Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753538Ab3JXBiZ (ORCPT ); Wed, 23 Oct 2013 21:38:25 -0400 Received: from ozlabs.org ([203.10.76.45]:53663 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752407Ab3JXBiY (ORCPT ); Wed, 23 Oct 2013 21:38:24 -0400 From: Rusty Russell To: Ming Lei , Andrew Morton , linux-kernel@vger.kernel.org Cc: Ming Lei , Russell King , linux-arm-kernel@lists.infradead.org, Chen Gang Subject: Re: [RFC PATCH] kernel/kallsyms.c: only show legal kernel symbol In-Reply-To: <1382498320-26594-1-git-send-email-tom.leiming@gmail.com> References: <1382498320-26594-1-git-send-email-tom.leiming@gmail.com> User-Agent: Notmuch/0.15.2 (http://notmuchmail.org) Emacs/23.4.1 (i686-pc-linux-gnu) Date: Thu, 24 Oct 2013 11:51:18 +1030 Message-ID: <87eh7bfoq9.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2176 Lines: 65 Ming Lei writes: > Address of non-module kernel symbol should always be located > from CONFIG_PAGE_OFFSET on, so only show these legal kernel > symbols in /proc/kallsyms. > > On ARM, some symbols(see below) may drop in relocatable code, so > perf can't parse kernel symbols any more from /proc/kallsyms, this > patch fixes the problem. > > 00000000 t __vectors_start > 00000020 A cpu_v7_suspend_size > 00001000 t __stubs_start > 00001004 t vector_rst > 00001020 t vector_irq > 000010a0 t vector_dabt > 00001120 t vector_pabt > 000011a0 t vector_und > 00001220 t vector_addrexcptn > 00001224 t vector_fiq > 00001224 T vector_fiq_offset > > The issue can be fixed in scripts/kallsyms.c too, but looks this > approach is easier. This fix looks hacky; if these symbols are not available, don't just remove them from /proc/kallsyms, but don't put them in the kernel at all. That way, they won't interfere with other kallsyms uses (eg. backtrace). Or, better, figure out a smart way of excluding them by knowing why these symbol addresses are wrong. Thanks, Rusty. > Cc: Russell King > Cc: linux-arm-kernel@lists.infradead.org > Cc: Rusty Russell > Cc: Chen Gang > Signed-off-by: Ming Lei > --- > kernel/kallsyms.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c > index 3127ad5..184f271 100644 > --- a/kernel/kallsyms.c > +++ b/kernel/kallsyms.c > @@ -543,7 +543,7 @@ static int s_show(struct seq_file *m, void *p) > tolower(iter->type); > seq_printf(m, "%pK %c %s\t[%s]\n", (void *)iter->value, > type, iter->name, iter->module_name); > - } else > + } else if (iter->value >= CONFIG_PAGE_OFFSET) > seq_printf(m, "%pK %c %s\n", (void *)iter->value, > iter->type, iter->name); > return 0; > -- > 1.7.9.5 -- 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/