rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5819/1:b..l rcu: (detected by 0, t=10502 jiffies, g=35249, q=310 ncpus=2) task:syz-executor state:R running task stack:23272 pid:5819 tgid:5819 ppid:5805 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:55 [inline] RIP: 0010:unwind_next_frame+0x1632/0x20a0 arch/x86/kernel/unwind_orc.c:665 Code: fc ff df 48 8b 14 24 48 c1 ea 03 80 3c 02 00 0f 85 37 05 00 00 49 8d 7d 08 49 8b 5d 38 48 b8 00 00 00 00 00 fc ff df 48 89 fa <48> c1 ea 03 80 3c 02 00 0f 85 0a 05 00 00 49 8d 7d 10 49 8b 6d 08 RSP: 0018:ffffc9000428f868 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffffc9000428fd00 RCX: ffffc90004290000 RDX: ffffc9000428f8e0 RSI: ffffc9000428fcd0 RDI: ffffc9000428f8e0 RBP: 0000000000000000 R08: 0000000000000001 R09: 000000004f8bb13e R10: 0000000000000002 R11: 0000000000083c59 R12: ffffc9000428f928 R13: ffffc9000428f8d8 R14: ffffc9000428fd00 R15: ffffc9000428f90c arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556 slab_free_hook mm/slub.c:2501 [inline] slab_free mm/slub.c:6668 [inline] kmem_cache_free+0x15e/0x770 mm/slub.c:6779 sk_prot_free net/core/sock.c:2282 [inline] __sk_destruct+0x64c/0xbc0 net/core/sock.c:2384 sk_destruct+0xc2/0xf0 net/core/sock.c:2412 __sk_free+0xf4/0x3e0 net/core/sock.c:2423 sk_free+0x6a/0x90 net/core/sock.c:2434 sock_put include/net/sock.h:1998 [inline] tcp_close+0xd3/0x120 net/ipv4/tcp.c:3303 inet_release+0xed/0x200 net/ipv4/af_inet.c:437 __sock_release+0xb3/0x270 net/socket.c:662 sock_close+0x1c/0x30 net/socket.c:1455 __fput+0x402/0xb70 fs/file_table.c:468 fput_close_sync+0x118/0x260 fs/file_table.c:573 __do_sys_close fs/open.c:1573 [inline] __se_sys_close fs/open.c:1558 [inline] __x64_sys_close+0x8b/0x120 fs/open.c:1558 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f079a18e3aa RSP: 002b:00007ffdb099bf20 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f079a18e3aa RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007ffdb099bf7c R08: 00007ffdb099b86c R09: 0079746972756365 R10: 00007ffdb099b8d0 R11: 0000000000000293 R12: 0000000000000110 R13: 00000000000927c0 R14: 0000000000072dfa R15: 00007ffdb099bfd0 rcu: rcu_preempt kthread starved for 10535 jiffies! g35249 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:28064 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 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 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 36 60 02 c3 cc cc cc cc 0f 1f 00 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 13 e9 12 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6 RAX: 0000000001696399 RBX: 0000000000000001 RCX: ffffffff8b7776d9 RDX: 0000000000000000 RSI: ffffffff8dacb6cd RDI: ffffffff8bf2a580 RBP: ffffed1003b56498 R08: 0000000000000001 R09: ffffed10170a673d R10: ffff8880b85339eb R11: ffff88801dab2ff0 R12: 0000000000000001 R13: ffff88801dab24c0 R14: ffffffff90887cd0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249fd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000002f000 CR3: 0000000061424000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x148