From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vineet Gupta Subject: Re: kprobes broken in linux-next (was Re: [tip:perf/kprobes] kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist) Date: Wed, 7 May 2014 10:26:38 +0530 Message-ID: <5369BD06.5020503@synopsys.com> References: <20140417081705.26341.96719.stgit@ltc230.yrl.intra.hitachi.co.jp> <5361DB14.7010406@synopsys.com> <5362F147.6030901@hitachi.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from smtprelay2.synopsys.com ([198.182.60.111]:35507 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750818AbaEGE46 (ORCPT ); Wed, 7 May 2014 00:56:58 -0400 In-Reply-To: <5362F147.6030901@hitachi.com> Sender: linux-next-owner@vger.kernel.org List-ID: To: Masami Hiramatsu , mingo@kernel.org, akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, "linux-arch@vger.kernel.org" , anton Kolesov , linux-next On Friday 02 May 2014 06:43 AM, Masami Hiramatsu wrote: > (2014/05/01 14:26), Vineet Gupta wrote: >> On Thursday 24 April 2014 04:28 PM, tip-bot for Masami Hiramatsu wrote: >>> Commit-ID: 376e242429bf8539ef39a080ac113c8799840b13 >>> Gitweb: http://git.kernel.org/tip/376e242429bf8539ef39a080ac113c8799840b13 >>> Author: Masami Hiramatsu >>> AuthorDate: Thu, 17 Apr 2014 17:17:05 +0900 >>> Committer: Ingo Molnar >>> CommitDate: Thu, 24 Apr 2014 10:02:56 +0200 >>> >>> kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist >>> >>> Introduce NOKPROBE_SYMBOL() macro which builds a kprobes >>> blacklist at kernel build time. >>> >> .... >> >>> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h >>> index 146e4ff..40ceb3c 100644 >>> --- a/include/asm-generic/vmlinux.lds.h >>> +++ b/include/asm-generic/vmlinux.lds.h >>> @@ -109,6 +109,14 @@ >>> #define BRANCH_PROFILE() >>> #endif >>> >>> +#ifdef CONFIG_KPROBES >>> +#define KPROBE_BLACKLIST() VMLINUX_SYMBOL(__start_kprobe_blacklist) = .; \ >>> + *(_kprobe_blacklist) \ >>> + VMLINUX_SYMBOL(__stop_kprobe_blacklist) = .; >>> +#else >>> +#define KPROBE_BLACKLIST() >>> +#endif >>> + >>> #ifdef CONFIG_EVENT_TRACING >>> #define FTRACE_EVENTS() . = ALIGN(8); \ >>> VMLINUX_SYMBOL(__start_ftrace_events) = .; \ >>> @@ -507,6 +515,7 @@ >>> *(.init.rodata) \ >>> FTRACE_EVENTS() \ >>> TRACE_SYSCALLS() \ >>> + KPROBE_BLACKLIST() \ >>> MEM_DISCARD(init.rodata) \ >>> CLK_OF_TABLES() \ >>> RESERVEDMEM_OF_TABLES() \ >> >> Linux-next fails to boot on ARC due to misaligned __start_kprobe_blacklist. Patch >> below fixes it. >> >> ------------------------> >> >From c5afc4ebf9c1c094a260e2aaff6c5b3106063039 Mon Sep 17 00:00:00 2001 >> From: Vineet Gupta >> Date: Thu, 1 May 2014 10:47:29 +0530 >> Subject: [PATCH] kprobes: Ensure blacklist data is aligned >> >> ARC Linux (not supporting native unaligned access) was failing to boot >> because __start_kprobe_blacklist was not aligned. >> >> This was because per generated vmlinux.lds it was emitted right next >> to .rodata with strings etc hence could be randomly unaligned. >> >> Fix that by ensuring a word alignment. While 4 would suffice for 32bit >> arches and problem at hand, it is probably better to put 8. >> >> | Path: (null) CPU: 0 PID: 1 Comm: swapper Not tainted >> | 3.15.0-rc3-next-20140430 #2 >> | task: 8f044000 ti: 8f01e000 task.ti: 8f01e000 >> | >> | [ECR ]: 0x00230400 => Misaligned r/w from 0x800fb0d3 >> | [EFA ]: 0x800fb0d3 >> | [BLINK ]: do_one_initcall+0x86/0x1bc >> | [ERET ]: init_kprobes+0x52/0x120 >> >> Signed-off-by: Vineet Gupta > > Acked-by: Masami Hiramatsu > > Thanks! Hi Ingo/Andrew, Can one of you please pick this up - it doesn't show up in linux-next yet. Thx, -Vineet