Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753897AbXJWQYa (ORCPT ); Tue, 23 Oct 2007 12:24:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752025AbXJWQYX (ORCPT ); Tue, 23 Oct 2007 12:24:23 -0400 Received: from smtp28.orange.fr ([80.12.242.99]:59151 "EHLO smtp28.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751992AbXJWQYW (ORCPT ); Tue, 23 Oct 2007 12:24:22 -0400 X-ME-UUID: 20071023161747531.81D577000097@mwinf2821.orange.fr Date: Tue, 23 Oct 2007 18:13:21 +0200 From: Philippe Elie To: Linus Torvalds , Linux Kernel Mailing List , Andrew Morton , Sami Farin Subject: Re: [patch 1/2] oProfile: oops when profile_pc() return ~0LU Message-ID: <20071023161321.GA2884@zaniah> References: <20071021120842.GA2886@zaniah> <20071023101007.3y62tufa6yxrqk4w@m.safari.iki.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071023101007.3y62tufa6yxrqk4w@m.safari.iki.fi> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3766 Lines: 100 On Tue, 23 Oct 2007 at 13:10 +0000, Sami Farin wrote: > On Mon, Oct 22, 2007 at 19:38:10 -0700, Linus Torvalds wrote: > > > > This set of two patches look ok by me, but I'd like sign-offs.. Also, were > > they tested and found to fix the problem by Sami? > > > > Linus For the signed-offs I thought the From: was an implicit Signed-offs. Test was done privately, Sami helped to narrow down the trouble, but he didn't test the last patch, nothing bad on Sami side, I was too confident the fix was obvious after narrowing it. > > The previous patch I tested by Philippe, oprof-fix-profile_pc-use.patch, > worked ok, but with this latest patch oprofiled aborts. > But kernel does not oops or print msgs. argh, I just moved the wrong eip from kernel to user space where the same problem occur too, *sighs*, since I can't reproduce Sami problem, my own test obviously worked... Sami, can you test this new patch. After testing can you report the contents of /dev/oprofile/stats/cpu*/sample_invalid_eip ? Linus, there is two way to fix this problem, the attached patch fix it by sanitizing the sampled eip, the other is to replace the use of profile_pc(); by instruction_pointer(); in cpu_buffer.c, that one was tested by Sami but 1) it'll break the 'use oprofile as a sort of lockometer' 2) I think sanitizing the eip will be necessary anyway as I'm not really confident than instruction_pointer() can never return weird eip on some weird arch and/or some weird circumstances. diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c index a83c3db..c93d3d2 100644 --- a/drivers/oprofile/cpu_buffer.c +++ b/drivers/oprofile/cpu_buffer.c @@ -64,6 +64,8 @@ int alloc_cpu_buffers(void) b->head_pos = 0; b->sample_received = 0; b->sample_lost_overflow = 0; + b->backtrace_aborted = 0; + b->sample_invalid_eip = 0; b->cpu = i; INIT_DELAYED_WORK(&b->work, wq_sync_buffer); } @@ -175,6 +177,11 @@ static int log_sample(struct oprofile_cpu_buffer * cpu_buf, unsigned long pc, cpu_buf->sample_received++; + if (pc == ESCAPE_CODE) { + cpu_buf->sample_invalid_eip++; + return 0; + } + if (nr_available_slots(cpu_buf) < 3) { cpu_buf->sample_lost_overflow++; return 0; diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h index 49900d9..c66c025 100644 --- a/drivers/oprofile/cpu_buffer.h +++ b/drivers/oprofile/cpu_buffer.h @@ -42,6 +42,7 @@ struct oprofile_cpu_buffer { unsigned long sample_received; unsigned long sample_lost_overflow; unsigned long backtrace_aborted; + unsigned long sample_invalid_eip; int cpu; struct delayed_work work; } ____cacheline_aligned; diff --git a/drivers/oprofile/oprofile_stats.c b/drivers/oprofile/oprofile_stats.c index f0acb66..d1f6d77 100644 --- a/drivers/oprofile/oprofile_stats.c +++ b/drivers/oprofile/oprofile_stats.c @@ -26,6 +26,8 @@ void oprofile_reset_stats(void) cpu_buf = &cpu_buffer[i]; cpu_buf->sample_received = 0; cpu_buf->sample_lost_overflow = 0; + cpu_buf->backtrace_aborted = 0; + cpu_buf->sample_invalid_eip = 0; } atomic_set(&oprofile_stats.sample_lost_no_mm, 0); @@ -61,6 +63,8 @@ void oprofile_create_stats_files(struct super_block * sb, struct dentry * root) &cpu_buf->sample_lost_overflow); oprofilefs_create_ro_ulong(sb, cpudir, "backtrace_aborted", &cpu_buf->backtrace_aborted); + oprofilefs_create_ro_ulong(sb, cpudir, "sample_invalid_eip", + &cpu_buf->sample_invalid_eip); } oprofilefs_create_ro_atomic(sb, dir, "sample_lost_no_mm", - 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/