linux-kernel - Re: signalfd() not handling sigqueue() sigval data correctly

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Date:	Wed, 9 Apr 2008 12:59:37 -0700 (PDT)
From:	Davide Libenzi <davidel@...ilserver.org>
To:	Michael Kerrisk <mtk.manpages@...glemail.com>
cc:	lkml <linux-kernel@...r.kernel.org>
Subject: Re: signalfd() not handling sigqueue() sigval data correctly

On Tue, 8 Apr 2008, Michael Kerrisk wrote:

> 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




- Davide


---
 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;
 	}
 
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