rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9845/1:b..l rcu: (detected by 0, t=10502 jiffies, g=38393, q=216 ncpus=2) task:syz.7.919 state:R running task stack:28328 pid:9845 tgid:9844 ppid:8393 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:747 Code: c7 c7 60 ef 13 8e e8 5f 45 59 03 eb cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 41 56 53 65 ff 05 30 40 fa 10 e8 1b f1 d3 09 89 RSP: 0018:ffffc9000b7ef870 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff8222f8ce RCX: ffff88802da73c00 RDX: 0000000000000001 RSI: ffffffff8dba91df RDI: ffffffff8be33c00 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8172d195 R10: dffffc0000000000 R11: ffffffff81ac4b00 R12: 1ffff920016fdf29 R13: ffffc9000b7ef980 R14: ffffc9000b7ef948 R15: ffffffff8172d195 rcu_read_lock include/linux/rcupdate.h:842 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd4/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:330 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4191 [inline] slab_alloc_node mm/slub.c:4240 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4247 lsm_inode_alloc security/security.c:755 [inline] security_inode_alloc+0x39/0x330 security/security.c:1697 inode_init_always_gfp+0x9ed/0xdc0 fs/inode.c:306 inode_init_always include/linux/fs.h:3309 [inline] alloc_inode+0x82/0x1b0 fs/inode.c:353 new_inode_pseudo include/linux/fs.h:3392 [inline] sock_alloc net/socket.c:624 [inline] __sock_create+0x12d/0x9f0 net/socket.c:1553 sock_create net/socket.c:1647 [inline] __sys_socket_create net/socket.c:1684 [inline] __sys_socket+0xd7/0x1b0 net/socket.c:1731 __do_sys_socket net/socket.c:1745 [inline] __se_sys_socket net/socket.c:1743 [inline] __x64_sys_socket+0x7a/0x90 net/socket.c:1743 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: 0033:0x7f1813b8eba9 RSP: 002b:00007f1814a26fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f1813b8eba9 RDX: 0000000000000001 RSI: 0000000000000003 RDI: 000000000000001f RBP: 00007f1813c11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1813dd6038 R14: 00007f1813dd5fa0 R15: 00007ffd2b333c78 rcu: rcu_preempt kthread starved for 10108 jiffies! g38393 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:26896 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 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+0x439/0x7d0 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: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 3e fd 95 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 b3 e9 0d 00 f3 0f 1e fa fb f4 13 fd 95 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8de07d80 EFLAGS: 000002c2 RAX: 4180f0be10683c00 RBX: ffffffff819693f8 RCX: 4180f0be10683c00 RDX: 0000000000000001 RSI: ffffffff8d9b9b6e RDI: ffffffff8be33c00 RBP: ffffffff8de07eb8 R08: ffff8880b8632f9b R09: 1ffff110170c65f3 R10: dffffc0000000000 R11: ffffed10170c65f4 R12: ffffffff8fa3a430 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a20 FS: 0000000000000000(0000) GS:ffff888125c15000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb7d368de9c CR3: 00000000736d4000 CR4: 0000000000350ef0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:757 default_idle_call+0x74/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e8/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:744 start_kernel+0x3a9/0x410 init/main.c:1097 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288 common_startup_64+0x13e/0x147