Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751781AbWHASoy (ORCPT ); Tue, 1 Aug 2006 14:44:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751782AbWHASoy (ORCPT ); Tue, 1 Aug 2006 14:44:54 -0400 Received: from mx1.redhat.com ([66.187.233.31]:51387 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S1751781AbWHASox (ORCPT ); Tue, 1 Aug 2006 14:44:53 -0400 Date: Tue, 1 Aug 2006 14:44:51 -0400 From: Dave Jones To: Linux Kernel Subject: single bit flip detector. Message-ID: <20060801184451.GP22240@redhat.com> Mail-Followup-To: Dave Jones , Linux Kernel Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1854 Lines: 58 In case where we detect a single bit has been flipped, we spew the usual slab corruption message, which users instantly think is a kernel bug. In a lot of cases, single bit errors are down to bad memory, or other hardware failure. This patch adds an extra line to the slab debug messages in those cases, in the hope that users will try memtest before they report a bug. 000: 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b Single bit error detected. Possibly bad RAM. Run memtest86. Signed-off-by: Dave Jones --- linux-2.6.16.noarch/mm/slab.c~ 2006-03-22 18:29:27.000000000 -0500 +++ linux-2.6.16.noarch/mm/slab.c 2006-03-22 18:30:58.000000000 -0500 @@ -1516,10 +1516,33 @@ static void poison_obj(struct kmem_cache static void dump_line(char *data, int offset, int limit) { int i; + unsigned char total=0, bad_count=0; printk(KERN_ERR "%03x:", offset); - for (i = 0; i < limit; i++) + for (i = 0; i < limit; i++) { + if (data[offset+i] != POISON_FREE) { + total += data[offset+i]; + ++bad_count; + } printk(" %02x", (unsigned char)data[offset + i]); + } printk("\n"); + if (bad_count == 1) { + switch (total) { + case POISON_FREE ^ 0x01: + case POISON_FREE ^ 0x02: + case POISON_FREE ^ 0x04: + case POISON_FREE ^ 0x08: + case POISON_FREE ^ 0x10: + case POISON_FREE ^ 0x20: + case POISON_FREE ^ 0x40: + case POISON_FREE ^ 0x80: + printk (KERN_ERR "Single bit error detected. Possibly bad RAM.\n"); +#ifdef CONFIG_X86 + printk (KERN_ERR "Run memtest86 or other memory test tool.\n"); +#endif + return; + } + } } #endif -- http://www.codemonkey.org.uk - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/