Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756462AbZDXIBZ (ORCPT ); Fri, 24 Apr 2009 04:01:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752160AbZDXIBM (ORCPT ); Fri, 24 Apr 2009 04:01:12 -0400 Received: from mga02.intel.com ([134.134.136.20]:3771 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752088AbZDXIBK (ORCPT ); Fri, 24 Apr 2009 04:01:10 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.40,240,1239001200"; d="scan'208";a="406442833" Date: Fri, 24 Apr 2009 10:00:55 +0200 From: Markus Metzger To: mingo@elte.hu, a.p.zijlstra@chello.nl, akpm@linux-foundation.org Cc: markus.t.metzger@intel.com, markus.t.metzger@gmail.com, roland@redhat.com, eranian@googlemail.com, oleg@redhat.com, juan.villacis@intel.com, ak@linux.jf.intel.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, hpa@zytor.com Subject: [rfc 2/2] x86, bts: use physically non-contiguous trace buffer Message-ID: <20090424100055.A30408@sedona.ch.intel.com> Mime-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.2.5i Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2323 Lines: 68 Use vmalloc to allocate the branch trace buffer. Peter Zijlstra suggested to use vmalloc rather than kmalloc to allocate the potentially multi-page branch trace buffer. Is there a way to have vmalloc allocate a physically non-contiguous buffer for test purposes? Ideally, the memory area would have big holes in it with sensitive data in between so I would know immediately when this is overwritten. Reported-by: Peter Zijlstra CC: Andrew Morton Signed-off-by: Markus Metzger --- arch/x86/kernel/ptrace.c | 5 3 + 2 - 0 ! 1 file changed, 3 insertions(+), 2 deletions(-) Index: b/arch/x86/kernel/ptrace.c =================================================================== --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -626,7 +627,7 @@ static int alloc_bts_buffer(struct bts_c if (err < 0) return err; - buffer = kzalloc(size, GFP_KERNEL); + buffer = vmalloc(size); if (!buffer) goto out_refund; @@ -646,7 +647,7 @@ static inline void free_bts_buffer(struc if (!context->buffer) return; - kfree(context->buffer); + vfree(context->buffer); context->buffer = NULL; refund_locked_memory(context->mm, context->size); --------------------------------------------------------------------- Intel GmbH Dornacher Strasse 1 85622 Feldkirchen/Muenchen Germany Sitz der Gesellschaft: Feldkirchen bei Muenchen Geschaeftsfuehrer: Douglas Lusk, Peter Gleissner, Hannes Schwaderer Registergericht: Muenchen HRB 47456 Ust.-IdNr. VAT Registration No.: DE129385895 Citibank Frankfurt (BLZ 502 109 00) 600119052 This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies. -- 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/