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Mon, 18 May 2026 01:51:33 -0700 (PDT) From: Stepan Ionichev To: andriy.shevchenko@intel.com Cc: geert@linux-m68k.org, andy.shevchenko@gmail.com, andy@kernel.org, hcazarim@yahoo.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Stepan Ionichev Subject: Re: [PATCH] auxdisplay: line-display: fix OOB read on zero-length message_store() Date: Mon, 18 May 2026 13:51:20 +0500 Message-Id: <20260518085120.926-1-sozdayvek@gmail.com> X-Mailer: git-send-email 2.33.0.windows.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Mon, May 18, 2026 at 11:15:00AM +0300, Andy Shevchenko wrote: > Good points. Should I drop the patch and ask for a new commit message > (and Fixes tag)? The current line-display.c message_store() calls linedisp_display(linedisp, buf, count) unconditionally, with no count == 0 short-circuit, so write(fd, "", 0) still reaches msg[-1]. The afcb5a811ff3a fix Geert mentions was on img-ascii-lcd's own message_store before the shared code was extracted; when 7e76aece6f03 pulled linedisp_display into line-display.c, the empty-write guard didn't come with it. So both paths trigger the same dereference: zero-byte sysfs writes and PANEL_BOOT_MESSAGE="" via linedisp_attach(). The underlying bug sits in 7e76aece6f03 either way, so I think the existing Fixes is right and no respin is needed. Happy to send v2 with both commits mentioned in the log if you'd prefer that. Stepan