wait: using uninitialized member of wait queue

The "flags" member of "struct wait_queue_t" is used in several places in
the kernel code without beeing initialized by init_wait().  "flags" is
used in bitwise operations.

If "flags" not initialized then unexpected behaviour may take place.
Incorrect flags might used later in code.

Added initialization of "wait_queue_t.flags" with zero value into
"init_wait".

Signed-off-by: Evgeny Kuznetsov <EXT-Eugeny.Kuznetsov@nokia.com>
[ The bit we care about does end up being initialized by both
   prepare_to_wait() and add_to_wait_queue(), so this doesn't seem to
   cause actual bugs, but is definitely the right thing to do -Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/wait.h b/include/linux/wait.h
index 0836ccc5712146f87d13e9e35a9480e980708392..3efc9f3f43a0862cad51aa325e08c9f24d129f8e 100644 (file)
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -614,6 +614,7 @@ int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
                (wait)->private = current;                              \
                (wait)->func = autoremove_wake_function;                \
                INIT_LIST_HEAD(&(wait)->task_list);                     \
+               (wait)->flags = 0;                                      \
        } while (0)
 
 /**