1 files changed, 12 insertions, 13 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 052a961e41aa..a3a8ce83940f 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1060,7 +1060,6 @@ EXPORT_SYMBOL(install_exec_creds);
 int check_unsafe_exec(struct linux_binprm *bprm)
 {
         struct task_struct *p = current, *t;
-        unsigned long flags;
         unsigned n_fs;
         int res = 0;
 
@@ -1068,21 +1067,22 @@ int check_unsafe_exec(struct linux_binprm *bprm)
 
         n_fs = 1;
         write_lock(&p->fs->lock);
-        lock_task_sighand(p, &flags);
+        rcu_read_lock();
         for (t = next_thread(p); t != p; t = next_thread(t)) {
                 if (t->fs == p->fs)
                         n_fs++;
         }
+        rcu_read_unlock();
 
         if (p->fs->users > n_fs) {
                 bprm->unsafe |= LSM_UNSAFE_SHARE;
         } else {
-                if (p->fs->in_exec)
-                        res = -EAGAIN;
-                p->fs->in_exec = 1;
+                res = -EAGAIN;
+                if (!p->fs->in_exec) {
+                        p->fs->in_exec = 1;
+                        res = 1;
+                }
         }
-
-        unlock_task_sighand(p, &flags);
         write_unlock(&p->fs->lock);
 
         return res;
@@ -1284,6 +1284,7 @@ int do_execve(char * filename,
         struct linux_binprm *bprm;
         struct file *file;
         struct files_struct *displaced;
+        bool clear_in_exec;
         int retval;
 
         retval = unshare_files(&displaced);
@@ -1306,8 +1307,9 @@ int do_execve(char * filename,
                 goto out_unlock;
 
         retval = check_unsafe_exec(bprm);
-        if (retval)
+        if (retval < 0)
                 goto out_unlock;
+        clear_in_exec = retval;
 
         file = open_exec(filename);
         retval = PTR_ERR(file);
@@ -1355,9 +1357,7 @@ int do_execve(char * filename,
                 goto out;
 
         /* execve succeeded */
-        write_lock(&current->fs->lock);
         current->fs->in_exec = 0;
-        write_unlock(&current->fs->lock);
         current->in_execve = 0;
         mutex_unlock(&current->cred_exec_mutex);
         acct_update_integrals(current);
@@ -1377,9 +1377,8 @@ out_file:
         }
 
 out_unmark:
-        write_lock(&current->fs->lock);
-        current->fs->in_exec = 0;
-        write_unlock(&current->fs->lock);
+        if (clear_in_exec)
+                current->fs->in_exec = 0;
 
 out_unlock:
         current->in_execve = 0;