From: syzbot ci <syzbot+ciad93e439a86bd2a7@syzkaller.appspotmail.com>
To: andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org,
daniel@iogearbox.net, eddyz87@gmail.com, haoluo@google.com,
john.fastabend@gmail.com, jolsa@kernel.org, kpsingh@kernel.org,
martin.lau@linux.dev, sdf@fomichev.me, shenghaoyuan0928@163.com,
song@kernel.org, tangyazhou518@outlook.com,
tangyazhou@zju.edu.cn, yonghong.song@linux.dev, ziye@zju.edu.cn
Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com
Subject: [syzbot ci] Re: bpf: Add value tracking for BPF_DIV
Date: Tue, 23 Dec 2025 05:50:21 -0800 [thread overview]
Message-ID: <694a9e1d.050a0220.19928e.0028.GAE@google.com> (raw)
In-Reply-To: <20251223091120.2413435-1-tangyazhou@zju.edu.cn>
syzbot ci has tested the following series
[v2] bpf: Add value tracking for BPF_DIV
https://lore.kernel.org/all/20251223091120.2413435-1-tangyazhou@zju.edu.cn
* [PATCH bpf-next v2 1/2] bpf: Add interval and tnum analysis for signed and unsigned BPF_DIV
* [PATCH bpf-next v2 2/2] selftests/bpf: Add tests for BPF_DIV analysis
and found the following issue:
WARNING in reg_bounds_sanity_check
Full report is available here:
https://ci.syzbot.org/series/9bfb8ed3-0d6e-4ae4-93a1-e5d466326f9e
***
WARNING in reg_bounds_sanity_check
tree: bpf-next
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next.git
base: ec439c38013550420aecc15988ae6acb670838c1
arch: amd64
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
config: https://ci.syzbot.org/builds/67e90945-0cc5-47d7-a492-406b63cd4281/config
C repro: https://ci.syzbot.org/findings/5808370d-6cee-4ff9-9a6f-ba4007533b78/c_repro
syz repro: https://ci.syzbot.org/findings/5808370d-6cee-4ff9-9a6f-ba4007533b78/syz_repro
------------[ cut here ]------------
verifier bug: REG INVARIANTS VIOLATION (alu): range bounds violation u64=[0x1, 0x0] s64=[0x1, 0x0] u32=[0x1, 0x0] s32=[0x1, 0x0] var_off=(0x1, 0x0)
WARNING: kernel/bpf/verifier.c:2748 at reg_bounds_sanity_check+0x201/0xc30 kernel/bpf/verifier.c:2742, CPU#0: syz.0.17/5999
Modules linked in:
CPU: 0 UID: 0 PID: 5999 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:reg_bounds_sanity_check+0x3e6/0xc30 kernel/bpf/verifier.c:2742
Code: 98 00 00 00 4c 8b 8c 24 88 00 00 00 41 ff 34 24 41 57 55 41 55 ff b4 24 f0 00 00 00 ff b4 24 a8 00 00 00 ff b4 24 c0 00 00 00 <67> 48 0f b9 3a 48 83 c4 38 49 bf 00 00 00 00 00 fc ff df 48 8b 84
RSP: 0018:ffffc90004277098 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 1ffff11022c96804 RCX: 0000000000000001
RDX: ffffffff8b71cd00 RSI: ffffffff8b71bae0 RDI: ffffffff8f861280
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 000000000000000c R11: 0000000000000000 R12: ffff8881164b4020
R13: 0000000000000001 R14: 1ffff11022c96803 R15: 0000000000000001
FS: 000055555eb0e500(0000) GS:ffff88818e835000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fad443e7dac CR3: 00000001bc680000 CR4: 00000000000006f0
Call Trace:
<TASK>
check_alu_op kernel/bpf/verifier.c:16205 [inline]
do_check_insn kernel/bpf/verifier.c:20533 [inline]
do_check+0xa72c/0xeba0 kernel/bpf/verifier.c:20802
do_check_common+0x19cc/0x25b0 kernel/bpf/verifier.c:24080
do_check_main kernel/bpf/verifier.c:24163 [inline]
bpf_check+0x5e7a/0x1c300 kernel/bpf/verifier.c:25470
bpf_prog_load+0x13ba/0x1a10 kernel/bpf/syscall.c:3088
__sys_bpf+0x5c3/0x8a0 kernel/bpf/syscall.c:6207
__do_sys_bpf kernel/bpf/syscall.c:6320 [inline]
__se_sys_bpf kernel/bpf/syscall.c:6318 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6318
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fad4418f7c9
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:00007ffe64db1fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fad443e5fa0 RCX: 00007fad4418f7c9
RDX: 0000000000000094 RSI: 0000200000000340 RDI: 0000000000000005
RBP: 00007fad441f297f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fad443e5fa0 R14: 00007fad443e5fa0 R15: 0000000000000003
</TASK>
----------------
Code disassembly (best guess):
0: 98 cwtl
1: 00 00 add %al,(%rax)
3: 00 4c 8b 8c add %cl,-0x74(%rbx,%rcx,4)
7: 24 88 and $0x88,%al
9: 00 00 add %al,(%rax)
b: 00 41 ff add %al,-0x1(%rcx)
e: 34 24 xor $0x24,%al
10: 41 57 push %r15
12: 55 push %rbp
13: 41 55 push %r13
15: ff b4 24 f0 00 00 00 push 0xf0(%rsp)
1c: ff b4 24 a8 00 00 00 push 0xa8(%rsp)
23: ff b4 24 c0 00 00 00 push 0xc0(%rsp)
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: 48 83 c4 38 add $0x38,%rsp
33: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15
3a: fc ff df
3d: 48 rex.W
3e: 8b .byte 0x8b
3f: 84 .byte 0x84
***
If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
Tested-by: syzbot@syzkaller.appspotmail.com
---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.
parent reply other threads:[~2025-12-23 13:50 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20251223091120.2413435-1-tangyazhou@zju.edu.cn>]
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