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 9163630C143; Wed, 29 Jul 2026 00:38:15 +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=1785285496; cv=none; b=iWDlHSvmDntv7b4LkSfrBbS0cBrvlhMx9kvwa3vjyIidjdzrySh275W62p2QyvKjpWIyY5NGA1UN2L4jLEk3K5PSNqYwXvBEaXKbSVd7UIoBOOIdngVjsbOzPTzGBMJQHbHhEl4G55UKete+yC027k4cO4+8PTqIvVtDDD/ueCw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785285496; c=relaxed/simple; bh=ctJt+9aDb3KrKE7Eg5rp9kWi5VzKZEDmg87JtKtlGE0=; h=Date:To:From:Subject:Message-Id; b=mkVYkKXwq4Lgf3G5ZP2dPRvK3h7ZvMPrBDQgrdEY095uiTJdqupkvpthL9ewtUVVDS6Is/hIwR9vcwSg4fogpqQE435BiZtUdjl/+QOblBnyyYuzLtuMHkuivwEkOtlJPJ8bknd5J50uZas1IhMxTynJcWAvW/5IOn9o9b25OsE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=M9TZlVNS; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="M9TZlVNS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 174011F000E9; Wed, 29 Jul 2026 00:38:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1785285495; bh=anzs6oyMsrK4ZfMPbs6zi2X8PdJWZYz4xjkuJ2EUzVw=; h=Date:To:From:Subject; b=M9TZlVNSTeAF7XXMoihS3lUea7bZeJAMk/FuPxeBfH7NQGcq8uwFxfsVblWHXthR1 ZyO56m4sKQTRqUatCXG+PcOFVe2F4ja/M/vU/EzEpJSF4TsRD6wPXf+FS20O5785WD tlk+nXw6CR/tpfD4FHZaIX5aFLyVFq14dYlDoh6Q= Date: Tue, 28 Jul 2026 17:38:14 -0700 To: mm-commits@vger.kernel.org,vbabka@kernel.org,surenb@google.com,stable@vger.kernel.org,shuah@kernel.org,rppt@kernel.org,mhocko@suse.com,ljs@kernel.org,liam@infradead.org,david@kernel.org,brauner@kernel.org,christian.gellermann@codasip.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] selftests-clone3-fix-wild-pointer-access-of-getline-due-to-missing-init.patch removed from -mm tree Message-Id: <20260729003815.174011F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: selftests/clone3: fix wild pointer access of getline due to missing init has been removed from the -mm tree. Its filename was selftests-clone3-fix-wild-pointer-access-of-getline-due-to-missing-init.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Chris Gellermann Subject: selftests/clone3: fix wild pointer access of getline due to missing init Date: Wed, 22 Jul 2026 15:02:45 +0200 Patch series "selftests: Add missing initalization of pointer passed to getline", v2. This patch (of 2): Clone3_set_tid uses getline(&line, ...) 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. According to the Open Group Spec[1], char *line has to be null pointer for this: > ssize_t getline(char **restrict lineptr, ...); > If *lineptr is a null pointer or if the object pointed to by *lineptr > is of insufficient size, an object shall be allocated as if by malloc() > or the object shall be reallocated as if by realloc()[...]. However, char *line is only declared, leading to an undefined value that is potentially non-null. In an example run with Musl v1.2.6, the realloc call[2] of getdelim, which implements getline, triggers a segfault: ./run_kselftest.sh --test clone3:clone3_set_tid [ 1366.165898] kselftest: Running tests in clone3 ... [ 1367.799244] clone3_set_tid[811]: unhandled signal 11 code 0x1 at 0x0000000000000000 in libc.so[68184,3fbf69f000+4c000] [ 1367.802808] CPU: 0 UID: 0 PID: 811 Comm: clone3_set_tid Not tainted .. [ 1367.804188] epc: 0x0000003fbf6b0184 [ 1367.804188] ra : 0x0000003fbf6d4664 [ 1367.804188] sp : 0x0000003fce5f2e40 [ 1367.805314] gp : 0x0000002aaab0dfb8 [ 1367.805314] tp : 0x0000003fbf6f14a8 [ 1367.805314] t0 : 0x0000003fbf63d000 ... Looking at the realloc implementation, Musl mallocs for a null pointer memory. But for a non-null pointer, it assumes it's passed a valid pointer to the heap and tries to access its meta-data. This leads to the segfault we see: void *realloc(void *p, size_t n) { if (!p) return malloc(n); if (size_overflows(n)) return 0; struct meta *g = get_meta(p); ... } Fix this by properly initializing the line pointer to NULL. Link: https://lore.kernel.org/20260722130246.2135563-1-christian.gellermann@codasip.com Link: https://lore.kernel.org/20260722130246.2135563-2-christian.gellermann@codasip.com Link: https://pubs.opengroup.org/onlinepubs/9799919799/functions/getline.html [1] Link: https://git.musl-libc.org/cgit/musl/tree/src/stdio/getdelim.c#n38 [2] Fixes: 41585bbeeef9 ("selftests: add tests for clone3() with *set_tid") Signed-off-by: Chris Gellermann Acked-by: David Hildenbrand (arm) Reviewed-by: Lorenzo Stoakes Cc: Christian Brauner Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton --- tools/testing/selftests/clone3/clone3_set_tid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/tools/testing/selftests/clone3/clone3_set_tid.c~selftests-clone3-fix-wild-pointer-access-of-getline-due-to-missing-init +++ a/tools/testing/selftests/clone3/clone3_set_tid.c @@ -141,7 +141,7 @@ int main(int argc, char *argv[]) { FILE *f; char buf; - char *line; + char *line = NULL; int status; int ret = -1; size_t len = 0; _ Patches currently in -mm which might be from christian.gellermann@codasip.com are