path: root/ipc
diff options
authorSvenning Sørensen <sss@secomea.dk>2013-08-28 16:35:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-08-28 19:26:38 -0700
commit368ae537e056acd3f751fa276f48423f06803922 (patch)
treec0e8dec82905b231fc74b732fd0966d62d530b22 /ipc
parentOmnikey Cardman 4000: pull in ioctl.h in user header (diff)
IPC: bugfix for msgrcv with msgtyp < 0
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> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc')
1 files changed, 3 insertions, 2 deletions
diff --git a/ipc/msg.c b/ipc/msg.c
index bd60d7e159e8..9f29d9e89bac 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;
} 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,