On Tue, 26 May 2026 13:38:48 +0200 Chris Gellermann <[email protected]> wrote:
> Subject: [PATCH] selftest: Fix UB of getline due to missing var init hm, what's "UB". Please expand the acronym. > 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. Does the test crash? If not, how come? Luck? > Same issue fixed in mlock-random-test. > > [1] https://man7.org/linux/man-pages/man3/getline.3.html The two affected files are testing significantly different parts of the kernel. > Fixes: 41585bbeeef9 ("selftests: add tests for clone3() with *set_tid") > Fixes: 26b4224d9961 ("selftests: expanding more mlock selftest") And these were separated by three years. So can you please split this into a two-patch series? And I suggest you add "Cc: <[email protected]>" to each one. Please retain David's ack on both. Thanks.
