From: Michael Ellerman <mpe@ellerman.id.au>
To: Torsten Duwe <duwe@lst.de>
Cc: Jiri Kosina <jkosina@suse.cz>, Miroslav Benes <mbenes@suse.cz>,
Petr Mladek <pmladek@suse.com>, Jessica Yu <jeyu@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
live-patching@vger.kernel.org
Subject: Re: [PATCH v7 06/10] ppc64 ftrace: disable profiling for some functions
Date: Wed, 10 Feb 2016 12:50:38 +1100 [thread overview]
Message-ID: <1455069038.7576.6.camel@ellerman.id.au> (raw)
In-Reply-To: <20160204162107.65ECE692DF@newverein.lst.de>
On Mon, 2016-01-25 at 16:31 +0100, Torsten Duwe wrote:
> At least POWER7/8 have MMUs that don't completely autoload;
> a normal, recoverable memory fault might pass through these functions.
> If a dynamic tracer function causes such a fault, any of these functions
> being traced with -mprofile-kernel may cause an endless recursion.
I'm not really happy with this one, still :)
At the moment I can trace these without any problems, with either ftrace or
kprobes, but obviously it was causing you some trouble. So I'd like to
understand why you were having issues when regular tracing doesn't.
If it's the case that tracing can work for these functions, but live patching
doesn't (for some reason), then maybe these should be blocked by the live
patching infrastructure rather than at the ftrace/kprobes level.
cheers
next prev parent reply other threads:[~2016-02-10 1:50 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-04 14:29 [PATCH v7 00/10] ftrace with regs + live patching for ppc64 LE (ABI v2) Torsten Duwe
2016-01-25 15:26 ` [PATCH v7 01/10] ppc64 (le): prepare for -mprofile-kernel Torsten Duwe
2016-01-25 15:27 ` [PATCH v7 02/10] ppc64le FTRACE_WITH_REGS implementation Torsten Duwe
2016-01-25 15:29 ` [PATCH v7 03/10] ppc use ftrace_modify_all_code default Torsten Duwe
2016-01-25 15:29 ` [PATCH v7 04/10] ppc64 ftrace_with_regs configuration variables Torsten Duwe
2016-02-05 14:05 ` Petr Mladek
2016-02-05 14:48 ` Steven Rostedt
2016-02-05 16:18 ` Petr Mladek
2016-02-05 16:30 ` Steven Rostedt
2016-02-06 10:32 ` Torsten Duwe
2016-02-08 10:34 ` Petr Mladek
2016-02-08 12:12 ` Torsten Duwe
2016-02-08 15:23 ` Petr Mladek
2016-02-08 15:49 ` Steven Rostedt
2016-02-08 16:32 ` Petr Mladek
2016-02-09 9:02 ` Torsten Duwe
2016-01-25 15:30 ` [PATCH v7 05/10] ppc64 ftrace_with_regs: spare early boot and low level Torsten Duwe
2016-01-25 15:31 ` [PATCH v7 06/10] ppc64 ftrace: disable profiling for some functions Torsten Duwe
2016-02-10 1:50 ` Michael Ellerman [this message]
2016-02-10 18:01 ` Torsten Duwe
2016-01-25 15:31 ` [PATCH v7 07/10] ppc64 ftrace: disable profiling for some files Torsten Duwe
2016-02-10 0:33 ` Michael Ellerman
2016-02-10 17:50 ` Torsten Duwe
2016-01-25 15:33 ` [PATCH v7 08/10] Implement kernel live patching for ppc64le (ABIv2) Torsten Duwe
2016-01-25 15:33 ` [PATCH v7 09/10] Enable LIVEPATCH to be configured on ppc64le and add livepatch.o if it is selected Torsten Duwe
2016-01-28 15:32 ` [PATCH v7 10/10] livepatch: Detect offset for the ftrace location during build Petr Mladek
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