Re: [REGRESSION][PATCH] mqueue: Ignore the validity of abs_timeoutparameter when message can be performed immediately

From: Andrew Morton
Date: Wed Mar 14 2012 - 17:46:06 EST


On Fri, 02 Mar 2012 16:42:35 +0900
Akira Takeuchi <takeuchi.akr@xxxxxxxxxxxxxxxx> wrote:

> This patch fixes up the regression problem of mq_timed{send,receive} syscall.
>
> When a message of mqueue can be performed immediately,
> the validity of abs_timeout parameter should not be checked.
>
> According to the manpage of mq_timedreceive:
> Under no circumstance shall the operation fail with a timeout
> if a message can be removed from the message queue immediately.
> The validity of the abstime parameter need not be checked
> if a message can be removed from the message queue immediately.
>
> On 2.6.35+ kernel, mq_timed{send,receive} returns EINVAL incorrectly,
> in this situation.
>
> I found this problem during the OPTS testcase
> "conformance/interfaces/mq_timedreceive/10-2":
>
> # ./10-2.test
> FAIL: the validity of abs_timeout is checked
> Test FAILED

Are you able to identify the commit which caused this regression? I'm
guessing

commit 9ca7d8e6834c40a99622bbe4a88aaf64313ae43c
Author: Carsten Emde <C.Emde@xxxxxxxxx>
AuthorDate: Fri Apr 2 22:40:20 2010 +0200
Commit: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue Apr 6 21:50:03 2010 +0200

mqueue: Convert message queue timeout to use hrtimers


> Signed-off-by: Akira Takeuchi <takeuchi.akr@xxxxxxxxxxxxxxxx>
> Signed-off-by: Kiyoshi Owada <owada.kiyoshi@xxxxxxxxxxxxxxxx>
> ---
> ipc/mqueue.c | 31 +++++++++++++++++++++++++++----
> 1 files changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/ipc/mqueue.c b/ipc/mqueue.c
> index 86ee272..7cd4411 100644
> --- a/ipc/mqueue.c
> +++ b/ipc/mqueue.c
> @@ -861,14 +861,22 @@ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
> struct msg_msg *msg_ptr;
> struct mqueue_inode_info *info;
> ktime_t expires, *timeout = NULL;
> + int timeout_param_error = 0;
> struct timespec ts;
> int ret;
>
> if (u_abs_timeout) {
> int res = prepare_timeout(u_abs_timeout, &expires, &ts);
> if (res)
> - return res;
> - timeout = &expires;
> + /*
> + * The validity of the abs_timeout parameter need not be
> + * checked when there is sufficient room in the queue.
> + * So, do not return here, even if the parameter is
> + * invalid.
> + */
> + timeout_param_error = res;
> + else
> + timeout = &expires;
> }
>
> if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
> @@ -916,6 +924,9 @@ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
> if (filp->f_flags & O_NONBLOCK) {
> spin_unlock(&info->lock);
> ret = -EAGAIN;
> + } else if (unlikely(timeout_param_error)) {
> + spin_unlock(&info->lock);
> + ret = timeout_param_error;
> } else {
> wait.task = current;
> wait.msg = (void *) msg_ptr;
> @@ -955,13 +966,21 @@ SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
> struct mqueue_inode_info *info;
> struct ext_wait_queue wait;
> ktime_t expires, *timeout = NULL;
> + int timeout_param_error = 0;
> struct timespec ts;
>
> if (u_abs_timeout) {
> int res = prepare_timeout(u_abs_timeout, &expires, &ts);
> if (res)
> - return res;
> - timeout = &expires;
> + /*
> + * The validity of the abs_timeout parameter need not be
> + * checked if a message can be removed from the message
> + * queue immediately. So, do not return here, even if
> + * the parameter is invalid.
> + */
> + timeout_param_error = res;
> + else
> + timeout = &expires;
> }
>
> audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
> @@ -996,6 +1015,10 @@ SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
> if (filp->f_flags & O_NONBLOCK) {
> spin_unlock(&info->lock);
> ret = -EAGAIN;
> + } else if (unlikely(timeout_param_error)) {
> + spin_unlock(&info->lock);
> + ret = timeout_param_error;
> + msg_ptr = NULL; /* just for shutting up warning */
> } else {
> wait.task = current;
> wait.state = STATE_NONE;
> --
> 1.7.4.1
>
>
> --
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