------------[ cut here ]------------ !atomic_long_inc_not_zero(&event->refcount) WARNING: kernel/events/core.c:10739 at __perf_event_overflow+0xb9e/0xec0 kernel/events/core.c:10739, CPU#0: syz.3.3289/18892 Modules linked in: CPU: 0 UID: 0 PID: 18892 Comm: syz.3.3289 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:__perf_event_overflow+0xb9e/0xec0 kernel/events/core.c:10739 Code: 08 37 00 4d 89 3e 4c 8b 7c 24 10 e9 c2 fc ff ff e8 27 c1 cc ff 49 bd 00 00 00 00 00 fc ff df e9 08 fe ff ff e8 13 c1 cc ff 90 <0f> 0b 90 e9 21 ff ff ff e8 05 c1 cc ff 48 c7 c7 40 1e d7 8b e8 e9 RSP: 0018:ffffc90005c574c0 EFLAGS: 00010287 RAX: ffffffff81f8cabd RBX: ffff88801aff9a20 RCX: 0000000000080000 RDX: ffffc9000f851000 RSI: 0000000000000192 RDI: 0000000000000193 RBP: ffffc90005c575d0 R08: ffff88801aff9b77 R09: 1ffff110035ff36e R10: dffffc0000000000 R11: ffffed10035ff36f R12: ffff88801aff9920 R13: dffffc0000000000 R14: ffff88801aff9b70 R15: 0000000000000000 FS: 00007f901cb706c0(0000) GS:ffff888125463000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000003417c000 CR4: 00000000003526f0 DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: perf_swevent_overflow kernel/events/core.c:10837 [inline] perf_swevent_event+0x323/0x650 kernel/events/core.c:-1 do_perf_sw_event kernel/events/core.c:10977 [inline] ___perf_sw_event+0x4a6/0x730 kernel/events/core.c:11004 __perf_sw_event+0xf9/0x1a0 kernel/events/core.c:11016 perf_sw_event include/linux/perf_event.h:1604 [inline] do_user_addr_fault+0x12a8/0x1340 arch/x86/mm/fault.c:1281 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:rep_movs_alternative+0x30/0x90 arch/x86/lib/copy_user_64.S:60 Code: 83 f9 08 73 25 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 c3 cc cc cc cc 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 db 83 f9 08 RSP: 0018:ffffc90005c57af8 EFLAGS: 00050206 RAX: 00007ffffffff001 RBX: 0000000000000038 RCX: 0000000000000038 RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffc90005c57b80 RBP: ffffc90005c57d90 R08: ffffc90005c57bb7 R09: 1ffff92000b8af76 R10: dffffc0000000000 R11: fffff52000b8af77 R12: ffffc90005c57de0 R13: 1ffff92000b8af6c R14: ffffc90005c57b80 R15: 0000000000000000 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:141 [inline] _inline_copy_from_user include/linux/uaccess.h:185 [inline] _copy_from_user+0x7a/0xb0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] copy_msghdr_from_user net/socket.c:2522 [inline] sendmsg_copy_msghdr net/socket.c:2623 [inline] ___sys_sendmsg+0x1c6/0x360 net/socket.c:2642 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f901bd9c799 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:00007f901cb70028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f901c015fa0 RCX: 00007f901bd9c799 RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 00007f901be32bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f901c016038 R14: 00007f901c015fa0 R15: 00007ffce14cf068 ---------------- Code disassembly (best guess): 0: 83 f9 08 cmp $0x8,%ecx 3: 73 25 jae 0x2a 5: 85 c9 test %ecx,%ecx 7: 74 0f je 0x18 9: 8a 06 mov (%rsi),%al b: 88 07 mov %al,(%rdi) d: 48 ff c7 inc %rdi 10: 48 ff c6 inc %rsi 13: 48 ff c9 dec %rcx 16: 75 f1 jne 0x9 18: c3 ret 19: cc int3 1a: cc int3 1b: cc int3 1c: cc int3 1d: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1) 24: 00 00 00 27: 0f 1f 00 nopl (%rax) * 2a: 48 8b 06 mov (%rsi),%rax <-- trapping instruction 2d: 48 89 07 mov %rax,(%rdi) 30: 48 83 c6 08 add $0x8,%rsi 34: 48 83 c7 08 add $0x8,%rdi 38: 83 e9 08 sub $0x8,%ecx 3b: 74 db je 0x18 3d: 83 f9 08 cmp $0x8,%ecx