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[218.164.53.75]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2c164f6d2bbsm124256335ad.1.2026.06.06.02.19.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 06 Jun 2026 02:19:16 -0700 (PDT) Date: Sat, 6 Jun 2026 17:19:04 +0800 From: Shung-Hsi Yu To: Zhenzhong Wu Cc: stable@vger.kernel.org, Paul Chaignon , bpf@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, haoluo@google.com, jolsa@kernel.org, menglong8.dong@gmail.com, tamird@kernel.org, eddyz87@gmail.com Subject: Re: [RFC PATCH 6.1.y 0/2] bpf: backport scalar not-equal tracking fixes Message-ID: References: <20260601180400.1381736-1-jt26wzz@gmail.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Just want to send out a quick reply after looking at this. On Wed, Jun 03, 2026 at 01:25:15AM +0800, Zhenzhong Wu wrote: > Hi Shung-Hsi, ... > I ran the suggested checks with the same reproducer, where BAD means the > program ran and observed the unexpected error, and GOOD means no error was > observed: > > - latest 6.6.y, v6.6.142 (924b4a879cbb): BAD > - bpf-next at b93c55b4932d: GOOD > - bpf-next with the d028f87517d6 JNE refinement reverted: still GOOD > > So the issue still reproduces on the latest 6.6.y, but d028f87517d6 alone > does not explain why bpf-next passes. I'll do more narrowing and update the > candidate backport set accordingly. ... I think it possibly comes down to commit 4bf79f9be434e ("bpf: Track equal scalars history on per-instruction level") added in v6.12. Without that, the precise mark wasn't propogated (for scalars with the same ID), and that likely made the state comparison (invalidly) go through. Shung-Hsi