From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754576Ab3FFWTP (ORCPT ); Thu, 6 Jun 2013 18:19:15 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:33754 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752146Ab3FFWTL (ORCPT ); Thu, 6 Jun 2013 18:19:11 -0400 X-Authority-Analysis: v=2.0 cv=fZsvOjsF c=1 sm=0 a=rXTBtCOcEpjy1lPqhTCpEQ==:17 a=mNMOxpOpBa8A:10 a=Ciwy3NGCPMMA:10 a=Aa0lt3D-HgIA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=XNm7IlzWS18A:10 a=VwQbUJbxAAAA:8 a=sSGdn24nJPWUM8SqEsUA:9 a=QEXdDO2ut3YA:10 a=rXTBtCOcEpjy1lPqhTCpEQ==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 74.67.115.198 Message-Id: <20130606221654.698742573@goodmis.org> User-Agent: quilt/0.60-1 Date: Thu, 06 Jun 2013 18:16:54 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Linus Torvalds , Ingo Molnar , Andrew Morton , "Paul E. McKenney" Subject: [PATCH 0/4] [GIT PULL] tracing: Fixes with dealing with RCU and context tracking Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="===============4923929107880628099==" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --===============4923929107880628099== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Linus, This includes the same patches as my last pull request with trace-fixes-v3.10-rc3-v2. I added two more fixes to this series. This contains 4 fixes. The first two fix the case where full RCU debugging is enabled, enabling function tracing causes a live lock of the system. This is due to the added debug checks in rcu_dereference_raw() that is used by the function tracer. These checks are also traced by the function tracer as well as cause enough overhead to the function tracer to slow down the system enough that the time to finish an interrupt can take longer than when the next interrupt is triggered, causing a live lock from the timer interrupt. Talking this over with Paul McKenney, we came up with a fix that adds a new rcu_dereference_raw_notrace() that does not perform these added check= s, and let the function tracer use that. The third commit fixes a failed compile when branch tracing is enabled, due to the conversion of the trace_test_buffer() selftest that the branch trace wasn't converted for. The forth patch fixes a bug caught by the RCU lockdep code where a rcu_read_lock() is performed when rcu is disabled (either going to or from idle, or user space). This happened on the irqsoff tracer as it calls task_uid(). The fix here was to use current_uid() when possible that doesn't use rcu locking. Which luckily, is always used when irqsoff calls this code. Please pull the latest trace-fixes-v3.10-rc3-v3 tree, which can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git trace-fixes-v3.10-rc3-v3 Tag SHA1: 0e87101aa65ebfe736070474684d1b38fea4d805 Head SHA1: f17a5194859a82afe4164e938b92035b86c55794 Steven Rostedt (2): rcu: Add _notrace variation of rcu_dereference_raw() and hlist_for_ea= ch_entry_rcu() ftrace: Use the rcu _notrace variants for rcu_dereference_raw() and f= riends Steven Rostedt (Red Hat) (2): tracing: Fix bad parameter passed in branch selftest tracing: Use current_uid() for critical time tracing --===============4923929107880628099==-- include/linux/rculist.h | 20 ++++++++++++++++++++ include/linux/rcupdate.h | 9 +++++++++ kernel/trace/ftrace.c | 18 +++++++++--------- kernel/trace/trace.c | 10 +++++++++- kernel/trace/trace_selftest.c | 2 +- 5 files changed, 48 insertions(+), 11 deletions(-) -- Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAABAgAGBQJRsQraAAoJEOdOSU1xswtMol8H/29q4+otWy8lUgW2I8lmMR+r Bu+iy5zR5L05Rrb5IWuEOgDxQRuKCQN95gI9O91Fc1Wqa9DglxC3lzMtHyOJppZH HtWOv7zspkI6cYjwH1hOiHY2ZtRVQqqHsHrq85JoFFQPptlj0GdyLPtWyRxhSuiM v4EEuPsr/FGc/gCkLkMfwBRs3UD/nrutfUIdo8++ajYSolA5VtQOqUZBtswskSKh x/PjhEfYy3BwQwRYYFYkZDs5Q5G87szPIyvdn1kVzQXzLwiUYn+J/7RAiLhGSsA8 Wa4Jk5Ji2uZIiMCBVCEIzE+ZpXoD9U/MabSc7xYDY5vofu6nsxvdLySxU4YbsRU= =6lYd -----END PGP SIGNATURE----- ----