From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Tim Sander" Subject: Re: [ANNOUNCE] 3.0.1-rt8 - Regression to 3.0-rt7 Date: Thu, 11 Aug 2011 19:08:32 +0200 Message-ID: <201108111908.32729.tim.sander@hbm.com> References: <1312580681.28695.44.camel@twins> <201108111804.11136.tim.sander@hbm.com> <1313080781.8491.6.camel@twins> Mime-Version: 1.0 Content-Type: text/Plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "linux-kernel" , "Thomas Gleixner" , "Paul E. McKenney" , "linux-rt-users" To: "Peter Zijlstra" Return-path: Received: from gateway.hbm.com ([213.157.30.2]:12702 "EHLO hbmntx5.hbm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750933Ab1HKRIw convert rfc822-to-8bit (ORCPT ); Thu, 11 Aug 2011 13:08:52 -0400 Content-class: urn:content-classes:message In-Reply-To: <1313080781.8491.6.camel@twins> Sender: linux-rt-users-owner@vger.kernel.org List-ID: Hi Peter > > Yes it works for CONFIG_PREEMPT_RTB=3Dy and as you say not for > > CONFIG_PREEMPT_LL=3Dy. > >=20 > > +++ b/mm/filemap.c > > @@ -2040,7 +2040,7 @@ size_t iov_iter_copy_from_user_atomic(struct = page > > *page, > >=20 > > char *kaddr; > > size_t copied; > >=20 > > - BUG_ON(!current->pagefault_disabled); > > + BUG_ON(!(in_atomic() || current->pagefault_disabled)); >=20 > Ah, I had hoped that bit would have cured the PREEMPT_LL=3Dy config. As stated in the other mail, it was really PREEMPT_LL=3Dy. I hope my er= ror=20 didn't cause you any extra work. > But let me untangle that posix_cpu_timer stuff first, maybe that's in > the way. Which *is* visible by CONFIG_PREEMPT_LL. I just tested 3.0.1 with rt8 patch + the ones i mailed in this thread in both configurations. I can confirm that CONFIG_PREEMPT_RTB=3Dy doesn't show any bugs and CONFIG_PREEMPT_LL shows the following bug: kernel BUG at kernel/posix-cpu-timers.c:1315! = = =20 Unable to handle kernel NULL pointer dereference at virtual address 000= 00000 = =20 pgd =3D c0004000 = = =20 [00000000] *pgd=3D00000000 = = =20 Internal error: Oops: 817 [#1] PREEMPT = = =20 Modules linked in: af_packet i2c_imx(+) netx netx_reset dspload fpgaloa= d=20 mxc_nand(+) nand nand_ids nand_ecc = =20 CPU: 0 Not tainted (3.0.1-pmx-rt8 #2) = = =20 PC is at __bug+0x24/0x30 = = =20 LR is at walk_stackframe+0x24/0x40 = = =20 pc : [] lr : [] psr: 60000113 = = =20 sp : c782ff40 ip : c782fe28 fp : c782ff4c = = =20 r10: 00000001 r9 : 00000000 r8 : c78b2180 = = =20 r7 : c030463c r6 : c782e000 r5 : 00000000 r4 : c78b2180 = = =20 r3 : 00000000 r2 : 00000001 r1 : c782fe58 r0 : 00000034 = = =20 =46lags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel = = =20 Control: 00c5387d Table: 87b84008 DAC: 00000017 Process posixcputmr/0 (pid: 6, stack limit =3D 0xc782e268) Stack: (0xc782ff40 to 0xc7830000) ff40: c782ff8c c782ff50 c005a5c0 c002cbd8 00000000 c782ff54 c782ff54 00= 000000 ff60: 00000000 c78b2180 00000000 c782e000 c030463c c78b2180 00000000 00= 000001 ff80: c782ffbc c782ff90 c005a88c c005a594 00000000 c7817f28 00000000 c7= 82ffcc ffa0: c005a800 00000000 00000000 00000000 c782fff4 c782ffc0 c00570f0 c0= 05a80c ffc0: c7817f28 00000000 00000000 00000000 c782ffd0 c782ffd0 c7817f28 c0= 057064 ffe0: c0040868 00000013 00000000 c782fff8 c0040868 c0057070 cccdcd6c ff= dec890 Backtrace:=20 [] (__bug+0x0/0x30) from []=20 (__run_posix_cpu_timers+0x38/0x278) [] (__run_posix_cpu_timers+0x0/0x278) from []=20 (posix_cpu_timers_thread+0x8c/0x124) [] (posix_cpu_timers_thread+0x0/0x124) from []=20 (kthread+0x8c/0x94) [] (kthread+0x0/0x94) from [] (do_exit+0x0/0x2d8) r7:00000013 r6:c0040868 r5:c0057064 r4:c7817f28 Code: e59f0010 e1a01003 eb086b03 e3a03000 (e5833000)=20 ---[ end trace 09b9f42079c77f6a ]--- Thats enough for me today. Best regards Tim Hottinger Baldwin Messtechnik GmbH, Im Tiefen See 45, 64293 Darmstadt, = Germany | www.hbm.com=20 Registered as GmbH (German limited liability corporation) in the commer= cial register at the local court of Darmstadt, HRB 1147 =20 Company domiciled in Darmstadt | CEO: Andreas Huellhorst | Chairman of = the board: James Charles Webster Als Gesellschaft mit beschraenkter Haftung eingetragen im Handelsregist= er des Amtsgerichts Darmstadt unter HRB 1147=20 Sitz der Gesellschaft: Darmstadt | Geschaeftsfuehrung: Andreas Huellhor= st | Aufsichtsratsvorsitzender: James Charles Webster The information in this email is confidential. It is intended solely fo= r the addressee. If you are not the intended recipient, please let me k= now and delete this email. Die in dieser E-Mail enthaltene Information ist vertraulich und ledigli= ch f=C3=BCr den Empfaenger bestimmt. Sollten Sie nicht der eigentliche = Empfaenger sein, informieren Sie mich bitte kurz und loeschen diese E-M= ail. -- To unsubscribe from this list: send the line "unsubscribe linux-rt-user= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html