[syzbot] KASAN: vmalloc-out-of-bounds Read in __text_poke

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    e5313968c41b Merge branch 'Split bpf_sk_lookup remote_port..
git tree:       bpf-next
console output: https://syzkaller.appspot.com/x/log.txt?x=173474ac700000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c40b67275bfe2a58
dashboard link: https://syzkaller.appspot.com/bug?extid=ecb1e7e51c52f68f7481
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ecb1e7e51c52f68f7481@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: vmalloc-out-of-bounds in memcmp+0x16f/0x1c0 lib/string.c:770
Read of size 8 at addr ffffffffa0013400 by task syz-executor.3/26377

CPU: 1 PID: 26377 Comm: syz-executor.3 Not tainted 5.16.0-syzkaller-11655-ge5313968c41b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0xf/0x336 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 memcmp+0x16f/0x1c0 lib/string.c:770
 memcmp include/linux/fortify-string.h:269 [inline]
 __text_poke+0x5a2/0x8c0 arch/x86/kernel/alternative.c:1056
 text_poke_copy+0x66/0xa0 arch/x86/kernel/alternative.c:1132
 bpf_arch_text_copy+0x21/0x40 arch/x86/net/bpf_jit_comp.c:2426
 bpf_jit_binary_pack_finalize+0x43/0x170 kernel/bpf/core.c:1098
 bpf_int_jit_compile+0x9d5/0x12f0 arch/x86/net/bpf_jit_comp.c:2383
 bpf_prog_select_runtime+0x4d4/0x8a0 kernel/bpf/core.c:2163
 bpf_prog_load+0xfe6/0x2250 kernel/bpf/syscall.c:2349
 __sys_bpf+0x68a/0x59a0 kernel/bpf/syscall.c:4640
 __do_sys_bpf kernel/bpf/syscall.c:4744 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4742 [inline]
 __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:4742
 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+0x44/0xae
RIP: 0033:0x7f8a1c276059
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8a1abca168 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f8a1c389030 RCX: 00007f8a1c276059
RDX: 0000000000000064 RSI: 00000000202a0fb8 RDI: 0000000000000005
RBP: 00007f8a1c2d008d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe9ad17dff R14: 00007f8a1abca300 R15: 0000000000022000
 </TASK>


Memory state around the buggy address:
 ffffffffa0013300: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffffffa0013380: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffffffa0013400: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffffffa0013480: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffffffa0013500: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================


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