rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=254c/1/0x4000000000000000 softirq=58382/58383 fqs=351
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7231/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=43145, q=370 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 10049 Comm: syz.5.756 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:num_possible_cpus include/linux/cpumask.h:1222 [inline]
RIP: 0010:mm_get_cid kernel/sched/sched.h:3839 [inline]
RIP: 0010:sched_mm_cid_fork+0x576/0xc80 kernel/sched/core.c:10704
Code: e3 e9 64 ff ff ff 49 c7 c5 98 5e 1a 8e 49 c1 ed 03 eb 0b 44 89 e0 f7 d8 0f 81 2a fd ff ff f3 90 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 44 05 00 84 c0 75 50 44 8b 35 e1 d7 84 0c 48 89 ef 4c 89
RSP: 0018:ffffc90003ddfc78 EFLAGS: 00000887
RAX: dffffc0000000000 RBX: 0000000000000002 RCX: dffffc0000000000
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff888012758b90
RBP: ffff888012758b90 R08: 1ffff110024eb021 R09: 0000000000000000
R10: ffff88801275824c R11: fffff520007bbf80 R12: 0000000080000000
R13: 1ffffffff1c34bd3 R14: 0000000000000002 R15: ffff888012758000
FS: 00007f9f6307c6c0(0000) GS:ffff88812546a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff2987e8068 CR3: 0000000031767000 CR4: 0000000000350ef0
Call Trace:
bprm_execve+0xda1/0x1460 fs/exec.c:1771
do_execveat_common+0x50d/0x690 fs/exec.c:1846
__do_sys_execveat fs/exec.c:1941 [inline]
__se_sys_execveat fs/exec.c:1934 [inline]
__x64_sys_execveat+0xc7/0xf0 fs/exec.c:1934
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9f6219bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9f6307c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 00007f9f62416090 RCX: 00007f9f6219bf79
RDX: 0000000000000000 RSI: 0000200000000800 RDI: 0000000000000008
RBP: 00007f9f622327e0 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9f62416128 R14: 00007f9f62416090 R15: 00007ffec21e4938
task:udevd state:R running task stack:23584 pid:7231 tgid:7231 ppid:5185 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1585/0x5340 kernel/sched/core.c:6907
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234
irqentry_exit+0x599/0x620 kernel/entry/common.c:239
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:-1 [inline]
RIP: 0010:unwind_next_frame+0x1955/0x23c0 arch/x86/kernel/unwind_orc.c:680
Code: 51 fd b8 00 4d 8b 6e 08 4d 8d 7e 10 4c 89 f8 48 c1 e8 03 80 3c 28 00 74 08 4c 89 ff e8 34 fd b8 00 49 8b 07 4d 39 e5 0f 96 c1 <4c> 39 e0 0f 97 c2 20 ca 80 fa 01 0f 85 62 01 00 00 49 8d 4c 24 08
RSP: 0018:ffffc900051c7358 EFLAGS: 00000297
RAX: ffffc900051c8000 RBX: ffffffff914d7b01 RCX: 0000000000000001
RDX: ffffc900051c7468 RSI: dffffc0000000000 RDI: ffffc900051c7430
RBP: dffffc0000000000 R08: ffffc900051c7f38 R09: ffffc900051c7478
R10: dffffc0000000000 R11: fffff52000a38e91 R12: ffffc900051c7f48
R13: ffffc900051c0000 R14: ffffc900051c7428 R15: ffffc900051c7438
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
slab_free_hook mm/slub.c:2648 [inline]
slab_free mm/slub.c:6124 [inline]
kmem_cache_free+0x426/0x630 mm/slub.c:6254
__fput_deferred+0x2a3/0x380 fs/file_table.c:524
fput_close+0x11f/0x240 fs/file_table.c:586
path_openat+0x311d/0x3860 fs/namei.c:4839
do_file_open+0x23e/0x4a0 fs/namei.c:4859
do_sys_openat2+0x113/0x200 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2dec8a7407
RSP: 002b:00007ffc11c867b0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f2ded076880 RCX: 00007f2dec8a7407
RDX: 0000000000080000 RSI: 00007f2ded184f48 RDI: 000000000000000b
RBP: 000055efc53b1550 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000080000
R13: 00007f2ded184f48 R14: 0000000000000000 R15: 0000000000000009
rcu: rcu_preempt kthread starved for 9800 jiffies! g43145 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:27664 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1585/0x5340 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7004
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 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:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: 1e 6e 02 e9 8e 02 64 f5 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 43 1d 1d 00 fb f4 67 02 64 f5 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 00000242
RAX: 00000000010dc979 RBX: ffffffff819a77ad RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8deeea76 RDI: ffffffff8c279e80
RBP: ffffc90000197f10 R08: ffff8880b873395b R09: 1ffff110170e672b
R10: dffffc0000000000 R11: ffffed10170e672c R12: ffffffff90116eb0
R13: 1ffff11003ad9000 R14: 0000000000000001 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff88812556a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f841d0d1145 CR3: 0000000075c70000 CR4: 0000000000350ef0
Call Trace:
arch_safe_halt arch/x86/kernel/process.c:766 [inline]
default_idle+0x9/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1bd/0x500 kernel/sched/idle.c:332
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:430
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x147