rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-....: (1 GPs behind) idle=1ce4/1/0x4000000000000000 softirq=39454/39455 fqs=5250 rcu: hardirqs softirqs csw/system rcu: number: 11374883 0 0 rcu: cputime: 24742 0 0 ==> 52510(ms) rcu: (detected by 0, t=10502 jiffies, g=49829, q=846 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 12275 Comm: syz.7.2412 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:native_apic_msr_eoi+0xf/0x10 arch/x86/include/asm/apic.h:202 Code: c3 89 c6 89 da 48 c7 c7 a0 8b b9 8c 89 c5 e8 48 76 18 03 89 e8 eb e3 0f 1f 40 00 f3 0f 1e fa b9 0b 08 00 00 31 c0 31 d2 0f 30 f3 0f 1e fa 81 ff cf 00 00 00 7f 0c 83 ff 20 74 2a 83 ff 30 74 RSP: 0018:ffffc900001f0fd8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffffc9000510f388 RCX: 000000000000080b RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc9000510f388 RBP: 0000000000000000 R08: ffffffff8e4a8d6f R09: 1ffffffff1c951ad R10: dffffc0000000000 R11: ffffc900001f0ff8 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f471d88a6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c310d50 CR3: 0000000079278000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: apic_eoi arch/x86/include/asm/apic.h:409 [inline] __sysvec_irq_work+0x11/0x380 arch/x86/kernel/irq_work.c:19 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0x9c/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723 RIP: 0010:finish_task_switch+0x26a/0x920 kernel/sched/core.c:5254 Code: 0f 84 37 01 00 00 48 85 db 0f 85 56 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 70 25 1c 09 e8 1b a3 2f 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffc9000510f438 EFLAGS: 00000282 RAX: 11b7c9d49e74e400 RBX: 0000000000000000 RCX: 11b7c9d49e74e400 RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6b00 RBP: ffffc9000510f490 R08: ffffffff90da860f R09: 1ffffffff21b50c1 R10: dffffc0000000000 R11: fffffbfff21b50c2 R12: ffff88802fdbda00 R13: dffffc0000000000 R14: ffff88802abe1e00 R15: ffff8880b8f3ccc8 context_switch kernel/sched/core.c:5383 [inline] __schedule+0x14da/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:rep_movs_alternative+0x4a/0x90 arch/x86/lib/copy_user_64.S:71 Code: 75 f1 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb c9 a4 c3 48 8b 06 48 89 07 48 8d 47 08 48 83 e0 f8 48 29 f8 48 01 RSP: 0018:ffffc9000510f818 EFLAGS: 00050206 RAX: ffffffff841cdf01 RBX: 0000000000008000 RCX: 0000000000007140 RDX: 0000000000000001 RSI: 0000200000759000 RDI: ffff8880617f8ec0 RBP: ffffc9000510f970 R08: ffff8880617fffff R09: 1ffff1100c2fffff R10: dffffc0000000000 R11: ffffed100c300000 R12: ffff8880617f8000 R13: 0000200000758140 R14: ffffc9000510fc18 R15: 1ffff92000a21f83 copy_user_generic arch/x86/include/asm/uaccess_64.h:112 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:127 [inline] copyin lib/iov_iter.c:193 [inline] _copy_from_iter+0x248/0x1290 lib/iov_iter.c:390 copy_from_iter include/linux/uio.h:209 [inline] copy_from_iter_full include/linux/uio.h:216 [inline] skb_do_copy_data_nocache include/net/sock.h:2329 [inline] skb_copy_to_page_nocache include/net/sock.h:2355 [inline] kcm_sendmsg+0xd87/0x2880 net/kcm/kcmsock.c:858 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] sock_write_iter+0x2bb/0x3f0 net/socket.c:1160 call_write_iter include/linux/fs.h:2018 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x43b/0x940 fs/read_write.c:584 ksys_write+0x147/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f471c98f6c9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f471d88a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f471cbe5fa0 RCX: 00007f471c98f6c9 RDX: 00000000fffffdef RSI: 0000200000000140 RDI: 0000000000000005 RBP: 00007f471ca11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f471cbe6038 R14: 00007f471cbe5fa0 R15: 00007ffe2178c3b8