IPC: bugfix for msgrcv with msgtyp < 0
commit 368ae537e056acd3f751fa276f48423f06803922 upstream.
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.
This regression was introduced by commit daaf74cf0867 ("ipc: refactor
msg list search into separate function")
Signed-off-by: Svenning Soerensen <sss@secomea.dk>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/ipc/msg.c b/ipc/msg.c
index d0c6d96..f8fbe2c 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -795,7 +795,7 @@
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) {
@@ -804,6 +804,7 @@
*msgtyp, mode)) {
if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
*msgtyp = msg->m_type - 1;
+ found = msg;
} else if (mode == SEARCH_NUMBER) {
if (*msgtyp == count)
return msg;
@@ -813,7 +814,7 @@
}
}
- return ERR_PTR(-EAGAIN);
+ return found ?: ERR_PTR(-EAGAIN);
}