fs/exec.c: move ->recursion_depth out of critical sections

->recursion_depth is changed only by current, therefore decrementing can
be done without taking any locks.

Link: http://lkml.kernel.org/r/20190417213150.GA26474@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 2e0033348d8e..d88584ebf07f 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1652,11 +1652,13 @@ int search_binary_handler(struct linux_binprm *bprm)
                 if (!try_module_get(fmt->module))
                         continue;
                 read_unlock(&binfmt_lock);
+
                 bprm->recursion_depth++;
                 retval = fmt->load_binary(bprm);
+                bprm->recursion_depth--;
+
                 read_lock(&binfmt_lock);
                 put_binfmt(fmt);
-                bprm->recursion_depth--;
                 if (retval < 0 && !bprm->mm) {
                         /* we got to flush_old_exec() and failed after it */
                         read_unlock(&binfmt_lock);