From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 8178 invoked by alias); 28 Jul 2017 15:45:52 -0000 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org Received: (qmail 7873 invoked by uid 48); 28 Jul 2017 15:45:28 -0000 From: "dsmith at redhat dot com" To: systemtap@sourceware.org Subject: [Bug runtime/21859] on rawhide, the context.exp test case causes a kernel warning Date: Fri, 28 Jul 2017 15:45:00 -0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: systemtap X-Bugzilla-Component: runtime X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: dsmith at redhat dot com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: systemtap at sourceware dot org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2017-q3/txt/msg00067.txt.bz2 https://sourceware.org/bugzilla/show_bug.cgi?id=3D21859 --- Comment #1 from David Smith --- The following kernel commit changed module_kallsyms_on_each_symbol(), which= is called by kallsyms_on_each_symbol, to quit doing RCU-style module list traversal and require the module_mutex: =3D=3D=3D=3D commit 0be964be0d45084245673c971d72a4b51690231d Author: Peter Zijlstra Date: Wed May 27 11:09:35 2015 +0930 module: Sanitize RCU usage and locking Currently the RCU usage in module is an inconsistent mess of RCU and RCU-sched, this is broken for CONFIG_PREEMPT where synchronize_rcu() does not imply synchronize_sched(). Most usage sites use preempt_{dis,en}able() which is RCU-sched, but (most of) the modification sites use synchronize_rcu(). With the exception of the module bug list, which actually uses RCU. Convert everything over to RCU-sched. Furthermore add lockdep asserts to all sites, because it's not at all clear to me the required locking is observed, esp. on exported functions. =3D=3D=3D=3D It looks like this patch was first included in kernel version 4.2. So, we'll have to hold the module_mutex when calling kallsyms_on_each_symbol(). --=20 You are receiving this mail because: You are the assignee for the bug.