Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754254Ab2FOV2c (ORCPT ); Fri, 15 Jun 2012 17:28:32 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:57394 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751749Ab2FOV2a (ORCPT ); Fri, 15 Jun 2012 17:28:30 -0400 Date: Fri, 15 Jun 2012 14:28:24 -0700 From: Greg Kroah-Hartman To: Anton Vorontsov Cc: Kees Cook , Colin Cross , Tony Luck , Steven Rostedt , Frederic Weisbecker , Ingo Molnar , devel@driverdev.osuosl.org, linaro-kernel@lists.linaro.org, Arnd Bergmann , patches@linaro.org, Marco Stornelli , Stephen Boyd , linux-kernel@vger.kernel.org, arve@android.com, Jesper Juhl , John Stultz , Shuah Khan , Rebecca Schultz Zavin , WANG Cong , Andrew Morton , kernel-team@android.com, Thomas Meyer Subject: Re: [PATCH v2 0/6] Function tracing support for pstore Message-ID: <20120615212824.GA23338@kroah.com> References: <20120615170659.GA4060@lizard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120615170659.GA4060@lizard> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2443 Lines: 53 On Fri, Jun 15, 2012 at 10:07:00AM -0700, Anton Vorontsov wrote: > Hi all, > > In v2: > - Do not introduce a separate 'persistent' tracer, but introduce an > option to the existing 'function' tracer. > > Rationale for this patch set: > > With this support kernel can save functions call chain log into a > persistent ram buffer that can be decoded and dumped after reboot > through pstore filesystem. It can be used to determine what function > was last called before a hang or an unexpected reset (caused by, for > example, a buggy driver that abuses HW). > > Here's a "nano howto", to get the idea: > > # mount -t debugfs debugfs /sys/kernel/debug/ > # cd /sys/kernel/debug/tracing > # echo function > current_tracer > # echo 1 > options/func_pstore > # reboot -f > [...] > # mount -t pstore pstore /mnt/ > # tail /mnt/ftrace-ramoops > 0 ffffffff8101ea64 ffffffff8101bcda native_apic_mem_read <- disconnect_bsp_APIC+0x6a/0xc0 > 0 ffffffff8101ea44 ffffffff8101bcf6 native_apic_mem_write <- disconnect_bsp_APIC+0x86/0xc0 > 0 ffffffff81020084 ffffffff8101a4b5 hpet_disable <- native_machine_shutdown+0x75/0x90 > 0 ffffffff81005f94 ffffffff8101a4bb iommu_shutdown_noop <- native_machine_shutdown+0x7b/0x90 > 0 ffffffff8101a6a1 ffffffff8101a437 native_machine_emergency_restart <- native_machine_restart+0x37/0x40 > 0 ffffffff811f9876 ffffffff8101a73a acpi_reboot <- native_machine_emergency_restart+0xaa/0x1e0 > 0 ffffffff8101a514 ffffffff8101a772 mach_reboot_fixups <- native_machine_emergency_restart+0xe2/0x1e0 > 0 ffffffff811d9c54 ffffffff8101a7a0 __const_udelay <- native_machine_emergency_restart+0x110/0x1e0 > 0 ffffffff811d9c34 ffffffff811d9c80 __delay <- __const_udelay+0x30/0x40 > 0 ffffffff811d9d14 ffffffff811d9c3f delay_tsc <- __delay+0xf/0x20 > > Mostly the code comes from trace_persistent.c driver found in the > Android git tree, written by Colin Cross > (according to sign-off history). I reworked the driver a little bit, > and ported it to pstore subsystem. This looks fine to me, but as it touches pstore and tracing code, I can't apply it without acks from the relevant maintainers/owners. thanks, greg k-h -- 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/