On Sat, 24 Aug 2013 13:44:49 +0200 Svenning S__rensen <[email protected]> wrote:
> According to 'man msgrcv': > "If msgtyp is less than 0, the first message of the lowest type that is less > than or equal to the absolute value of msgtyp shall be received." > > Bug: The kernel only returns a message if its type is 1; other messages with > type < abs(msgtype) will never get returned. > > Fix: After having traversed the list to find the first message with the > lowest type, we need to actually return that message. > > Signed-off-by: Svenning Soerensen <[email protected]> > > diff --git a/ipc/msg.c b/ipc/msg.c > index bd60d7e..9f29d9e 100644 > --- a/ipc/msg.c > +++ b/ipc/msg.c > @@ -839,7 +839,7 @@ static inline void free_copy(struct msg_msg *copy) > > static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int > mode) > { > - struct msg_msg *msg; > + struct msg_msg *msg, *found = NULL; > long count = 0; > > list_for_each_entry(msg, &msq->q_messages, m_list) { > @@ -848,6 +848,7 @@ static struct msg_msg *find_msg(struct msg_queue *msq, > long *msgtyp, int mode) > *msgtyp, mode)) { > if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) { > *msgtyp = msg->m_type - 1; > + found = msg; Should we continue the search in this case, or should the code immediately return this message? > } else if (mode == SEARCH_NUMBER) { > if (*msgtyp == count) > return msg; > @@ -857,7 +858,7 @@ static struct msg_msg *find_msg(struct msg_queue *msq, > long *msgtyp, int mode) > } > } > > - return ERR_PTR(-EAGAIN); > + return found ?: ERR_PTR(-EAGAIN); > } > > long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int > msgflg, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
