From mboxrd@z Thu Jan 1 00:00:00 1970 From: Miles Lane Subject: Re: 2.6.35-rc2-git1 - include/linux/cgroup.h:534 invoked rcu_dereference_check() without protection! Date: Wed, 9 Jun 2010 13:00:20 -0400 Message-ID: References: <20100608001929.GF2387@linux.vnet.ibm.com> <1275986441.5408.111.camel@twins> <1276004075.2987.208.camel@twins> <1276097068.1745.13.camel@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: paulmck@linux.vnet.ibm.com, Vivek Goyal , Eric Paris , Lai Jiangshan , Ingo Molnar , LKML , nauman@google.com, eric.dumazet@gmail.com, netdev@vger.kernel.org, Jens Axboe , Gui Jianfeng , Li Zefan , Johannes Berg To: Peter Zijlstra Return-path: Received: from mail-ww0-f46.google.com ([74.125.82.46]:55411 "EHLO mail-ww0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753347Ab0FIRAW convert rfc822-to-8bit (ORCPT ); Wed, 9 Jun 2010 13:00:22 -0400 Received: by wwb31 with SMTP id 31so435394wwb.19 for ; Wed, 09 Jun 2010 10:00:20 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Jun 9, 2010 at 11:29 AM, Miles Lane wrot= e: > On Wed, Jun 9, 2010 at 11:24 AM, Peter Zijlstra wrote: >> On Wed, 2010-06-09 at 11:11 -0400, Miles Lane wrote: >>> >>> Sorry. =A0I misunderstood this message when I first read it. =A0I d= idn't >>> realize this message include a new version of the patch. >>> Anyhow, I just tried to apply the patch to 2.6.35-rc2-git3 and got = this: >>> >>> # patch -p1 -l -F 20 --dry-run < ../5.patch >>> patching file include/linux/cgroup.h >>> patching file kernel/sched.c >>> Hunk #1 succeeded at 306 with fuzz 1. >>> Hunk #3 FAILED at 4462. >>> Hunk #4 succeeded at 4487 with fuzz 3. >>> 1 out of 4 hunks FAILED -- saving rejects to file kernel/sched.c.re= j >> >> Weird.. it seems to apply without trouble to Linus' git tree. >> >> root@twins:/usr/src/linux-2.6# git checkout -f origin/master >> HEAD is now at 84f7586... Merge branch 'for-linus' of git://git.kern= el.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 >> root@twins:/usr/src/linux-2.6# quilt push >> Applying patch patches/sched-rcu-validation.patch >> patching file include/linux/cgroup.h >> patching file kernel/sched.c >> >> Now at patch patches/sched-rcu-validation.patch >> root@twins:/usr/src/linux-2.6# git describe >> v2.6.35-rc2-54-g84f7586 > > Oh. =A0Duh. I know what is going on. =A0I had received another patch = to > sched.c. =A0They must conflict. =A0I will test with just your patch n= ow. > ACPI: Core revision 20100428 [ 0.061088] [ 0.061090] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D [ 0.062009] [ INFO: suspicious rcu_dereference_check() usage. ] [ 0.062138] --------------------------------------------------- [ 0.062268] kernel/sched.c:616 invoked rcu_dereference_check() without protection! [ 0.062470] [ 0.062471] other info that might help us debug this: [ 0.062472] [ 0.062835] [ 0.062836] rcu_scheduler_active =3D 1, debug_locks =3D 1 [ 0.063009] no locks held by swapper/0. [ 0.063134] [ 0.063135] stack backtrace: [ 0.063378] Pid: 0, comm: swapper Not tainted 2.6.35-rc2-git3 #3 [ 0.063507] Call Trace: [ 0.063638] [] lockdep_rcu_dereference+0x9d/0xa5 [ 0.063773] [] task_group+0x7b/0x8a [ 0.064012] [] set_task_rq+0x15/0x6e [ 0.064143] [] set_task_cpu+0xa9/0xba [ 0.064274] [] sched_fork+0x10a/0x1b3 [ 0.064405] [] copy_process+0x617/0x10e6 [ 0.064537] [] do_fork+0x175/0x39b [ 0.064670] [] ? up+0xf/0x39 [ 0.064800] [] ? up+0xf/0x39 [ 0.065013] [] ? do_raw_spin_lock+0x79/0x13e [ 0.065148] [] kernel_thread+0x70/0x72 [ 0.065279] [] ? kernel_init+0x0/0x1ce [ 0.065411] [] ? kernel_thread_helper+0x0/0x10 [ 0.065545] [] ? rcu_scheduler_starting+0x2a/0x4c [ 0.065679] [] rest_init+0x21/0xde [ 0.065810] [] start_kernel+0x448/0x453 [ 0.066013] [] x86_64_start_reservations+0xb3/0xb= 7 [ 0.066148] [] x86_64_start_kernel+0x14c/0x15b [ 0.066499] Setting APIC routing to flat