Move "exit_robust_list" into mm_release()

We don't want to get rid of the futexes just at exit() time, we want to
drop them when doing an execve() too, since that gets rid of the
previous VM image too.

Doing it at mm_release() time means that we automatically always do it
when we disassociate a VM map from the task.

Reported-by: pageexec@freemail.hu
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Alex Efros <powerman@powerman.name>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/exit.c b/kernel/exit.c
index ae2b92be5faec1efa73beefb63304a22d030fc16..2d8be7ebb0f73499f894a1828fd827f0217290f1 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -40,7 +40,6 @@
 #include <linux/cn_proc.h>
 #include <linux/mutex.h>
 #include <linux/futex.h>
-#include <linux/compat.h>
 #include <linux/pipe_fs_i.h>
 #include <linux/audit.h> /* for audit_free() */
 #include <linux/resource.h>
@@ -1059,14 +1058,6 @@ NORET_TYPE void do_exit(long code)
                exit_itimers(tsk->signal);
        }
        acct_collect(code, group_dead);
-#ifdef CONFIG_FUTEX
-       if (unlikely(tsk->robust_list))
-               exit_robust_list(tsk);
-#ifdef CONFIG_COMPAT
-       if (unlikely(tsk->compat_robust_list))
-               compat_exit_robust_list(tsk);
-#endif
-#endif
        if (group_dead)
                tty_audit_exit();
        if (unlikely(tsk->audit_context))

diff --git a/kernel/fork.c b/kernel/fork.c
index f6083561dfe0a9f8d2a13138f7332bc358a51653..2a372a0e206fa2de99dbfdd594f86f6eb927bf40 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -40,6 +40,7 @@
 #include <linux/jiffies.h>
 #include <linux/tracehook.h>
 #include <linux/futex.h>
+#include <linux/compat.h>
 #include <linux/task_io_accounting_ops.h>
 #include <linux/rcupdate.h>
 #include <linux/ptrace.h>
@@ -519,6 +520,16 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
 {
        struct completion *vfork_done = tsk->vfork_done;
 
+       /* Get rid of any futexes when releasing the mm */
+#ifdef CONFIG_FUTEX
+       if (unlikely(tsk->robust_list))
+               exit_robust_list(tsk);
+#ifdef CONFIG_COMPAT
+       if (unlikely(tsk->compat_robust_list))
+               compat_exit_robust_list(tsk);
+#endif
+#endif
+
        /* Get rid of any cached register state */
        deactivate_mm(tsk, mm);