rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5945/1:b..l
rcu: (detected by 1, t=10516 jiffies, g=8893, q=734 ncpus=2)
task:syz-executor state:R running task stack:24056 pid:5945 tgid:5945 ppid:5940 task_flags:0x400140 flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7113
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
wp_page_copy mm/memory.c:3781 [inline]
do_wp_page+0x186d/0x52b0 mm/memory.c:4141
handle_pte_fault mm/memory.c:6211 [inline]
__handle_mm_fault+0x1ae3/0x2aa0 mm/memory.c:6336
handle_mm_fault+0x589/0xd10 mm/memory.c:6505
do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x64/0xc0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f05fe185c96
RSP: 002b:00007fffe94f0340 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000000 RCX: 00007f05fe185e13
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 000055555bb197d0 R11: 0000000000000246 R12: 0000000000000005
R13: ffffffffffffffa8 R14: 0000000000000006 R15: 00007fffe94f04d0
rcu: rcu_preempt kthread timer wakeup didn't happen for 6353 jiffies! g8893 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=5830
rcu: rcu_preempt kthread starved for 6354 jiffies! g8893 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: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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5959 Comm: udevd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:103 [inline]
RIP: 0010:do_raw_spin_unlock+0xdd/0x230 kernel/locking/spinlock_debug.c:141
Code: 85 d8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 6b 08 48 89 ea 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e ff 00 00 00 <65> 8b 05 b0 88 08 12 39 43 08 0f 85 b7 00 00 00 48 b8 00 00 00 00
RSP: 0000:ffffc90000007ce8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffffff9acf8b40 RCX: ffffffff819916f3
RDX: 1ffffffff359f169 RSI: 0000000000000004 RDI: ffffffff9acf8b40
RBP: ffffffff9acf8b48 R08: 0000000000000000 R09: fffffbfff359f168
R10: ffffffff9acf8b43 R11: ffffffff9acf8b40 R12: ffffffff9acf8b50
R13: ffff888030b4d340 R14: dffffc0000000000 R15: 1ffff92000000fa8
FS: 00007f6e30781880(0000) GS:ffff888124a06000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557ae50cffe8 CR3: 000000007d41b000 CR4: 00000000003526f0
Call Trace:
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline]
_raw_spin_unlock_irqrestore+0x22/0x80 kernel/locking/spinlock.c:194
debug_object_activate+0x2ec/0x4c0 lib/debugobjects.c:836
debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline]
debug_activate kernel/time/hrtimer.c:477 [inline]
enqueue_hrtimer+0x23/0x3b0 kernel/time/hrtimer.c:1081
__run_hrtimer kernel/time/hrtimer.c:1794 [inline]
__hrtimer_run_queues+0x8ff/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+0xe02/0x1600 kernel/smp.c:877
Code: 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 e5 0c 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 ff 83 e0 01 41
RSP: 0000:ffffc90003177898 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8540320 RCX: ffffffff81b0dc11
RDX: ffff88802bcf2480 RSI: ffffffff81b0dbeb RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
R13: ffffed10170a8065 R14: 0000000000000001 R15: 0000000000000001
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
wp_page_copy mm/memory.c:3746 [inline]
do_wp_page+0x1774/0x52b0 mm/memory.c:4141
handle_pte_fault mm/memory.c:6211 [inline]
__handle_mm_fault+0x1ae3/0x2aa0 mm/memory.c:6336
handle_mm_fault+0x589/0xd10 mm/memory.c:6505
do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x64/0xc0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f6e300b5db7
Code: 00 00 00 41 55 48 89 d0 49 89 fd 41 54 49 89 f4 53 4c 89 c3 48 83 ec 10 48 39 4f 60 0f 84 c1 00 00 00 42 f6 44 01 08 01 74 59 <48> 83 61 08 fe 48 3d ff 03 00 00 76 69 49 8b 55 70 49 8d 75 60 48
RSP: 002b:00007ffddb64e010 EFLAGS: 00010202
RAX: 0000000000006010 RBX: 00000000000001f0 RCX: 0000557ae50cffe0
RDX: 0000000000006010 RSI: 0000557ae50c9fd0 RDI: 00007f6e301f1ac0
RBP: 00007f6e301f1ac0 R08: 00000000000001f0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000557ae50c9fd0
R13: 00007f6e301f1ac0 R14: 00000000000001f0 R15: 00007f6e301f1ac0
sched: DL replenish lagged too much