cred_guard_mutex: do not return -EINTR to user-space

do_execve() and ptrace_attach() return -EINTR if
mutex_lock_interruptible(->cred_guard_mutex) fails.

This is not right, change the code to return ERESTARTNOINTR.

Perhaps we should also change proc_pid_attr_write().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 6 insertions, 6 deletions

diff --git a/fs/compat.c b/fs/compat.c
index cdd51a3a7c53..fbadb947727b 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1486,8 +1486,8 @@ int compat_do_execve(char * filename,
         if (!bprm)
                 goto out_files;
 
-        retval = mutex_lock_interruptible(&current->cred_guard_mutex);
-        if (retval < 0)
+        retval = -ERESTARTNOINTR;
+        if (mutex_lock_interruptible(&current->cred_guard_mutex))
                 goto out_free;
         current->in_execve = 1;
 
diff --git a/fs/exec.c b/fs/exec.c
index e639957d7a57..4a8849e45b21 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1277,8 +1277,8 @@ int do_execve(char * filename,
         if (!bprm)
                 goto out_files;
 
-        retval = mutex_lock_interruptible(&current->cred_guard_mutex);
-        if (retval < 0)
+        retval = -ERESTARTNOINTR;
+        if (mutex_lock_interruptible(&current->cred_guard_mutex))
                 goto out_free;
         current->in_execve = 1;
 
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 61c78b2c07ba..082c320e4dbf 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -181,8 +181,8 @@ int ptrace_attach(struct task_struct *task)
          * interference; SUID, SGID and LSM creds get determined differently
          * under ptrace.
          */
-        retval = mutex_lock_interruptible(&task->cred_guard_mutex);
-        if (retval < 0)
+        retval = -ERESTARTNOINTR;
+        if (mutex_lock_interruptible(&task->cred_guard_mutex))
                 goto out;
 
         task_lock(task);