rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-....: (1 GPs behind) idle=e7e4/1/0x4000000000000000 softirq=13672/13673 fqs=5236 rcu: hardirqs softirqs csw/system rcu: number: 14910510 0 0 rcu: cputime: 6271 46246 0 ==> 52500(ms) rcu: (detected by 1, t=10502 jiffies, g=12221, q=2115 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6159 Comm: syz.0.87 Not tainted 6.6.102-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:asm_sysvec_irq_work+0x0/0x20 arch/x86/include/asm/idtentry.h:723 Code: 06 25 ed ff e9 a1 03 00 00 90 f3 0f 1e fa 0f 01 ca fc 6a ff e8 a1 02 00 00 48 89 c4 48 89 e7 e8 f6 06 ed ff e9 81 03 00 00 90 0f 1e fa 0f 01 ca fc 6a ff e8 81 02 00 00 48 89 c4 48 89 e7 e8 RSP: 0018:ffffc90000007e18 EFLAGS: 00000086 RAX: 76c18762dc806600 RBX: 0000000000000200 RCX: 76c18762dc806600 RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0 RBP: ffffc90000007f50 R08: ffffffff90da3537 R09: 1ffffffff21b46a6 R10: dffffc0000000000 R11: fffffbfff21b46a7 R12: 000000000000000a R13: 0000000000000000 R14: ffffffff8ca0a0c0 R15: ffff88801aff1e00 FS: 00007f34add3c6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000b3000 CR3: 000000005ed6a000 CR4: 00000000003506f0 Call Trace: RIP: 0010:variable_ffs arch/x86/include/asm/bitops.h:319 [inline] RIP: 0010:handle_softirqs+0x1b0/0x820 kernel/softirq.c:566 Code: 89 64 24 2c 0f b7 db 48 c7 c7 a0 b2 a9 8a e8 57 c8 1b 09 65 66 c7 05 fd 23 b2 7e 00 00 e8 18 58 3a 00 fb 49 c7 c6 c0 a0 a0 8c <89> 5c 24 34 b8 ff ff ff ff 0f bc 44 24 34 41 89 c5 41 ff c5 0f 84 RSP: 0018:ffffc90000007e40 EFLAGS: 00000286 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 39 58 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc9000b43efc0 EFLAGS: 00000206 RAX: 76c18762dc806600 RBX: 1ffff92001687e00 RCX: 76c18762dc806600 RDX: dffffc0000000000 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0 RBP: ffffc9000b43f0c0 R08: ffffffff90da3537 R09: 1ffffffff21b46a6 R10: dffffc0000000000 R11: fffffbfff21b46a7 R12: ffffffff8cd35400 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock include/linux/rcupdate.h:818 [inline] do_perf_sw_event kernel/events/core.c:9937 [inline] ___perf_sw_event+0x63a/0x6f0 kernel/events/core.c:9965 __perf_sw_event+0x139/0x270 kernel/events/core.c:9977 perf_sw_event include/linux/perf_event.h:1442 [inline] mm_account_fault mm/memory.c:-1 [inline] handle_mm_fault+0x4121/0x4920 mm/memory.c:5347 do_user_addr_fault+0x738/0x12e0 arch/x86/mm/fault.c:1373 handle_page_fault arch/x86/mm/fault.c:1465 [inline] exc_page_fault+0x67/0x110 arch/x86/mm/fault.c:1521 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:ffffc9000b43f718 EFLAGS: 00050206 RAX: ffffffff841bfa01 RBX: 1ffff92001687fc7 RCX: 000000000000e9c0 RDX: 0000000000000000 RSI: ffff888077e218f8 RDI: 00002000000b3000 RBP: ffffc9000b43f878 R08: ffff888077e302b7 R09: 1ffff1100efc6056 R10: dffffc0000000000 R11: ffffed100efc6057 R12: ffff888077e200e8 R13: 00000000000101d0 R14: 00000000000101d0 R15: ffffc9000b43fe48 copy_user_generic arch/x86/include/asm/uaccess_64.h:112 [inline] raw_copy_to_user arch/x86/include/asm/uaccess_64.h:133 [inline] copyout lib/iov_iter.c:168 [inline] _copy_to_iter+0x249/0x10d0 lib/iov_iter.c:316 __skb_datagram_iter+0xdb/0x780 net/core/datagram.c:419 skb_copy_datagram_iter+0xb1/0x200 net/core/datagram.c:535 skb_copy_datagram_msg include/linux/skbuff.h:4014 [inline] tipc_recvstream+0x72b/0xe70 net/tipc/socket.c:2072 sock_recvmsg_nosec net/socket.c:1046 [inline] sock_recvmsg net/socket.c:1068 [inline] ____sys_recvmsg+0x29e/0x5b0 net/socket.c:2814 ___sys_recvmsg+0x1b6/0x510 net/socket.c:2856 __sys_recvmsg net/socket.c:2886 [inline] __do_sys_recvmsg net/socket.c:2896 [inline] __se_sys_recvmsg net/socket.c:2893 [inline] __x64_sys_recvmsg+0x1f2/0x2c0 net/socket.c:2893 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: 0033:0x7f34acf8ebe9 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:00007f34add3c038 EFLAGS: 00000246 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 00007f34ad1b5fa0 RCX: 00007f34acf8ebe9 RDX: 0000000000001f00 RSI: 0000200000000500 RDI: 000000000000000c RBP: 00007f34ad011e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f34ad1b6038 R14: 00007f34ad1b5fa0 R15: 00007ffe3c063668