rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=79585, q=241 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294998487-4294987985), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g79585 f0x2 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:28216 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x10e9/0x6820 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5273 Comm: dhcpcd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline] RIP: 0010:__lock_acquire+0x5f5/0x2630 kernel/locking/lockdep.c:5234 Code: 4c 24 10 44 8b 25 4b 69 f3 0e 45 85 e4 75 3c 85 c9 0f 85 b8 07 00 00 0f b7 43 20 66 25 ff 1f 0f b7 c0 48 0f a3 05 ab e5 2c 14 <0f> 83 35 0b 00 00 48 8d 04 80 48 8d 04 80 48 8d 04 c5 60 3b 11 96 RSP: 0018:ffffc90000007c40 EFLAGS: 00000047 RAX: 0000000000000000 RBX: ffff88802ac73108 RCX: 0000000000000003 RDX: 000000002cd708a8 RSI: 00000000e2f4bf9d RDI: 00000000c6b821bf RBP: ffff88802ac72500 R08: 00000000e3c36222 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000003 R15: cc889bfc2cd708a8 FS: 00007ffa19966780(0000) GS:ffff888124379000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fab7e617dac CR3: 0000000029186000 CR4: 00000000003526f0 Call Trace: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166 debug_object_deactivate+0x135/0x3b0 lib/debugobjects.c:890 debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline] __run_hrtimer kernel/time/hrtimer.c:1898 [inline] __hrtimer_run_queues+0x2f0/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__read_once_word_nocheck+0x3/0x10 include/asm-generic/rwonce.h:68 Code: ff ff 48 c7 c7 58 c2 ab 8b e8 69 92 be 00 e9 1e fa ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 8b 07 cc cc cc cc 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90003347350 EFLAGS: 00000202 RAX: ffffffff81000130 RBX: 0000000000000001 RCX: ffffffff922ab01e RDX: ffffc90003347f01 RSI: ffffc90003347f40 RDI: ffffc90003347f40 RBP: ffffc90003347410 R08: ffffffff922ab022 R09: 0000000000000007 R10: 0000000000000200 R11: 00000000000a8911 R12: ffffc90003347418 R13: ffffc900033473c8 R14: ffffc90003347f48 R15: ffffc900033473fc deref_stack_reg arch/x86/kernel/unwind_orc.c:422 [inline] unwind_next_frame+0xd07/0x2090 arch/x86/kernel/unwind_orc.c:614 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4905 avc_alloc_node+0x24/0x670 security/selinux/avc.c:498 avc_insert security/selinux/avc.c:618 [inline] avc_compute_av+0x101/0x820 security/selinux/avc.c:993 avc_perm_nonode+0xb1/0x180 security/selinux/avc.c:1117 avc_has_perm_noaudit+0x2d4/0x3b0 security/selinux/avc.c:1160 avc_has_perm+0xbd/0x1e0 security/selinux/avc.c:1195 selinux_socket_unix_may_send+0x1e6/0x2b0 security/selinux/hooks.c:5356 security_unix_may_send+0xc4/0x210 security/security.c:4175 unix_dgram_sendmsg+0xb38/0x1810 net/unix/af_unix.c:2248 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] __sys_sendto+0x468/0x4b0 net/socket.c:2265 __do_sys_sendto net/socket.c:2272 [inline] __se_sys_sendto net/socket.c:2268 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2268 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ffa199f0407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffca0911c40 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007ffa19966780 RCX: 00007ffa199f0407 RDX: 000000000000003f RSI: 00007ffca0911d80 RDI: 0000000000000003 RBP: 00007ffca09121b0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000202 R12: 00007ffca0912600 R13: 00007ffca0911d80 R14: 000000000000001d R15: 00007ffca0911d80