Re: [syzbot] kernel BUG in __text_poke

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    d28b25a62a47 selftests/net: fix section name when using xd..
git tree:       bpf
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11582697f00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=833001d0819ddbc9
dashboard link: https://syzkaller.appspot.com/bug?extid=87f65c75f4a72db05445
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14281c84080000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=102d6448080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+87f65c75f4a72db05445@xxxxxxxxxxxxxxxxxxxxxxxxx

------------[ cut here ]------------
kernel BUG at arch/x86/kernel/alternative.c:1041!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 3688 Comm: syz-executor292 Not tainted 5.19.0-rc4-syzkaller-00118-gd28b25a62a47 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
RIP: 0010:__text_poke+0x348/0x8e0 arch/x86/kernel/alternative.c:1041
Code: c3 0f 86 2c fe ff ff 49 8d bc 24 00 10 00 00 e8 6e 6b 8d 00 48 89 44 24 30 48 85 db 74 0c 48 83 7c 24 30 00 0f 85 1b fe ff ff <0f> 0b 48 b8 00 f0 ff ff ff ff 0f 00 49 21 c0 48 85 db 0f 85 bf 02
RSP: 0018:ffffc900032cf540 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888018503b00 RSI: ffffffff81b97e83 RDI: 0000000000000005
RBP: 0000000000000004 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffffffffa0000fc0
R13: 0000000000000004 R14: 0000000000000fc4 R15: 0000000000002000
FS:  0000555556bcb300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002000cf3d CR3: 000000001d6a5000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 text_poke_copy+0x6d/0xa0 arch/x86/kernel/alternative.c:1186
 bpf_arch_text_copy+0x21/0x40 arch/x86/net/bpf_jit_comp.c:2491
 bpf_jit_binary_pack_alloc+0x8fd/0x990 kernel/bpf/core.c:1118
 bpf_int_jit_compile+0x53a/0x13e0 arch/x86/net/bpf_jit_comp.c:2422
 jit_subprogs kernel/bpf/verifier.c:13562 [inline]
 fixup_call_args kernel/bpf/verifier.c:13693 [inline]
 bpf_check+0x6e45/0xbbc0 kernel/bpf/verifier.c:15044
 bpf_prog_load+0xfb2/0x2250 kernel/bpf/syscall.c:2575
 __sys_bpf+0x11a1/0x5700 kernel/bpf/syscall.c:4917
 __do_sys_bpf kernel/bpf/syscall.c:5021 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5019 [inline]
 __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:5019
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7fe82c3681f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe743b9ed8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fe82c3681f9
RDX: 0000000000000070 RSI: 0000000020000440 RDI: 0000000000000005
RBP: 00007ffe743b9ef0 R08: 0000000000000002 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__text_poke+0x348/0x8e0 arch/x86/kernel/alternative.c:1041
Code: c3 0f 86 2c fe ff ff 49 8d bc 24 00 10 00 00 e8 6e 6b 8d 00 48 89 44 24 30 48 85 db 74 0c 48 83 7c 24 30 00 0f 85 1b fe ff ff <0f> 0b 48 b8 00 f0 ff ff ff ff 0f 00 49 21 c0 48 85 db 0f 85 bf 02
RSP: 0018:ffffc900032cf540 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888018503b00 RSI: ffffffff81b97e83 RDI: 0000000000000005
RBP: 0000000000000004 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffffffffa0000fc0
R13: 0000000000000004 R14: 0000000000000fc4 R15: 0000000000002000
FS:  0000555556bcb300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002000cf3d CR3: 000000001d6a5000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400