rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-....: (1 GPs behind) idle=98b4/1/0x4000000000000000 softirq=117245/117246 fqs=2085 rcu: hardirqs softirqs csw/system rcu: number: 7577259 0 0 rcu: cputime: 20616 0 0 ==> 52500(ms) rcu: (detected by 0, t=10505 jiffies, g=155345, q=1242 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 28018 Comm: syz.1.5934 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:mark_lock+0xec/0x320 kernel/locking/lockdep.c:-1 Code: 06 02 00 00 83 3d f3 84 c3 15 00 74 36 45 31 ff 49 83 c7 60 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 f4 64 76 00 01 00 00 00 45 85 27 74 50 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 RSP: 0018:ffffc9000c6170c0 EFLAGS: 00000046 RAX: 1ffffffff2172400 RBX: ffff888022633c00 RCX: ffffffff8168df54 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff911bf600 RBP: 0000000000000002 R08: ffffffff911bf607 R09: 1ffffffff2237ec0 R10: dffffc0000000000 R11: fffffbfff2237ec1 R12: 0000000000000004 R13: dffffc0000000000 R14: ffff888022634708 R15: ffffffff90b92000 FS: 00007fac5bbf66c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fac5d9e9d40 CR3: 0000000043993000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000200000000300 DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: mark_held_locks kernel/locking/lockdep.c:4274 [inline] __trace_hardirqs_on_caller kernel/locking/lockdep.c:4292 [inline] lockdep_hardirqs_on_prepare+0x24d/0x770 kernel/locking/lockdep.c:4359 trace_hardirqs_on+0x28/0x40 kernel/trace/trace_preemptirq.c:61 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723 RIP: 0010:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5255 Code: 0f 84 33 01 00 00 48 85 db 0f 85 52 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 f0 b3 30 09 e8 fb 23 30 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:ffffc9000c617278 EFLAGS: 00000286 RAX: fe1931ddc3f11f00 RBX: 0000000000000000 RCX: fe1931ddc3f11f00 RDX: dffffc0000000000 RSI: ffffffff8acac900 RDI: ffffffff8b1c82e0 RBP: ffffc9000c6172d0 R08: ffffffff911bf607 R09: 1ffffffff2237ec0 R10: dffffc0000000000 R11: fffffbfff2237ec1 R12: ffff888022633c00 R13: dffffc0000000000 R14: ffff888022631e00 R15: ffff8880b8f3cac8 context_switch kernel/sched/core.c:5384 [inline] __schedule+0x155b/0x45a0 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 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:do_user_addr_fault+0x226/0x12c0 arch/x86/include/asm/irqflags.h:-1 Code: 02 00 00 31 ff e8 0a 21 4b 00 48 81 e3 00 02 00 00 75 07 e8 bc 1c 4b 00 eb 0b e8 b5 1c 4b 00 e8 80 8c 51 00 fb bb 14 02 00 00 <4c> 89 74 24 18 0f 1f 44 00 00 e8 9b 1c 4b 00 41 89 ee 41 83 e6 40 RSP: 0018:ffffc9000c617678 EFLAGS: 00000286 RAX: fe1931ddc3f11f00 RBX: 0000000000000214 RCX: fe1931ddc3f11f00 RDX: dffffc0000000000 RSI: ffffffff8acac900 RDI: ffffffff8b1c82e0 RBP: 0000000000000000 R08: ffffffff911bf607 R09: 1ffffffff2237ec0 R10: dffffc0000000000 R11: fffffbfff2237ec1 R12: ffffc9000c617768 R13: ffffc9000c6177f0 R14: ffff888025d88980 R15: ffff888022634140 handle_page_fault arch/x86/mm/fault.c:1463 [inline] exc_page_fault+0x64/0x100 arch/x86/mm/fault.c:1516 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:608 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:ffffc9000c617818 EFLAGS: 00050206 RAX: ffffffff84273701 RBX: 0000000000008000 RCX: 0000000000001140 RDX: 0000000000000001 RSI: 000020000077f000 RDI: ffff88807b136ec0 RBP: ffffc9000c617970 R08: ffff88807b137fff R09: 1ffff1100f626fff R10: dffffc0000000000 R11: ffffed100f627000 R12: ffff88807b130000 R13: 0000200000778140 R14: ffffc9000c617c18 R15: 1ffff920018c2f83 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+0x24e/0x12e0 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:2342 [inline] skb_copy_to_page_nocache include/net/sock.h:2368 [inline] kcm_sendmsg+0xd95/0x28b0 net/kcm/kcmsock.c:858 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] sock_write_iter+0x2df/0x420 net/socket.c:1160 call_write_iter include/linux/fs.h:2018 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x46c/0x990 fs/read_write.c:584 ksys_write+0x150/0x260 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fac5d99c629 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:00007fac5bbf6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fac5dc15fa0 RCX: 00007fac5d99c629 RDX: 00000000fffffdef RSI: 0000200000000140 RDI: 0000000000000008 RBP: 00007fac5da32b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fac5dc16038 R14: 00007fac5dc15fa0 R15: 00007fff8a2062e8