From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753466Ab1F2AsA (ORCPT ); Tue, 28 Jun 2011 20:48:00 -0400 Received: from mail.candelatech.com ([208.74.158.172]:49675 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753196Ab1F2Arx (ORCPT ); Tue, 28 Jun 2011 20:47:53 -0400 From: greearb@candelatech.com To: penberg@kernel.org, cl@linux.com, linux-kernel@vger.kernel.org Cc: Ben Greear Subject: =?UTF-8?q?=5BPATCH=20v2=200/2=5D=20=20SLUB=20memory=20debugging=20improvements=2E?= Date: Tue, 28 Jun 2011 17:47:40 -0700 Message-Id: <1309308462-20124-1-git-send-email-greearb@candelatech.com> X-Mailer: git-send-email 1.7.3.4 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ben Greear The idea is to grab a useful sized stack trace for creation/deletion points instead of just a single method. A second patch adds a command to check if memory should be in use. This logic could be placed in a location that is suspected of accessing freed data. Example output from debugging some funky nfs/rpc behaviour: ============================================================================= BUG kmalloc-64: Object is on free-list ----------------------------------------------------------------------------- INFO: Allocated in rpcb_getport_async+0x39c/0x5a5 [sunrpc] age=381 cpu=3 pid=3750 __slab_alloc+0x348/0x3ba kmem_cache_alloc_trace+0x67/0xe7 rpcb_getport_async+0x39c/0x5a5 [sunrpc] call_bind+0x70/0x75 [sunrpc] __rpc_execute+0x78/0x24b [sunrpc] rpc_execute+0x3d/0x42 [sunrpc] rpc_run_task+0x79/0x81 [sunrpc] rpc_call_sync+0x3f/0x60 [sunrpc] rpc_ping+0x42/0x58 [sunrpc] rpc_create+0x4aa/0x527 [sunrpc] nfs_create_rpc_client+0xb1/0xf6 [nfs] nfs_init_client+0x3b/0x7d [nfs] nfs_get_client+0x453/0x5ab [nfs] nfs_create_server+0x10b/0x437 [nfs] nfs_fs_mount+0x4ca/0x708 [nfs] mount_fs+0x6b/0x152 INFO: Freed in rpcb_map_release+0x3f/0x44 [sunrpc] age=30 cpu=2 pid=29049 __slab_free+0x57/0x150 kfree+0x107/0x13a rpcb_map_release+0x3f/0x44 [sunrpc] rpc_release_calldata+0x12/0x14 [sunrpc] rpc_free_task+0x59/0x61 [sunrpc] rpc_final_put_task+0x82/0x8a [sunrpc] __rpc_execute+0x23c/0x24b [sunrpc] rpc_async_schedule+0x10/0x12 [sunrpc] process_one_work+0x230/0x41d worker_thread+0x133/0x217 kthread+0x7d/0x85 kernel_thread_helper+0x4/0x10 INFO: Slab 0xffffea00029aa470 objects=20 used=9 fp=0xffff8800be7830d8 flags=0x20000000004081 INFO: Object 0xffff8800be7830d8 @offset=4312 fp=0xffff8800be7827a8 Bytes b4 0xffff8800be7830c8: 87 a8 96 00 01 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a .�......ZZZZZZZZ Object 0xffff8800be7830d8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object 0xffff8800be7830e8: 6b 6b 6b 6b 01 08 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkk..kkkkkkkkkk Object 0xffff8800be7830f8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object 0xffff8800be783108: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk� Redzone 0xffff8800be783118: bb bb bb bb bb bb bb bb ������������� Padding 0xffff8800be783258: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ Pid: 29049, comm: kworker/2:2 Not tainted 3.0.0-rc4+ #8 Call Trace: [] print_trailer+0x131/0x13a [] object_err+0x35/0x3e [] verify_mem_not_deleted+0x7a/0xb7 [] rpcb_getport_done+0x23/0x126 [sunrpc] [] rpc_exit_task+0x3f/0x6d [sunrpc] [] __rpc_execute+0x78/0x24b [sunrpc] [] ? rpc_execute+0x42/0x42 [sunrpc] [] rpc_async_schedule+0x10/0x12 [sunrpc] [] process_one_work+0x230/0x41d [] ? process_one_work+0x17b/0x41d [] worker_thread+0x133/0x217 [] ? manage_workers+0x191/0x191 [] kthread+0x7d/0x85 [] kernel_thread_helper+0x4/0x10 [] ? retint_restore_args+0x13/0x13 [] ? __init_kthread_worker+0x56/0x56 [] ? gs_change+0x13/0x13 Ben Greear (2): slub: Enable backtrace for create/delete points. slub: Add method to verify memory is not freed. include/linux/slab.h | 13 ++++++++ mm/slub.c | 80 +++++++++++++++++++++++++++++++++++++++++++++---- 2 files changed, 86 insertions(+), 7 deletions(-) -- 1.7.3.4