rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (2 ticks this GP) idle=ab3c/1/0x4000000000000000 softirq=102007/102007 fqs=0
rcu: (detected by 0, t=10505 jiffies, g=93313, q=479 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5203 Comm: udevd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline]
RIP: 0010:lock_release+0x278/0x3b0 kernel/locking/lockdep.c:5891
Code: 89 f6 48 8b 54 24 18 e8 36 32 00 00 48 8b 5c 24 08 48 c7 c7 e6 20 95 8d e8 35 02 ab 09 b8 ff ff ff ff 65 0f c1 05 78 d7 d8 10 <83> f8 01 75 4d 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24
RSP: 0018:ffffc90000a08bf8 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 0000000000000002 RCX: ce7450190fc81e00
RDX: 0000000000000000 RSI: ffffffff8d9520e6 RDI: ffffffff8bbfc660
RBP: ffff88807cd966b0 R08: ffff88802484dc87 R09: 1ffff11004909b90
R10: dffffc0000000000 R11: ffffed1004909b91 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8880116212c0 R15: ffff88807cd95b80
FS: 00007fb65f1ab880(0000) GS:ffff8881261b1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fda37a3ff84 CR3: 000000003178a000 CR4: 00000000003526f0
Call Trace:
__raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
_raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
advance_sched+0x99f/0xc90 net/sched/sch_taprio.c:987
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x51c/0xc30 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x2a6/0x3b0 kernel/locking/lockdep.c:5893
Code: 4d 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 52 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 fa 92 d8 10 <48> 3b 44 24 28 75 75 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d c3
RSP: 0018:ffffc900030f7768 EFLAGS: 00000206
RAX: ce7450190fc81e00 RBX: 0000000000000202 RCX: ce7450190fc81e00
RDX: 0000000000000000 RSI: ffffffff8d9520e6 RDI: ffffffff8bbfc660
RBP: ffff88807cd966b0 R08: ffff88801ba801bf R09: 1ffff11003750037
R10: dffffc0000000000 R11: ffffed1003750038 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88801ba80220 R15: ffff88807cd95b80
up_read+0x16/0x20 kernel/locking/rwsem.c:1632
kernfs_iop_permission+0x308/0x430 fs/kernfs/inode.c:292
do_inode_permission fs/namei.c:526 [inline]
inode_permission+0x41f/0x5f0 fs/namei.c:596
lookup_inode_permission_may_exec fs/namei.c:636 [inline]
may_lookup fs/namei.c:1900 [inline]
link_path_walk+0xaad/0x18d0 fs/namei.c:2537
path_lookupat+0xe4/0x8c0 fs/namei.c:2745
filename_lookup+0x212/0x570 fs/namei.c:2775
vfs_statx+0xf8/0x550 fs/stat.c:353
vfs_fstatat+0x118/0x170 fs/stat.c:375
__do_sys_newfstatat fs/stat.c:542 [inline]
__se_sys_newfstatat fs/stat.c:536 [inline]
__x64_sys_newfstatat+0x116/0x190 fs/stat.c:536
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: 0033:0x7fb65eb11b0a
Code: 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 b9 f2 0d 00 f7
RSP: 002b:00007ffe86cdbf48 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 00007ffe86cdc3e0 RCX: 00007fb65eb11b0a
RDX: 00007ffe86cdbf50 RSI: 00007ffe86cdc3e0 RDI: 00000000ffffff9c
RBP: 000056432c0df910 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe86cdbfe0
R13: 00000000000000ff R14: 000056432ac1cbe0 R15: 00007ffe86cdcaa0
rcu: rcu_preempt kthread starved for 10505 jiffies! g93313 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:27136 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x14bc/0x5000 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: 21201 Comm: syz-executor 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+0xccf/0x12b0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 4a 94 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 f5 8f 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 d9 8f
RSP: 0018:ffffc9000b517560 EFLAGS: 00000293
RAX: ffffffff81b5ba87 RBX: 1ffff11017128101 RCX: ffff8880665a8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000b5176e0 R08: ffffffff8f805a77 R09: 1ffffffff1f00b4e
R10: dffffc0000000000 R11: fffffbfff1f00b4f R12: ffff8880b8940808
R13: dffffc0000000000 R14: ffff8880b883b9c0 R15: 0000000000000001
FS: 0000555562217500(0000) GS:ffff8881260b1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0f83d156c0 CR3: 0000000045e76000 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+0x1594/0x1b10 mm/mmap.c:1873
dup_mm kernel/fork.c:1486 [inline]
copy_mm+0x13c/0x4b0 kernel/fork.c:1538
copy_process+0x165d/0x3950 kernel/fork.c:2178
kernel_clone+0x21e/0x820 kernel/fork.c:2608
__do_sys_clone kernel/fork.c:2749 [inline]
__se_sys_clone kernel/fork.c:2733 [inline]
__x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2733
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: 0033:0x7f660ab85e93
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:00007ffe8bb88a78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f660ab85e93
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 00005555622177d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 000000000007d589 R15: 00007ffe8bb88c10