On Tue, May 26, 2026 at 11:34:09AM -0700, Andrew Morton wrote: > 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.
Since this looks fine (I also wondered about the fixes too of course), feel free to add my tag to this too: Reviewed-by: Lorenzo Stoakes <[email protected]> > > Thanks. Cheers, Lorenzo
