Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754207AbaJ1PA1 (ORCPT ); Tue, 28 Oct 2014 11:00:27 -0400 Received: from mail-oi0-f48.google.com ([209.85.218.48]:56670 "EHLO mail-oi0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751738AbaJ1PAZ (ORCPT ); Tue, 28 Oct 2014 11:00:25 -0400 MIME-Version: 1.0 In-Reply-To: <544FA8E2.3050404@imgtec.com> References: <544F73CD.1010409@imgtec.com> <544F97D4.4030408@imgtec.com> <544F991E.3070500@imgtec.com> <544FA8E2.3050404@imgtec.com> Date: Wed, 29 Oct 2014 00:00:25 +0900 Message-ID: Subject: Re: Boot problems on Malta with EVA (bisected to 12220dea07f1 "mm/slab: support slab merge") From: Joonsoo Kim To: Markos Chandras Cc: Joonsoo Kim , Christoph Lameter , Pekka Enberg , David Rientjes , Andrew Morton , LKML , linux-mips@linux-mips.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2014-10-28 23:32 GMT+09:00 Markos Chandras : > On 10/28/2014 02:21 PM, Joonsoo Kim wrote: >> 2014-10-28 22:48 GMT+09:00 Joonsoo Kim : >>> 2014-10-28 22:24 GMT+09:00 Markos Chandras : >>>> On 10/28/2014 01:19 PM, Markos Chandras wrote: >>>>> On 10/28/2014 01:01 PM, Joonsoo Kim wrote: >>>>>> 2014-10-28 19:45 GMT+09:00 Markos Chandras : >>>>>>> Hi, >>>>>>> >>>>>>> It seems I am unable to boot my Malta with EVA. The problem appeared in >>>>>>> the 3.18 merge window. I bisected the problem (between v3.17 and >>>>>>> v3.18-rc1) and I found the following commit responsible for the broken boot. >>>>>> >>>>>> Hello, >>>>>> >>>>>> Did you start to bisect from v3.18-rc1? >>>>>> I'd like to be sure that this is another bug which is fixed by following commit. >>>>>> >>>>>> commit 85c9f4b04a08f6bc770b77530c22d04103468b8f >>>>>> Author: Joonsoo Kim >>>>>> Date: Mon Oct 13 15:51:01 2014 -0700 >>>>>> >>>>>> mm/slab: fix unaligned access on sparc64 >>>>>> >>>>>> This fix is merged into v3.18-rc1 sometime later that >>>>>> 'support slab merge' is merged. >>>>>> >>>>>> Thanks. >>>>>> >>>>> Hi, >>>>> >>>>> I bisected from v3.17 until 3.18-rc1. But 3.18-rc2 and the latest >>>>> mainline (f7e87a44ef60ad379e39b45437604141453bf0ec) still have the same >>>>> problem >>>>> >>>>> btw i did more tests and this is not EVA specific. A maltaup_defconfig >>>>> fails in the same way. I suspect all malta*_defconfigs will fail in a >>>>> similar way which makes it probably easier for you to reproduce it on a >>>>> QEMU. >>>>> >>>> >>>> sorry maltaup_defconfig does not fail. maltasmvp_defconfig does. So it >>>> might be a similar problem like the one fixed in >>>> 85c9f4b04a08f6bc770b77530c22d04103468b8f >>> >>> Oops. Sorry. Above commit ('mm/slab: fix unaligned access on sparc64') >>> is irrelevant to this problem. >>> >>> Anyway, your problem would be related to merging with incompatible slab cache. >>> Best way to debug is printing source/target slab cache's object size and >>> alignment and find the problem. I will try to reproduce it using QEMU. >> >> I found that cross compile for MIPS isn't easy job. :) > > You could grab the following toolchain > > https://sourcery.mentor.com/GNUToolchain/release2791 > > (get the IA32 linux tar) > > unpack it somewhere (eg /tmp) and then > > make ARCH=mips maltasmvp_defconfig > make ARCH=mips CROSS_COMPILE=/tmp/mips-2014.05/bin/mips-linux-gnu- -j8 > or something :) Wow!! Really Thanks! I will try it. >> Could you help me to debug the problem with below patch? > > (there are a few build warnings with your patch > mm/slab.c:2065:4: warning: format '%lu' expects argument of type 'long > unsigned int', but argument 5 has type 'size_t' [-Wformat=] > mm/slab.c:2065:4: warning: format '%lu' expects argument of type 'long > unsigned int', but argument 7 has type 'unsigned int' [-Wformat=] > mm/slab.c:2065:4: warning: format '%lu' expects argument of type 'long > unsigned int', but argument 8 has type 'int' [-Wformat=] > mm/slab.c:2065:4: warning: format '%lu' expects argument of type 'long > unsigned int', but argument 9 has type 'int' [-Wformat=] > ) > > but here is the output from a QEMU boot right before the crash > > CPU frequency 200.00 MHz > Calibrating delay loop... 1087.89 BogoMIPS (lpj=5439488) > pid_max: default: 32768 minimum: 301 > __kmem_cache_alias: (cred_jar 92 0) to (kmalloc-128 128 128 128) > __kmem_cache_alias: (files_cache 256 0) to (kmalloc-256 256 128 256) > __kmem_cache_alias: (fs_cache 36 0) to (pid 64 64 44) > __kmem_cache_alias: (names_cache 4096 0) to (kmalloc-4096 4096 128 4096) > __kmem_cache_alias: (mnt_cache 160 0) to (filp 192 64 160) > Mount-cache hash table entries: 4096 (order: 0, 16384 bytes) > Mountpoint-cache hash table entries: 4096 (order: 0, 16384 bytes) > __kmem_cache_alias: (pool_workqueue 256 256) to (kmalloc-256 256 128 256) alignment is mismatch between pool_workqueue and kmalloc-256, but, slab caches are merged, because they have same object size. Perhaps, slab cache for pool_workqueue returns 128 byte aligned memory and workqueue can't work well with it. Quick fix may be something like below, but, I will try it on QEMU MIPS. Thanks. diff --git a/mm/slab_common.c b/mm/slab_common.c index 3a6e0cf..d57b1a2 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -269,6 +269,9 @@ struct kmem_cache *find_mergeable(size_t size, size_t align, if (s->size - size >= sizeof(void *)) continue; + if (align > s->align) + continue; + return s; } return NULL; -- 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/