rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=8b3c/1/0x4000000000000000 softirq=17120/17122 fqs=0
rcu: (detected by 0, t=10540 jiffies, g=10417, q=926 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:151 [inline]
RIP: 0010:lock_release+0x16a/0x2f0 kernel/locking/lockdep.c:5892
Code: 19 0f 84 00 01 00 00 48 c7 c7 e2 92 a0 8d e8 fd 3e ca 09 b8 ff ff ff ff 65 0f c1 05 68 b5 09 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
RSP: 0018:ffffc90000a08ce8 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffffff9ad08928 RCX: ffffc90000a08cfc
RDX: 0000000000000008 RSI: ffffffff8da092e2 RDI: ffffffff8bf082c0
RBP: 0000000000000002 R08: 0000000000000001 R09: fffff52000141198
R10: 0000000000000003 R11: 0000000000000001 R12: ffffffff84aea0fc
R13: 0000000000000002 R14: ffff88801d2b4900 R15: 0000000000000009
FS: 0000000000000000(0000) GS:ffff888124af6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005605ec343af8 CR3: 0000000075b9c000 CR4: 00000000003526f0
Call Trace:
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
_raw_spin_unlock_irqrestore+0x1a/0x80 kernel/locking/spinlock.c:194
debug_object_deactivate+0x1ec/0x3a0 lib/debugobjects.c:888
debug_hrtimer_deactivate kernel/time/hrtimer.c:443 [inline]
debug_deactivate kernel/time/hrtimer.c:483 [inline]
__run_hrtimer kernel/time/hrtimer.c:1745 [inline]
__hrtimer_run_queues+0x46f/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+0x10b/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:697
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xdfd/0x1600 kernel/smp.c:877
Code: 57 48 8b 54 24 10 4c 89 74 24 10 49 89 d5 48 89 d5 48 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 a5 4d 0c 00 f3 90 <41> 0f b6 45 00 40 38 c5 7c 08 84 c0 0f 85 e0 05 00 00 8b 43 08 31
RSP: 0018:ffffc90000116848 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8442840 RCX: ffffffff81b15581
RDX: ffff88801d2b4900 RSI: ffffffff81b1555b RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
R13: ffffed1017088509 R14: 0000000000000001 R15: 0000000000000000
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1043
__flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1381 [inline]
flush_tlb_mm_range+0x4a0/0x17a0 arch/x86/mm/tlb.c:1471
flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline]
ptep_clear_flush+0x136/0x180 mm/pgtable-generic.c:101
page_vma_mkclean_one.constprop.0+0x3b4/0x7e0 mm/rmap.c:1041
page_mkclean_one+0x196/0x260 mm/rmap.c:1082
__rmap_walk_file+0x359/0x620 mm/rmap.c:2918
rmap_walk_file+0x174/0x1f0 mm/rmap.c:2951
rmap_walk mm/rmap.c:2962 [inline]
folio_mkclean+0x251/0x3f0 mm/rmap.c:1114
folio_clear_dirty_for_io+0x153/0x790 mm/page-writeback.c:2932
mpage_submit_folio+0x84/0x2d0 fs/ext4/inode.c:2060
mpage_process_page_bufs+0x47c/0x8d0 fs/ext4/inode.c:2190
mpage_prepare_extent_to_map+0x765/0x14b0 fs/ext4/inode.c:2732
ext4_do_writepages+0xa11/0x3cf0 fs/ext4/inode.c:2873
ext4_writepages+0x37a/0x7d0 fs/ext4/inode.c:3021
do_writepages+0x27a/0x600 mm/page-writeback.c:2598
__writeback_single_inode+0x168/0x1570 fs/fs-writeback.c:1737
writeback_sb_inodes+0x72e/0x1d10 fs/fs-writeback.c:2030
__writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2107
wb_writeback+0x7f3/0xb70 fs/fs-writeback.c:2218
wb_check_old_data_flush fs/fs-writeback.c:2322 [inline]
wb_do_writeback fs/fs-writeback.c:2375 [inline]
wb_workfn+0x8ca/0xbe0 fs/fs-writeback.c:2403
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
process_scheduled_works kernel/workqueue.c:3346 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
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: rcu_preempt kthread starved for 10540 jiffies! g10417 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:28552 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: 0 UID: 0 PID: 6095 Comm: udevd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xdfd/0x1600 kernel/smp.c:877
Code: 57 48 8b 54 24 10 4c 89 74 24 10 49 89 d5 48 89 d5 48 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 a5 4d 0c 00 f3 90 <41> 0f b6 45 00 40 38 c5 7c 08 84 c0 0f 85 e0 05 00 00 8b 43 08 31
RSP: 0018:ffffc90003617920 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8540320 RCX: ffffffff81b15581
RDX: ffff888026570000 RSI: ffffffff81b1555b RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
R13: ffffed10170a8065 R14: 0000000000000001 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881249f6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005605ec30ebe0 CR3: 000000000e182000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1043
__flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1381 [inline]
flush_tlb_mm_range+0x4a0/0x17a0 arch/x86/mm/tlb.c:1471
tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline]
tlb_flush_mmu mm/mmu_gather.c:403 [inline]
tlb_finish_mmu+0x3c9/0x7c0 mm/mmu_gather.c:497
exit_mmap+0x3fc/0xb90 mm/mmap.c:1293
__mmput+0x12a/0x410 kernel/fork.c:1133
mmput+0x62/0x70 kernel/fork.c:1156
exit_mm kernel/exit.c:583 [inline]
do_exit+0x7c7/0x2bf0 kernel/exit.c:955
do_group_exit+0xd3/0x2a0 kernel/exit.c:1108
__do_sys_exit_group kernel/exit.c:1119 [inline]
__se_sys_exit_group kernel/exit.c:1117 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1117
x64_sys_call+0x151c/0x1740 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f41016f16c5
Code: Unable to access opcode bytes at 0x7f41016f169b.
RSP: 002b:00007ffda13e68a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00005605ec313280 RCX: 00007f41016f16c5
RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000
RBP: 00005605ec0d42c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffda13e68f0 R14: 0000000000000000 R15: 0000000000000000