rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (0 ticks this GP) idle=aeac/1/0x4000000000000000 softirq=0/0 fqs=0 rcuc=10506 jiffies(starved)
rcu: (detected by 0, t=10506 jiffies, g=44929, q=68 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 28 Comm: rcuc/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 e9 d1 3f 44 09 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 0c 0d 6f 0b 48 89 df 4c 89
RSP: 0018:ffffc90000a2fa28 EFLAGS: 00000887
RAX: 0000000080000000 RBX: ffff88807dd098d0 RCX: 1ffff11003ad167c
RDX: 0000000000000002 RSI: 0000000000000002 RDI: ffff88807dd098d0
RBP: 0000000080000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100fba12eb R12: dffffc0000000000
R13: 1ffffffff1a03099 R14: 0000000080000000 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff888126e06000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2f96db CR3: 000000008ae7e000 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+0x2153/0x50a0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
smpboot_thread_fn+0x5bd/0xa60 kernel/smpboot.c:156
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g44929 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=39205
rcu: rcu_preempt kthread starved for 10506 jiffies! g44929 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:21688 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1480/0x50a0 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+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5808 Comm: syz-executor 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+0xec1/0x12b0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 c8 9d 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 03 99 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 e7 98
RSP: 0018:ffffc90004d0f580 EFLAGS: 00000293
RAX: ffffffff81b4d959 RBX: 1ffff1101712854d RCX: ffff8880309fbc80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90004d0f700 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1db614f R12: ffff8880b8942a68
R13: dffffc0000000000 R14: ffff8880b883c8c0 R15: 0000000000000001
FS: 0000555570807500(0000) GS:ffff888126d06000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9d3d7456c0 CR3: 0000000038a5e000 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+0x6b1/0x1280 arch/x86/mm/tlb.c:1472
dup_mmap+0x1618/0x1b40 mm/mmap.c:1866
dup_mm kernel/fork.c:1529 [inline]
copy_mm+0x13c/0x4b0 kernel/fork.c:1581
copy_process+0x1665/0x3960 kernel/fork.c:2221
kernel_clone+0x21d/0x7a0 kernel/fork.c:2651
__do_sys_clone kernel/fork.c:2792 [inline]
__se_sys_clone kernel/fork.c:2776 [inline]
__x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2776
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9d3c9b5e93
Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00
RSP: 002b:00007fffb0862ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9d3c9b5e93
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 00005555708077d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 0000000000142b71 R15: 00007fffb0862e80
watchdog: BUG: soft lockup - CPU#0 stuck for 225s! [syz-executor:5808]
Modules linked in:
irq event stamp: 8529956
hardirqs last enabled at (8529955): [] irqentry_exit+0x5dd/0x660 kernel/entry/common.c:219
hardirqs last disabled at (8529956): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056
softirqs last enabled at (8478788): [] __local_bh_enable_ip+0x1b3/0x2e0 kernel/softirq.c:305
softirqs last disabled at (8478782): [] local_bh_disable include/linux/bottom_half.h:20 [inline]
softirqs last disabled at (8478782): [] spin_lock_bh include/linux/spinlock_rt.h:87 [inline]
softirqs last disabled at (8478782): [] release_sock+0x2f/0x210 net/core/sock.c:3793
CPU: 0 UID: 0 PID: 5808 Comm: syz-executor 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+0xec1/0x12b0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 c8 9d 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 03 99 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 e7 98
RSP: 0018:ffffc90004d0f580 EFLAGS: 00000293
RAX: ffffffff81b4d959 RBX: 1ffff1101712854d RCX: ffff8880309fbc80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90004d0f700 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1db614f R12: ffff8880b8942a68
R13: dffffc0000000000 R14: ffff8880b883c8c0 R15: 0000000000000001
FS: 0000555570807500(0000) GS:ffff888126d06000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9d3d7456c0 CR3: 0000000038a5e000 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+0x6b1/0x1280 arch/x86/mm/tlb.c:1472
dup_mmap+0x1618/0x1b40 mm/mmap.c:1866
dup_mm kernel/fork.c:1529 [inline]
copy_mm+0x13c/0x4b0 kernel/fork.c:1581
copy_process+0x1665/0x3960 kernel/fork.c:2221
kernel_clone+0x21d/0x7a0 kernel/fork.c:2651
__do_sys_clone kernel/fork.c:2792 [inline]
__se_sys_clone kernel/fork.c:2776 [inline]
__x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2776
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9d3c9b5e93
Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00
RSP: 002b:00007fffb0862ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9d3c9b5e93
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 00005555708077d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 0000000000142b71 R15: 00007fffb0862e80
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 28 Comm: rcuc/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:_find_first_zero_bit+0x4c/0xb0 lib/find_bit.c:149
Code: 48 89 f8 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 68 d0 a5 fd 49 8b 06 48 83 f8 ff 74 2b 45 31 ed 48 f7 d0 f3 48 0f bc c0 <4c> 01 e8 48 39 d8 48 0f 43 c3 eb 05 31 db 48 89 d8 5b 41 5c 41 5d
RSP: 0018:ffffc90000a2f9f8 EFLAGS: 00000002
RAX: 0000000000000002 RBX: 0000000000000002 RCX: 1ffff11003ad167c
RDX: 0000000000000002 RSI: 0000000000000002 RDI: ffff88807dd098d0
RBP: 0000000080000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100fba12eb R12: dffffc0000000000
R13: 0000000000000000 R14: ffff88807dd098d0 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff888126e06000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2f96db CR3: 000000008ae7e000 CR4: 00000000003526f0
Call Trace:
find_first_zero_bit include/linux/find.h:393 [inline]
__mm_get_cid kernel/sched/sched.h:3744 [inline]
mm_get_cid+0xc7/0x130 kernel/sched/sched.h:3759
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+0x2153/0x50a0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
smpboot_thread_fn+0x5bd/0xa60 kernel/smpboot.c:156
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246