From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754511Ab1KHBbZ (ORCPT ); Mon, 7 Nov 2011 20:31:25 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:54400 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754117Ab1KHBal (ORCPT ); Mon, 7 Nov 2011 20:30:41 -0500 X-Authority-Analysis: v=2.0 cv=NJxXCjGg c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=vhdKIqpQuCYA:10 a=WHM5n-Ytuc8A:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=20KFwNOVAAAA:8 a=VwQbUJbxAAAA:8 a=meVymXHHAAAA:8 a=yj0WTn7CRDrG6XgJDsUA:9 a=iK0aRX6K21KmLf-OVogA:7 a=QEXdDO2ut3YA:10 a=jEp0ucaQiEUA:10 a=jeBq3FmKZ4MA:10 a=09PfNBgrfLDYlbvkziIA:9 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-Id: <20111108013040.157614372@goodmis.org> User-Agent: quilt/0.48-1 Date: Mon, 07 Nov 2011 20:29:48 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton Subject: [PATCH 09/10] ftrace: Fix hash record accounting bug References: <20111108012939.372220547@goodmis.org> Content-Disposition: inline; filename=0009-ftrace-Fix-hash-record-accounting-bug.patch Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="00GvhwF7k39YY" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --00GvhwF7k39YY Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable From: Steven Rostedt If the set_ftrace_filter is cleared by writing just whitespace to it, then the filter hash refcounts will be decremented but not updated. This causes two bugs: 1) No functions will be enabled for tracing when they all should be 2) If the users clears the set_ftrace_filter twice, it will crash ftrace: ------------[ cut here ]------------ WARNING: at /home/rostedt/work/git/linux-trace.git/kernel/trace/ftrace.c:13= 84 __ftrace_hash_rec_update.part.27+0x157/0x1a7() Modules linked in: Pid: 2330, comm: bash Not tainted 3.1.0-test+ #32 Call Trace: [] warn_slowpath_common+0x83/0x9b [] warn_slowpath_null+0x1a/0x1c [] __ftrace_hash_rec_update.part.27+0x157/0x1a7 [] ? ftrace_regex_release+0xa7/0x10f [] ? kfree+0xe5/0x115 [] ftrace_hash_move+0x2e/0x151 [] ftrace_regex_release+0xba/0x10f [] fput+0xfd/0x1c2 [] filp_close+0x6d/0x78 [] sys_dup3+0x197/0x1c1 [] sys_dup2+0x4f/0x54 [] system_call_fastpath+0x16/0x1b ---[ end trace 77a3a7ee73794a02 ]--- Link: http://lkml.kernel.org/r/20111101141420.GA4918@debian Reported-by: Rabin Vincent Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 0fcc6ca..7caa450 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1210,7 +1210,9 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable, if (!src->count) { free_ftrace_hash_rcu(*dst); rcu_assign_pointer(*dst, EMPTY_HASH); - return 0; + /* still need to update the function records */ + ret =3D 0; + goto out; } =20 /* --=20 1.7.7 --00GvhwF7k39YY Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIcBAABAgAGBQJOuIZAAAoJEIy3vGnGbaoAZU0P/ArhGkYHjhqqJOWqKMVsRjYU 0wYRZ1aNDK1nYEFX0XpmgzeGBUip2Etu/HIQVPx66k2c6vSu+mnfhiQLd7bZrrvx pD29ol559wqvPmI71cVjuykQrmZHju2HG86o2l7VcOHECk8udC4h+/msbQu7883J KGdBFVAscbAmvUK+05QkPhtaO16Wy4gn283tunDJGjT0z9AYwfy2e3+icMemfa7y iFwGin06mb7t78B3jbTWlE2hcKnwAHtfMyJrCLegdG3QQReXjgp5nEIIdeFMiCe0 GtxIZ5rL+n9CHZD6cY74L9DIt7Ep5IrvoOe3T+VojWnZV45PW/gkl/nBNKkVuHat InCrnsVeAtXInt1vEXwbgLoL84MRfJktPWtBmQgB7MaPyVENB5QzE73c+oLi6WS4 aWXNpjhrmkYLrFNLH6D+ILc8beUvt86YrYU7zeQ7xiTOn7wTxNHDk++z83hAmJc7 a9c/++pUp/6VlBe27fbLCtZK8Ef/644HN/pDevRh+OFMo7X59bv9HRqh4ckgW4p8 cP6avDkziiVg7JlorB0t5QygJB0SdOg+NOmn6gg6gNn5RkWkrdPn81pQA5NdC+OZ ATqVYjxpj2LR0geDzl/abkLPDyjK4NCJqiedOSng3/I1yjUQoLZEFk239UTS19Fg Huw2WgPqjNL3XxCzfu4A =vFqn -----END PGP SIGNATURE----- --00GvhwF7k39YY--