From owner-freebsd-current Sun Oct 13 23:04:43 1996 Return-Path: owner-current Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id XAA29267 for current-outgoing; Sun, 13 Oct 1996 23:04:43 -0700 (PDT) Received: from irz201.inf.tu-dresden.de (irz201.inf.tu-dresden.de [141.76.1.10]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id XAA29239 for ; Sun, 13 Oct 1996 23:04:30 -0700 (PDT) Received: from sax.sax.de (sax.sax.de [193.175.26.33]) by irz201.inf.tu-dresden.de (8.6.12/8.6.12-s1) with ESMTP id HAA01148 for ; Mon, 14 Oct 1996 07:58:38 +0200 Received: (from uucp@localhost) by sax.sax.de (8.6.12/8.6.12-s1) with UUCP id HAA00653 for freebsd-current@FreeBSD.org; Mon, 14 Oct 1996 07:58:37 +0200 Received: (from j@localhost) by uriah.heep.sax.de (8.7.6/8.6.9) id LAA00320 for freebsd-current@FreeBSD.org; Sun, 13 Oct 1996 11:45:12 +0200 (MET DST) From: J Wunsch Message-Id: <199610130945.LAA00320@uriah.heep.sax.de> Subject: Message buffer oddity To: freebsd-current@FreeBSD.org (FreeBSD-current users) Date: Sun, 13 Oct 1996 11:45:12 +0200 (MET DST) Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E X-Mailer: ELM [version 2.4ME+ PL17 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: owner-current@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk Hi all, after upgrading to -current last night, i've seen the strange behaviour of the kernel message buffer below. The only modification i've made is Index: /sys/sys/msgbuf.h =================================================================== RCS file: /home/cvs/src/sys/sys/msgbuf.h,v retrieving revision 1.6 diff -u -u -r1.6 msgbuf.h --- msgbuf.h 1995/08/07 07:58:23 1.6 +++ msgbuf.h 1996/08/17 20:35:16 @@ -37,7 +37,7 @@ #ifndef _SYS_MSGBUF_H_ #define _SYS_MSGBUF_H_ -#define MSG_BSIZE (4096 - 3 * sizeof(unsigned int)) +#define MSG_BSIZE (2 * 4096 - 3 * sizeof(unsigned int)) struct msgbuf { #define MSG_MAGIC 0x063061 unsigned int msg_magic; i.e., the message buffer is increased to (what i think) two pages. Now, the device probe gave me: (ncr0:3:0): "SONY SMO-C501-09 KG 2.13" type 0 removable SCSI 1 od0(ncr0:3:0): Optical 281MB (576999 512 byte sectors) od0(ncr0:3:0): with approximate 18612 cyls, 1 heads, and 31 sectors/track (ncr0:4:0): "TANDBEHi all, after upgrading to -current last night, i've seen the strange behaviour of the kernel message buffer below. The only modification i've made is Index: /sys/sys/msgbuf.h =================================================================== As you can see, the mail i'm just typing goes to the kernel message buffer! (Right after booting, there has been junk in this area.) Normally, this should have been: Oct 13 03:11:31 uriah /kernel: (ncr0:4:0): "TANDBERG TDC 4222 =07:" type 1 removable SCSI 2 Oct 13 03:11:31 uriah /kernel: st0(ncr0:4:0): Sequential-Access Oct 13 03:11:31 uriah /kernel: st0(ncr0:4:0): asynchronous. Oct 13 03:11:31 uriah /kernel: density code 0x0, 512-byte blocks, write-enabled Oct 13 03:11:31 uriah /kernel: Probing for devices on the ISA bus: Oct 13 03:11:31 uriah /kernel: vt0 at 0x60-0x6f irq 1 on motherboard Oct 13 03:11:31 uriah /kernel: vt0: unkown s3, 80 col, color, 8 scr, mf2-kbd, [R3.20-b24] etc. The syslog has registered everything up to the "TANDBE . Right now, dmesg shows me: od0(ncr0:3:0): Optical 281MB (576999 512 byte sectors) od0(ncr0:3:0): with approximate 18612 cyls, 1 heads, and 31 sectors/track (ncr0:4:0): "TANDBElę\^D So the tail of the message buffer is overwritten again and again, at an odd address (*msgbufp + 6905). Is this due to me extending it beyond 4 KB? (The kernel has been recompiled from scratch, and i used to run previous kernels with this modification without problems.) I gonna reboot now again, and see whether this will happen again. Of course, i have to send the mail before... -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)