From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C86E0C2BA2B for ; Thu, 9 Apr 2020 14:18:10 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7AC8B20771 for ; Thu, 9 Apr 2020 14:18:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7AC8B20771 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48yjsq6tTCzDqvw for ; Fri, 10 Apr 2020 00:18:07 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=srs0=bany=5z=goodmis.org=rostedt@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=goodmis.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 48yjnP5lTvzDqP9 for ; Fri, 10 Apr 2020 00:14:17 +1000 (AEST) Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9C2212083E; Thu, 9 Apr 2020 14:14:14 +0000 (UTC) Date: Thu, 9 Apr 2020 10:14:13 -0400 From: Steven Rostedt To: Qian Cai Subject: Re: Linux-next POWER9 NULL pointer NIP since 1st Apr. Message-ID: <20200409101413.35d9c72d@gandalf.local.home> In-Reply-To: References: <15AC5B0E-A221-4B8C-9039-FA96B8EF7C88@lca.pw> <87eeszlb6u.fsf@mpe.ellerman.id.au> <0675B22E-8F32-432C-9378-FDE159DD1729@lca.pw> <20200407093054.3eb23e45@gandalf.local.home> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev , LKML , Nicholas Piggin Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, 9 Apr 2020 06:06:35 -0400 Qian Cai wrote: > >> I=E2=80=99ll go to bisect some more but it is going to take a while. > >>=20 > >> $ git log --oneline 4c205c84e249..8e99cf91b99b > >> 8e99cf91b99b tracing: Do not allocate buffer in trace_find_next_entry(= ) in atomic > >> 2ab2a0924b99 tracing: Add documentation on set_ftrace_notrace_pid and = set_event_notrace_pid > >> ebed9628f5c2 selftests/ftrace: Add test to test new set_event_notrace_= pid file > >> ed8839e072b8 selftests/ftrace: Add test to test new set_ftrace_notrace= _pid file > >> 276836260301 tracing: Create set_event_notrace_pid to not trace tasks = =20 > > =20 > >> b3b1e6ededa4 ftrace: Create set_ftrace_notrace_pid to not trace tasks > >> 717e3f5ebc82 ftrace: Make function trace pid filtering a bit more exac= t =20 > >=20 > > If it is affecting function tracing, it is probably one of the above two > > commits. =20 >=20 > OK, it was narrowed down to one of those messed with mcount here, Thing is, nothing here touches mcount. >=20 > 8e99cf91b99b tracing: Do not allocate buffer in trace_find_next_entry() i= n atomic Touches reading the trace buffer. > 2ab2a0924b99 tracing: Add documentation on set_ftrace_notrace_pid and set= _event_notrace_pid Documentation. > 6a13a0d7b4d1 ftrace/kprobe: Show the maxactive number on kprobe_events kprobe output. > c9b7a4a72ff6 ring-buffer/tracing: Have iterator acknowledge dropped events Reading the buffer. > 06e0a548bad0 tracing: Do not disable tracing when reading the trace file Reading the buffer. > 1039221cc278 ring-buffer: Do not disable recording when there is an itera= tor Reading the buffer. > 07b8b10ec94f ring-buffer: Make resize disable per cpu buffer instead of t= otal buffer Resizing the buffer. > 153368ce1bd0 ring-buffer: Optimize rb_iter_head_event() Reading the buffer. > ff84c50cfb4b ring-buffer: Do not die if rb_iter_peek() fails more than th= rice Reading the buffer. > 785888c544e0 ring-buffer: Have rb_iter_head_event() handle concurrent wri= ter Reading the buffer. > 28e3fc56a471 ring-buffer: Add page_stamp to iterator for synchronization Reading the buffer. > bc1a72afdc4a ring-buffer: Rename ring_buffer_read() to read_buffer_iter_a= dvance() Reading the buffer. > ead6ecfddea5 ring-buffer: Have ring_buffer_empty() not depend on tracing = stopped Reading the buffer. > ff895103a84a tracing: Save off entry when peeking at next entry Reading the buffer. > bf2cbe044da2 tracing: Use address-of operator on section symbols Affects trace_printk() > bbd9d05618a6 gpu/trace: add a gpu total memory usage tracepoint New tracepoint infrastructure (just new trace events for gpu) > 89b74cac7834 tools/bootconfig: Show line and column in parse error Extended command line boot config. > 306b69dce926 bootconfig: Support O=3D option Extended command line boot config > 5412e0b763e0 tracing: Remove unused TRACE_BUFFER bits Removed unused enums. > b396bfdebffc tracing: Have hwlat ts be first instance and record count of= instances Affects only the hard ware latency detector (most likely not even configured in the kernel). So I don't understand how any of the above commits can cause a problem. -- Steve