diff options
| author | Svenning Sørensen <sss@secomea.dk> | 2013-08-28 16:35:17 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-08-28 19:26:38 -0700 |
| commit | 368ae537e056acd3f751fa276f48423f06803922 (patch) | |
| tree | c0e8dec82905b231fc74b732fd0966d62d530b22 /ipc/msg.c | |
| parent | aaaafb7f953c60d9c9eeb1b10ecdbe6970421b24 (diff) | |
| download | lwn-368ae537e056acd3f751fa276f48423f06803922.tar.gz lwn-368ae537e056acd3f751fa276f48423f06803922.zip | |
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/msg.c')
| -rw-r--r-- | ipc/msg.c | 5 |
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, |