From: Chris Gellermann Date: Wed, 22 Jul 2026 13:02:46 +0000 (+0200) Subject: selftests/mm: fix potential wild pointer access of getline due to missing init X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9f1d75a4ce04095afdb63d8e540092ff8151dacf;p=thirdparty%2Flinux.git selftests/mm: fix potential wild pointer access of getline due to missing init This is another occurrence of using getline where the code assumes that getline allocates memory to store the line, but the pointer passed to it is uninitialized and potentially a non-null pointer. This violates the Open Group Spec[1] and caused a segfault in a similar situation in selftest/clone3/clone3_set_tid. Fix it by initializing the line pointer to NULL. The issue has been found by simply grepping through the selftest code after running into the issue in clone3_set_tid. Whether it segfaults in its current state is unknown to me. But it's good to be addressed due to defensive reasons. Link: https://lore.kernel.org/20260722130246.2135563-3-christian.gellermann@codasip.com Link: https://pubs.opengroup.org/onlinepubs/9799919799/functions/getline.html [1] Fixes: 26b4224d9961 ("selftests: expanding more mlock selftest") Signed-off-by: Chris Gellermann Acked-by: David Hildenbrand (arm) Reviewed-by: Lorenzo Stoakes Cc: Christian Brauner Cc: Liam R. Howlett Cc: Michal Hocko Cc: Mike Rapoport Cc: Shuah Khan Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton --- diff --git a/tools/testing/selftests/mm/mlock-random-test.c b/tools/testing/selftests/mm/mlock-random-test.c index 9d349c151360..16294bc7dae6 100644 --- a/tools/testing/selftests/mm/mlock-random-test.c +++ b/tools/testing/selftests/mm/mlock-random-test.c @@ -84,7 +84,7 @@ int get_proc_locked_vm_size(void) int get_proc_page_size(unsigned long addr) { FILE *smaps; - char *line; + char *line = NULL; unsigned long mmupage_size = 0; size_t size;