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From: Yonghong Song <yonghong.song@linux.dev>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Kernel Team <kernel-team@fb.com>,
	Martin KaFai Lau <martin.lau@kernel.org>
Subject: Re: [PATCH bpf-next v2 1/2] bpf: Warn with new bpf_unreachable() kfunc maybe due to uninitialized var
Date: Sat, 17 May 2025 11:13:42 -0700	[thread overview]
Message-ID: <b32cd638-5ba1-4af5-80e6-3103786a7c8e@linux.dev> (raw)
In-Reply-To: <CAADnVQJurPs_e3Lx9O7qZ+=HPk7XarXoGXeTiARbw8bW+-txGA@mail.gmail.com>



On 5/16/25 5:31 AM, Alexei Starovoitov wrote:
> On Fri, May 16, 2025 at 2:17 PM Yonghong Song <yonghong.song@linux.dev> wrote:
>>
>> So I then decided to add an 'exit' insn after bpf_unreachable() in llvm.
>> See latest https://github.com/llvm/llvm-project/pull/131731 (commit #2).
>> So we won't have any control flow issues in code. With newer llvm change,
> That's a good idea. Certainly better than special case this 'noreturn'
> semantic in the verifier.

Current latest llvm21 will cause kernel build failure:
   https://patchew.org/linux/20250506-default-const-init-clang-v2-1-fcfb69703264@kernel.org/
I will wait for the fix in bpf-next and then submit v3.


  reply	other threads:[~2025-05-17 18:14 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-15 20:06 [PATCH bpf-next v2 1/2] bpf: Warn with new bpf_unreachable() kfunc maybe due to uninitialized var Yonghong Song
2025-05-15 20:06 ` [PATCH bpf-next v2 2/2] selftests/bpf: Add a test with bpf_unreachable() kfunc Yonghong Song
2025-05-17  8:45   ` kernel test robot
2025-05-15 22:42 ` [PATCH bpf-next v2 1/2] bpf: Warn with new bpf_unreachable() kfunc maybe due to uninitialized var Alexei Starovoitov
2025-05-16 21:17   ` Yonghong Song
2025-05-16 21:31     ` Alexei Starovoitov
2025-05-17 18:13       ` Yonghong Song [this message]
2025-05-18 15:41         ` Alexei Starovoitov
2025-05-19  0:09           ` Yonghong Song

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