 fs/ext4/inode.c:2085
mpage_process_page_bufs+0x6b2/0x8c0 fs/ext4/inode.c:2215
mpage_prepare_extent_to_map+0xe0e/0x1690 fs/ext4/inode.c:2754
ext4_do_writepages+0xc36/0x47a0 fs/ext4/inode.c:2895
ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3043
do_writepages+0x338/0x560 mm/page-writeback.c:2571
__writeback_single_inode+0x12e/0xf90 fs/fs-writeback.c:1787
writeback_sb_inodes+0x9de/0x1b00 fs/fs-writeback.c:2079
__writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2155
wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2266
wb_check_old_data_flush fs/fs-writeback.c:2370 [inline]
wb_do_writeback fs/fs-writeback.c:2449 [inline]
wb_workfn+0xc92/0x10f0 fs/fs-writeback.c:2477
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245