Package: libnss-extrausers Version: 0.6-3 The implementation uses three static global pointer variables:
static FILE *groupsfile = NULL; static FILE *shadowfile = NULL; static FILE *usersfile = NULL; Since these are used without locks or atomic operations, this is not thread-safe, even though NSS functions are supposed to be reentrant. This is leading to occasional "double free or corruption" crashes in libvirtd for us, specifically in fclose(groupsfile); in _nss_extrausers_endgrent. As a quick fix, I suggest declaring these variables thread-local: static __thread FILE *groupsfile = NULL; static __thread FILE *shadowfile = NULL; static __thread FILE *usersfile = NULL; It's not necessarily the most elegant solution, but it should make the code fully reentrant.
