Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755040Ab3CLIQg (ORCPT ); Tue, 12 Mar 2013 04:16:36 -0400 Received: from mail-bk0-f53.google.com ([209.85.214.53]:59216 "EHLO mail-bk0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754027Ab3CLIQe (ORCPT ); Tue, 12 Mar 2013 04:16:34 -0400 Date: Tue, 12 Mar 2013 09:16:28 +0100 From: Ingo Molnar To: Masami Hiramatsu Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Timo Juhani Lindfors , Ananth N Mavinakayanahalli , Pavel Emelyanov , Jiri Kosina , Nadia Yvette Chambers , yrl.pp-manager.tt@hitachi.com, "David S. Miller" , Andrew Morton , Linus Torvalds Subject: Re: [PATCH -tip ] [BUGFIX] kprobes: Move hash_64() into .text.kprobe section Message-ID: <20130312081628.GA30665@gmail.com> References: <20130311142233.19885.10567.stgit@mhiramat-M0-7522> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130311142233.19885.10567.stgit@mhiramat-M0-7522> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2538 Lines: 69 * Masami Hiramatsu wrote: > Beacuse hash_64() is called from the get_kprobe() inside > int3 handler, kernel causes int3 recursion and crashes if > kprobes user puts a probe on it. > > Usually hash_64() is inlined into caller function, but in > some cases, it has instances by gcc's interprocedural > constant propagation. > > This patch adds __kprobes tag on the hash_64() and moves > all those instances into .text.kprobe section so that > kprobes can refuse probing on the instances. > > I've ensured that all hash_64 instances moves to the > address between __kprobes_text_start and __kprobes_text_end > with this patch as below. > > ffffffff8138bea0 T __kprobes_text_start > ffffffff8138bec0 t hash_64.constprop.8 > ffffffff8138ef98 t hash_64.constprop.26 > ffffffff8138efae t hash_64 > ffffffff8138f066 t hash_64.constprop.43 > ffffffff8138f649 t hash_64.constprop.25 > ffffffff8139103a t hash_64.constprop.77 > ffffffff81391050 t hash_64.constprop.24 > ffffffff81391066 t hash_64.constprop.40 > ffffffff8139107c t hash_64.constprop.15 > ffffffff81391092 T __kprobes_text_end > > Signed-off-by: Masami Hiramatsu > Reported-by: Timo Juhani Lindfors > Cc: "David S. Miller" > Cc: Nadia Yvette Chambers > Cc: Pavel Emelyanov > Cc: Jiri Kosina > Cc: Ananth N Mavinakayanahalli > --- > include/linux/hash.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/linux/hash.h b/include/linux/hash.h > index 61c97ae..d83f62f 100644 > --- a/include/linux/hash.h > +++ b/include/linux/hash.h > @@ -15,6 +15,7 @@ > */ > > #include > +#include I have no objections to the fix itself, but this inclusion of kprobes.h in hash.h is somewhat sad: kprobes.h is a 'fat' header that includes a lot of header files - while hash.h is a really basic type header included in close to a hundred .c files. I think one solution would be for the __kprobes definition to move to a more basic header file - such as types.h or compiler.h (where the 'notrace' attribute is placed too), to stop this header dependency creep. Thanks, Ingo -- 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/