[kbuild-all] Re: [selinuxproject-selinux:stable-5.15 1/1] include/linux/rcupdate.h:395:2: warning: passing argument 1 of 'security_locked_down' discards 'const' qualifier from pointer target type

On Thu, Sep 16, 2021 at 2:08 PM kernel test robot <lkp(a)intel.com&gt; wrote: > tree: https://github.com/SELinuxProject/selinux-kernel stable-5.15 > head: c491f0a471580712a4254adece400c3ebb3d8e44 > commit: c491f0a471580712a4254adece400c3ebb3d8e44 [1/1] lockdown,selinux: fix wrong subject in some SELinux lockdown checks > config: um-x86_64_defconfig (attached as .config) > compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 > reproduce (this is a W=1 build): > # https://github.com/SELinuxProject/selinux-kernel/commit/c491f0a471580712a... > git remote add selinuxproject-selinux https://github.com/SELinuxProject/selinux-kernel > git fetch --no-tags selinuxproject-selinux stable-5.15 > git checkout c491f0a471580712a4254adece400c3ebb3d8e44 > # save the attached .config to linux build tree > make W=1 ARCH=um SUBARCH=x86_64 > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp(a)intel.com&gt; > > All warnings (new ones prefixed by >>): > > In file included from include/linux/rbtree.h:24, > from include/linux/mm_types.h:10, > from include/linux/mmzone.h:21, > from include/linux/gfp.h:6, > from include/linux/mm.h:10, > from drivers/char/mem.c:12: > drivers/char/mem.c: In function 'open_port': > >> include/linux/rcupdate.h:395:2: warning: passing argument 1 of 'security_locked_down' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers] > 395 | ({ \ > | ~^~~ > 396 | RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_protected() usage"); \ > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 397 | rcu_check_sparse(p, space); \ > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 398 | ((typeof(*p) __force __kernel *)(p)); \ > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 399 | }) > | ~~ > include/linux/rcupdate.h:587:2: note: in expansion of macro '__rcu_dereference_protected' > 587 | __rcu_dereference_protected((p), (c), __rcu) > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ > include/linux/cred.h:299:2: note: in expansion of macro 'rcu_dereference_protected' > 299 | rcu_dereference_protected(current->cred, 1) > | ^~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/char/mem.c:620:28: note: in expansion of macro 'current_cred' > 620 | rc = security_locked_down(current_cred(), LOCKDOWN_DEV_MEM); > | ^~~~~~~~~~~~ > In file included from include/linux/fs_context.h:14, > from include/linux/fs_parser.h:11, > from include/linux/shmem_fs.h:11, > from drivers/char/mem.c:25: > include/linux/security.h:1347:53: note: expected 'struct cred *' but argument is of type 'const struct cred *' > 1347 | static inline int security_locked_down(struct cred *cred, enum lockdown_reason what) > | ~~~~~~~~~~~~~^~~~ Ah, I forgot to add the const qualifier to the function definition in the CONFIG_SECURITY=n branch... Paul, will you amend the commit or should I send an updated patch?