rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5850/1:b..l P5206/1:b..l P13175/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=56741, q=678 ncpus=2)
task:syz.3.2101 state:R running task stack:28424 pid:13175 tgid:13173 ppid:5834 task_flags:0x400040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5397 [inline]
__schedule+0x16aa/0x4c90 kernel/sched/core.c:6786
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7109
irqentry_exit+0x6f/0x90 kernel/entry/common.c:307
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:pid_nr_ns kernel/pid.c:494 [inline]
RIP: 0010:__task_pid_nr_ns+0x22d/0x470 kernel/pid.c:517
Code: 0f 84 a6 00 00 00 e8 02 fe 32 00 eb 05 e8 fb fd 32 00 48 85 db 74 55 4d 8d be 80 00 00 00 4c 89 f8 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 c5 01 00 00 45 8b 3f 4c 8d 63 04 4c 89 e0 48 c1 e8 03
RSP: 0018:ffffc90003e6fea8 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffff888079208900 RCX: ffff888026113c00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff818d25c8
R10: dffffc0000000000 R11: fffffbfff1f4165f R12: 0000000000000001
R13: dffffc0000000000 R14: ffff888024e5e000 R15: ffff888024e5e080
task_tgid_vnr include/linux/pid.h:294 [inline]
__ia32_sys_getpid+0x1e/0x30 kernel/sys.c:972
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff60b785967
RSP: 002b:00007ff60c616a48 EFLAGS: 00000206 ORIG_RAX: 0000000000000027
RAX: ffffffffffffffda RBX: 00007ff60c616bb0 RCX: 00007ff60b785967
RDX: 00007ff60c616a80 RSI: 00007ff60c616bb0 RDI: 0000000000000021
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ff60b9b6080 R15: 00007ffe37c55f98
task:udevd state:R running task stack:22928 pid:5206 tgid:5206 ppid:1 task_flags:0x400140 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5397 [inline]
__schedule+0x16aa/0x4c90 kernel/sched/core.c:6786
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7109
irqentry_exit+0x6f/0x90 kernel/entry/common.c:307
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_release+0x2b5/0x3e0 kernel/locking/lockdep.c:5896
Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 0b 43 fe 10 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90003027a10 EFLAGS: 00000206
RAX: 0d8eee97b736ce00 RBX: 0000000000000202 RCX: 0d8eee97b736ce00
RDX: 0000000000000000 RSI: ffffffff8db6fce0 RDI: ffffffff8be1ba00
RBP: ffff8880615746f0 R08: 0000000000000000 R09: ffffffff8259b5ac
R10: dffffc0000000000 R11: ffffffff8259f950 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff8e13f0e0 R15: ffff888061573c00
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
kernfs_root+0x1e5/0x230 fs/kernfs/kernfs-internal.h:80
kernfs_dop_revalidate+0x8c/0x5d0 fs/kernfs/dir.c:1179
d_revalidate fs/namei.c:929 [inline]
lookup_fast+0x250/0x5b0 fs/namei.c:-1
walk_component+0x55/0x400 fs/namei.c:2134
lookup_last fs/namei.c:2639 [inline]
path_lookupat+0x163/0x430 fs/namei.c:2663
filename_lookup+0x212/0x570 fs/namei.c:2692
do_readlinkat+0xd9/0x500 fs/stat.c:576
__do_sys_readlink fs/stat.c:613 [inline]
__se_sys_readlink fs/stat.c:610 [inline]
__x64_sys_readlink+0x7f/0x90 fs/stat.c:610
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff38fd153a7
RSP: 002b:00007ffe13a136c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007ffe13a13ba0 RCX: 00007ff38fd153a7
RDX: 0000000000000400 RSI: 00007ffe13a136d0 RDI: 00007ffe13a13ba0
RBP: 00007ffe13a136d0 R08: 00c0fcff00000000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000400
R13: 00005643cea28100 R14: 0000000000000000 R15: 00007ffe13a145d0
task:syz-executor state:R running task stack:20152 pid:5850 tgid:5850 ppid:5831 task_flags:0x400140 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5397 [inline]
__schedule+0x16aa/0x4c90 kernel/sched/core.c:6786
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6966
preempt_schedule+0xae/0xc0 kernel/sched/core.c:6990
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+0x3f/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
copy_pte_range mm/memory.c:1206 [inline]
copy_pmd_range+0x6727/0x7000 mm/memory.c:1267
copy_pud_range mm/memory.c:1304 [inline]
copy_p4d_range mm/memory.c:1328 [inline]
copy_page_range+0xc46/0x1270 mm/memory.c:1416
dup_mmap+0xf57/0x1ac0 mm/mmap.c:1838
dup_mm kernel/fork.c:1477 [inline]
copy_mm+0x13c/0x4b0 kernel/fork.c:1529
copy_process+0x16d3/0x3b80 kernel/fork.c:2169
kernel_clone+0x224/0x7f0 kernel/fork.c:2599
__do_sys_clone kernel/fork.c:2742 [inline]
__se_sys_clone kernel/fork.c:2726 [inline]
__x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2726
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffa9ff85213
RSP: 002b:00007ffcdcc1bd28 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ffa9ff85213
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 000055558a6067d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 00000000000d299c R15: 00007ffcdcc1bec0
rcu: rcu_preempt kthread starved for 10504 jiffies! g56741 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27224 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5397 [inline]
__schedule+0x16aa/0x4c90 kernel/sched/core.c:6786
__schedule_loop kernel/sched/core.c:6864 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6879
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
kthread+0x711/0x8a0 kernel/kthread.c:464
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.16.0-rc7-syzkaller-00018-g01a412d06bc5 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 53 de 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d d3 ad 21 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c2
RAX: c11705a858f38d00 RBX: ffffffff81976908 RCX: c11705a858f38d00
RDX: 0000000000000001 RSI: ffffffff8d982fe4 RDI: ffffffff8be1ba00
RBP: ffffc90000197f20 R08: ffff8880b8732f5b R09: 1ffff110170e65eb
R10: dffffc0000000000 R11: ffffed10170e65ec R12: ffffffff8fa0b2f0
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff11003a57b40
FS: 0000000000000000(0000) GS:ffff888125d57000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000000c0 CR3: 0000000077256000 CR4: 00000000003526f0
DR0: 000000000000004b DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:749
default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
cpuidle_idle_call kernel/sched/idle.c:185 [inline]
do_idle+0x1e8/0x510 kernel/sched/idle.c:325
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
common_startup_64+0x13e/0x147