From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 21E8A3F8704; Tue, 26 May 2026 12:19:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779797968; cv=none; b=ED+NBpQu/cf/rzM2T+Fi4gFkPwLm6LFyR9r3jX0tEAkwACH/PEf4PmoCXWbdICloUWjtj3EWkMuzHhblbm7qOBoW+h52yGUUI7TZRh1PfiYSQXEuKxWnayEgWsKiyT6iK39sd1n+ReKsOqR0yOd1+4Dx9WG9BPb3d4PYwpMrZy4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779797968; c=relaxed/simple; bh=+Zf2jmU0pis99XbpvYPW55qfhfJYHGvpN1+9Acw6l+M=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=F4mzq4czUuYFBFO9RlJzgPDAIB3dvSe251WVWfxjLACpng9aI/kLEI9P7ujBC6FLoOkGtNb29QEZI5a40YALwSWg/dyPLabAsW+yPTcdHbusWMCn8hggCnndFdL01aygUIvNoqCtDd62ib9QVJVTXqCx9osdFZs/L2TAVbuYwOo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GSaWGJ9K; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GSaWGJ9K" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17F191F000E9; Tue, 26 May 2026 12:19:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779797966; bh=r3KFgS+dBJ7AtckYVi8TqfdsNz+bkVbcNrWm5ZFn5kw=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=GSaWGJ9KG2F1HkMmfxJ7wOTOGRL4udLwwqcQ4fC1OMgS4Se3tMy6hRMvtvxL0joiD 7WjHHRrHx+RvW5adHDZQNedwBiUgLmB0a+Az4Ps9r+zx6KkyU0raupKfrPzb1d7wqL FMV1Umdvd7jVqnV3vYHcf0oYp9uKzzMpfCYH+V40QT48IkKRvpg9raT1SA8nXqYxul Kt+6Ru+6hIwRULdOFsO0MrKigsttMUlGhT4Yg50D0TIrAE2Zz/6ynceVU+zAG1Ege6 H9+TFYtqaMQiRP65ww/oFAa2Diz4FH+RoxwKOgv+enbn4fqjOgcXthRWTXs3b6iubZ 4QAGt4VuMYd7A== Message-ID: <694e11e5-1022-4ebe-a6f7-121ed4450239@kernel.org> Date: Tue, 26 May 2026 14:19:22 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] selftest: Fix UB of getline due to missing var init To: Chris Gellermann , brauner@kernel.org, shuah@kernel.org, akpm@linux-foundation.org Cc: ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org References: <20260526113848.530105-1-christian.gellermann@codasip.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/26/26 13:38, Chris Gellermann wrote: > Clone3_set_tid uses getline(&line, &len, f) in a loop to read the > child's process status. The code expects that getline allocates the > buffer for the line on the first loop iteration. For this, glibc[1] > requires char *line to be set to NULL: > >> ssize_t getline(char **restrict lineptr, ...) >> If *lineptr is set to NULL before the call, then getline() will >> allocate a buffer for storing the line. > > However, char *line is only declared, leading to an undefined > initialization value. Fix this by properly initializing it to NULL. > > Same issue fixed in mlock-random-test. > > [1] https://man7.org/linux/man-pages/man3/getline.3.html > > Fixes: 41585bbeeef9 ("selftests: add tests for clone3() with *set_tid") > Fixes: 26b4224d9961 ("selftests: expanding more mlock selftest") > Signed-off-by: Chris Gellermann > --- Acked-by: David Hildenbrand (arm) -- Cheers, David