fs: use rlimit helpers

Make sure compiler won't do weird things with limits.  E.g.  fetching them
twice may return 2 different values after writable limits are implemented.

I.e.  either use rlimit helpers added in commit 3e10e716abf3 ("resource:
add helpers for fetching rlimits") or ACCESS_ONCE if not applicable.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 591030735591..6348d79401de 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -195,7 +195,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
                  *    to work from.
                  */
                 rlim = current->signal->rlim;
-                if (size > rlim[RLIMIT_STACK].rlim_cur / 4) {
+                if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) {
                         put_page(page);
                         return NULL;
                 }
@@ -579,7 +579,7 @@ int setup_arg_pages(struct linux_binprm *bprm,
 
 #ifdef CONFIG_STACK_GROWSUP
         /* Limit stack size to 1GB */
-        stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
+        stack_base = rlimit_max(RLIMIT_STACK);
         if (stack_base > (1 << 30))
                 stack_base = 1 << 30;
 
@@ -1535,7 +1535,7 @@ static int format_corename(char *corename, long signr)
                         /* core limit size */
                         case 'c':
                                 rc = snprintf(out_ptr, out_end - out_ptr,
-                                              "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur);
+                                              "%lu", rlimit(RLIMIT_CORE));
                                 if (rc > out_end - out_ptr)
                                         goto out;
                                 out_ptr += rc;
@@ -1800,7 +1800,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
         struct coredump_params cprm = {
                 .signr = signr,
                 .regs = regs,
-                .limit = current->signal->rlim[RLIMIT_CORE].rlim_cur,
+                .limit = rlimit(RLIMIT_CORE),
         };
 
         audit_core_dumps(signr);