The groups-related functions declared in include/linux/cred.h are defined in kernel/groups.c, which is compiled only when CONFIG_MULTIUSER=y. Move all these function declarations under #ifdef CONFIG_MULTIUSER to help avoid accidental usage in contexts where CONFIG_MULTIUSER might be disabled. This patch also adds a fallback for groups_search(). Currently this function is only called from kernel/groups.c itself and security/keys/permissions.c, where the call is (by coincidence) optimized away in case CONFIG_MULTIUSER=n. However, the audit subsystem (which does not depend on CONFIG_MULTIUSER) calls this function in -next, so the fallback will be needed to avoid compilation errors or ugly workarounds. See also: https://lkml.org/lkml/2018/6/20/670 https://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit.git/commit/... Reported-by: Randy Dunlap <rdunlap(a)infradead.org&gt; Tested-by: Randy Dunlap <rdunlap(a)infradead.org&gt; Signed-off-by: Ondrej Mosnacek <omosnace(a)redhat.com&gt; --- Changes: v2->v3: commit message corrections v1->v2: change default return value of groups_search() to 1 include/linux/cred.h | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/include/linux/cred.h b/include/linux/cred.h index 631286535d0f..7eed6101c791 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -65,6 +65,12 @@ extern void groups_free(struct group_info *); extern int in_group_p(kgid_t); extern int in_egroup_p(kgid_t); +extern int groups_search(const struct group_info *, kgid_t); + +extern int set_current_groups(struct group_info *); +extern void set_groups(struct cred *, struct group_info *); +extern bool may_setgroups(void); +extern void groups_sort(struct group_info *); #else static inline void groups_free(struct group_info *group_info) { @@ -78,12 +84,11 @@ static inline int in_egroup_p(kgid_t grp) { return 1; } +static inline int groups_search(const struct group_info *group_info, kgid_t grp) +{ + return 1; +} #endif -extern int set_current_groups(struct group_info *); -extern void set_groups(struct cred *, struct group_info *); -extern int groups_search(const struct group_info *, kgid_t); -extern bool may_setgroups(void); -extern void groups_sort(struct group_info *); /* * The security context of a task -- 2.17.1