[syzbot] [net?] BUG: corrupted list in nsim_bpf_verifier_prep (2)

[syzbot <syzbot+530656d6f93f3af256f3@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    788bc43d8330 Merge branch 'microchip-lan865x-fix-probing-i..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=116cc242580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9c302bcfb26a48af
dashboard link: https://syzkaller.appspot.com/bug?extid=530656d6f93f3af256f3
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c958eee3370d/disk-788bc43d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/615040093399/vmlinux-788bc43d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/91377e9f5c93/bzImage-788bc43d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+530656d6f93f3af256f3@syzkaller.appspotmail.com

 slab kmalloc-64 start ffff888023c23980 pointer offset 40 size 64
list_add corruption. prev->next should be next (ffff88805628d3c0), but was ffff8880285b2a28. (prev=ffff888023c239a8).
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:34!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 12095 Comm: syz.2.1692 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__list_add_valid_or_report+0x123/0x130 lib/list_debug.c:32
Code: e8 a2 eb 31 fd 43 80 3c 2c 00 74 08 4c 89 f7 e8 83 df 52 fd 49 8b 16 48 c7 c7 40 3a e3 8b 48 89 de 4c 89 f1 e8 5e 65 57 fc 90 <0f> 0b 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000d1cf4a8 EFLAGS: 00010246
RAX: 0000000000000075 RBX: ffff88805628d3c0 RCX: b8e30b4d65b25b00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff1100ac51a79 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfa1ec R12: 1ffff11004784735
R13: dffffc0000000000 R14: ffff888023c239a8 R15: ffff8880285b24a8
FS:  00007fdac22936c0(0000) GS:ffff888125c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002400 CR3: 000000007459a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __list_add_valid include/linux/list.h:88 [inline]
 __list_add include/linux/list.h:150 [inline]
 list_add_tail include/linux/list.h:183 [inline]
 nsim_bpf_create_prog drivers/net/netdevsim/bpf.c:247 [inline]
 nsim_bpf_verifier_prep+0x397/0x530 drivers/net/netdevsim/bpf.c:262
 bpf_prog_offload_verifier_prep+0xd0/0x140 kernel/bpf/offload.c:305
 bpf_check+0x1cf6/0x1d2d0 kernel/bpf/verifier.c:24678
 bpf_prog_load+0x1318/0x1930 kernel/bpf/syscall.c:2979
 __sys_bpf+0x528/0x870 kernel/bpf/syscall.c:6029
 __do_sys_bpf kernel/bpf/syscall.c:6139 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6137 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6137
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdac138ebe9
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:00007fdac2293038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fdac15c6090 RCX: 00007fdac138ebe9
RDX: 0000000000000094 RSI: 0000200000000640 RDI: 0000000000000005
RBP: 00007fdac1411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdac15c6128 R14: 00007fdac15c6090 R15: 00007fff0483c898
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_add_valid_or_report+0x123/0x130 lib/list_debug.c:32
Code: e8 a2 eb 31 fd 43 80 3c 2c 00 74 08 4c 89 f7 e8 83 df 52 fd 49 8b 16 48 c7 c7 40 3a e3 8b 48 89 de 4c 89 f1 e8 5e 65 57 fc 90 <0f> 0b 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000d1cf4a8 EFLAGS: 00010246
RAX: 0000000000000075 RBX: ffff88805628d3c0 RCX: b8e30b4d65b25b00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 1ffff1100ac51a79 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfa1ec R12: 1ffff11004784735
R13: dffffc0000000000 R14: ffff888023c239a8 R15: ffff8880285b24a8
FS:  00007fdac22936c0(0000) GS:ffff888125d18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555873675c8 CR3: 000000007459a000 CR4: 00000000003526f0


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