rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (10500 ticks this GP) idle=afdc/1/0x4000000000000000 softirq=0/0 fqs=0 rcuc=10525 jiffies(starved)
rcu: (t=10500 jiffies g=20441 q=368 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 10499 jiffies! g20441 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=12768
rcu: rcu_preempt kthread starved for 10500 jiffies! g20441 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:27464 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x145f/0x5070 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
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+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
CPU: 0 UID: 0 PID: 9176 Comm: syz.3.1049 Not tainted syzkaller #0 PREEMPT_{RT,(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+0xe77/0x1250 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 12 9a 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 4d 95 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 31 95
RSP: 0018:ffffc900059c75e0 EFLAGS: 00000293
RAX: ffffffff81b414bf RBX: 1ffff1101712854d RCX: ffff888032a93c80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900059c7720 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1db666f R12: ffff8880b8942a68
R13: dffffc0000000000 R14: ffff8880b883c8c0 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888126cef000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe3af39dd58 CR3: 00000000336e2000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
__flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
flush_tlb_mm_range+0x60a/0x1170 arch/x86/mm/tlb.c:1472
tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403
tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
exit_mmap+0x439/0xb10 mm/mmap.c:1290
__mmput+0xcb/0x3d0 kernel/fork.c:1173
exit_mm+0x169/0x230 kernel/exit.c:581
do_exit+0x627/0x22f0 kernel/exit.c:959
do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
get_signal+0x125d/0x1310 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6eb598f749
Code: Unable to access opcode bytes at 0x7f6eb598f71f.
RSP: 002b:00007ffcc66995c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffdfc RBX: 000000000005f393 RCX: 00007f6eb598f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f6eb5be609c
RBP: 0000000000000032 R08: 3fffffffffffffff R09: 0000000bc66998bf
R10: 00007ffcc66996c0 R11: 0000000000000246 R12: 00007f6eb5be609c
R13: 00007ffcc66996c0 R14: 000000000005f3c5 R15: 00007ffcc66996e0
watchdog: BUG: soft lockup - CPU#0 stuck for 246s! [syz.3.1049:9176]
Modules linked in:
irq event stamp: 71414
hardirqs last enabled at (71413): [] irqentry_exit+0x5dd/0x660 kernel/entry/common.c:219
hardirqs last disabled at (71414): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056
softirqs last enabled at (0): [] rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
softirqs last enabled at (0): [] rcu_read_lock include/linux/rcupdate.h:867 [inline]
softirqs last enabled at (0): [] copy_process+0x915/0x3960 kernel/fork.c:2091
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 0 UID: 0 PID: 9176 Comm: syz.3.1049 Not tainted syzkaller #0 PREEMPT_{RT,(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+0xe7c/0x1250 kernel/smp.c:877
Code: 89 ee 83 e6 01 31 ff e8 12 9a 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 4d 95 0b 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 31 95 0b 00 eb e4 44
RSP: 0018:ffffc900059c75e0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff1101712854d RCX: ffff888032a93c80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900059c7720 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1db666f R12: ffff8880b8942a68
R13: dffffc0000000000 R14: ffff8880b883c8c0 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888126cef000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe3af39dd58 CR3: 00000000336e2000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
__flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
flush_tlb_mm_range+0x60a/0x1170 arch/x86/mm/tlb.c:1472
tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403
tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
exit_mmap+0x439/0xb10 mm/mmap.c:1290
__mmput+0xcb/0x3d0 kernel/fork.c:1173
exit_mm+0x169/0x230 kernel/exit.c:581
do_exit+0x627/0x22f0 kernel/exit.c:959
do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
get_signal+0x125d/0x1310 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6eb598f749
Code: Unable to access opcode bytes at 0x7f6eb598f71f.
RSP: 002b:00007ffcc66995c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffdfc RBX: 000000000005f393 RCX: 00007f6eb598f749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f6eb5be609c
RBP: 0000000000000032 R08: 3fffffffffffffff R09: 0000000bc66998bf
R10: 00007ffcc66996c0 R11: 0000000000000246 R12: 00007f6eb5be609c
R13: 00007ffcc66996c0 R14: 000000000005f3c5 R15: 00007ffcc66996e0
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:num_possible_cpus include/linux/cpumask.h:1222 [inline]
RIP: 0010:mm_get_cid+0xab/0x130 kernel/sched/sched.h:3759
Code: 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 49 c7 c5 c8 84 01 8d 49 c1 ed 03 bd 00 00 00 80 eb 07 44 89 f0 f7 d8 71 d4 f3 90 <43> 0f b6 44 25 00 84 c0 75 41 44 8b 3d 9c 8b 6f 0b 48 89 df 4c 89
RSP: 0018:ffffc900001d7be8 EFLAGS: 00000887
RAX: 0000000080000000 RBX: ffff888037f3e550 RCX: 1ffff11006552e0c
RDX: 0000000000000002 RSI: 0000000000000002 RDI: ffff888037f3e550
RBP: 0000000080000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1006fe7c7b R12: dffffc0000000000
R13: 1ffffffff1a03099 R14: 0000000080000000 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff888126def000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555582ec8588 CR3: 00000000336e2000 CR4: 00000000003526f0
Call Trace:
mm_cid_from_cpu kernel/sched/sched.h:3820 [inline]
mm_cid_schedin kernel/sched/sched.h:3870 [inline]
mm_cid_switch_to kernel/sched/sched.h:3886 [inline]
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x212a/0x5070 kernel/sched/core.c:6863
schedule_idle+0x52/0x90 kernel/sched/core.c:6986
do_idle+0x472/0x4d0 kernel/sched/idle.c:360
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x147