Re: signalfd() not handling sigqueue() sigval data correctly

From: Michael Kerrisk
Date: Thu Apr 10 2008 - 01:03:45 EST


Hi Davide,

> > I was doing some playing about with signalfd(), and seem to have encountered a
> > bug: when a signalfd read() fetches data for a signal that was sent by
> > sigqueue(), the data accompanying the signal is not returned. Instead
> > ssi_int/ssi_ptr is zero.
>
> Michael, can you give the patch below a spin? I tested it on my x86_64 box
> and seems to be working fine:
>
> Got signal 44
> ssi_code= -1
> ssi_pid = 6314
> ssi_uid = 1000
> ssi_int = 123
> ssi_ptr = 7b

This works for me on x86-32. Thanks Davide!

Cheers,

Michael

> ---
> fs/signalfd.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> Index: linux-2.6.mod/fs/signalfd.c
> ===================================================================
> --- linux-2.6.mod.orig/fs/signalfd.c 2008-04-09 11:53:37.000000000 -0700
> +++ linux-2.6.mod/fs/signalfd.c 2008-04-09 12:05:46.000000000 -0700
> @@ -111,9 +111,14 @@
> err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
> err |= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
> break;
> - default: /* this is just in case for now ... */
> + default:
> + /*
> + * This case catches also the signals queued by sigqueue().
> + */
> 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;
> }
>
>



--
Michael Kerrisk
Maintainer of the Linux man-pages project: http://www.kernel.org/doc/man-pages/
Want to report a man-pages bug? Look here:
http://www.kernel.org/doc/man-pages/reporting_bugs.html
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