Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify

[~andy/linux] / kernel / exit.c

diff --git a/kernel/exit.c b/kernel/exit.c
index 21aa7b3001fb49edce43446dd85898f62ab33d98..676149a4ac5ff497367a484e2b66c01e915ccefd 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -914,6 +914,15 @@ NORET_TYPE void do_exit(long code)
        if (unlikely(!tsk->pid))
                panic("Attempted to kill the idle task!");
 
+       /*
+        * If do_exit is called because this processes oopsed, it's possible
+        * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before
+        * continuing. Amongst other possible reasons, this is to prevent
+        * mm_release()->clear_child_tid() from writing to a user-controlled
+        * kernel address.
+        */
+       set_fs(USER_DS);
+
        tracehook_report_exit(&code);
 
        validate_creds_for_do_exit(tsk);