From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751159AbaDOVeE (ORCPT ); Tue, 15 Apr 2014 17:34:04 -0400 Received: from mail-vc0-f176.google.com ([209.85.220.176]:39904 "EHLO mail-vc0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751104AbaDOVdt (ORCPT ); Tue, 15 Apr 2014 17:33:49 -0400 Date: Tue, 15 Apr 2014 17:37:01 -0400 (EDT) From: Vince Weaver To: linux-kernel@vger.kernel.org cc: Thomas Gleixner , Peter Zijlstra , Ingo Molnar Subject: [perf] more perf_fuzzer memory corruption Message-ID: User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Still tracking memory corruption bugs found by the perf_fuzzer, I have about 10 different log splats that I think might all be related to the same underlying problem. Anyway I managed to trigger this using the perf_fuzzer: [ 221.065278] Slab corruption (Not tainted): kmalloc-2048 start=ffff8800cd15e800, len=2048 [ 221.074062] 040: 6b 6b 6b 6b 6b 6b 6b 6b 98 72 57 cd 00 88 ff ff kkkkkkkk.rW..... [ 221.082321] Prev obj: start=ffff8800cd15e000, len=2048 [ 221.087933] 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk [ 221.096224] 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk And luckily I had ftrace running at the time. The allocation of this block is by perf_event perf_fuzzer-2520 [001] 182.980563: kmalloc: (perf_event_alloc+0x55) call_site=ffffffff811399b5 ptr=0xffff8800cd15e800 bytes_req=1272 bytes_alloc=2048 gfp_flags=GFP_KERNEL|GFP_ZERO perf_fuzzer-2520 [000] 183.628515: kmalloc: (perf_event_alloc+0x55) call_site=ffffffff811399b5 ptr=0xffff8800cd15e800 bytes_req=1272 bytes_alloc=2048 gfp_flags=GFP_KERNEL|GFP_ZERO perf_fuzzer-2520 [000] 183.628521: kfree: (perf_event_alloc+0x2f7) call_site=ffffffff81139c57 ptr=0xffff8800cd15e800 perf_fuzzer-2520 [000] 183.628844: kmalloc: (perf_event_alloc+0x55) call_site=ffffffff811399b5 ptr=0xffff8800cd15e800 bytes_req=1272 bytes_alloc=2048 gfp_flags=GFP_KERNEL|GFP_ZERO ...(thousands of times of kmalloc/kfree) Is it worth wading through this mess to try to track down what happened? Vince