linux-kernel - Re: [PATCH] signalfd: fill in ssi_int for posix timers and message queues

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Date:	Sat, 3 Jul 2010 12:09:19 -0700 (PDT)
From:	Davide Libenzi <davidel@...ilserver.org>
To:	Nathan Lynch <ntl@...ox.com>
cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] signalfd: fill in ssi_int for posix timers and message
 queues

On Fri, 2 Jul 2010, Nathan Lynch wrote:

> If signalfd is used to consume a signal generated by a POSIX interval
> timer or POSIX message queue, the ssi_int field does not reflect the
> data (sigevent->sigev_value) supplied to timer_create(2) or
> mq_notify(3).  (The ssi_ptr field, however, is filled in.)
> 
> This behavior differs from signalfd's treatment of sigqueue-generated
> signals -- see the default case in signalfd_copyinfo.  It also gives
> results that differ from the case when a signal is handled
> conventionally via a sigaction-registered handler.
> 
> So, set signalfd_siginfo->ssi_int in the remaining cases (__SI_TIMER,
> __SI_MESGQ) where ssi_ptr is set.
> 
> Signed-off-by: Nathan Lynch <ntl@...ox.com>
> ---
>  fs/signalfd.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/signalfd.c b/fs/signalfd.c
> index f329849..1c5a6ad 100644
> --- a/fs/signalfd.c
> +++ b/fs/signalfd.c
> @@ -88,6 +88,7 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
>  		 err |= __put_user(kinfo->si_tid, &uinfo->ssi_tid);
>  		 err |= __put_user(kinfo->si_overrun, &uinfo->ssi_overrun);
>  		 err |= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
> +		 err |= __put_user(kinfo->si_int, &uinfo->ssi_int);
>  		break;
>  	case __SI_POLL:
>  		err |= __put_user(kinfo->si_band, &uinfo->ssi_band);
> @@ -111,6 +112,7 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
>  		err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
>  		err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
>  		err |= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
> +		err |= __put_user(kinfo->si_int, &uinfo->ssi_int);
>  		break;
>  	default:

I am fine with it, but I now noticed that signalfd_copyinfo() got out of 
sync from copy_siginfo_to_user(), which should match.
Do you mind aligning that too, as part of your patch?
An adding a comment on the lines of the one in copy_siginfo_to_user() to 
signalfd_copyinfo() too?
If you do not want to, let me know and I'll do it.


- Davide


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