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t=1717154598; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=6MKGKYsRXHwrNrAl3lmaoTrrWO0EY8d++5MCut8e92c=; b=Anhu6J0Ns+2+NuIR8OjzqS6TAb1VZ7tSxPSgrPH0f0oy06aG2WJvhpZfSCdlGov9lfRXix Tyc6VMhFiWmQ3KCA== Date: Fri, 31 May 2024 13:23:18 +0200 (CEST) From: Miroslav Benes To: Joe Lawrence cc: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/2] livepatch: Add compiler optimization disclaimer/docs In-Reply-To: <20200721161407.26806-1-joe.lawrence@redhat.com> Message-ID: References: <20200721161407.26806-1-joe.lawrence@redhat.com> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Spam-Flag: NO X-Spam-Score: -4.30 X-Spam-Level: X-Spamd-Result: default: False [-4.30 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.980]; MIME_GOOD(-0.10)[text/plain]; MIME_TRACE(0.00)[0:+]; RCVD_COUNT_ZERO(0.00)[0]; ARC_NA(0.00)[]; MID_RHS_MATCH_FROMTLD(0.00)[]; FROM_HAS_DN(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FROM_EQ_ENVFROM(0.00)[]; TO_DN_SOME(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; RCPT_COUNT_THREE(0.00)[3] Hi, On Tue, 21 Jul 2020, Joe Lawrence wrote: > In light of [PATCH] Revert "kbuild: use -flive-patching when > CONFIG_LIVEPATCH is enabled" [1], we should add some loud disclaimers > and explanation of the impact compiler optimizations have on > livepatching. > > The first commit provides detailed explanations and examples. The list > was taken mostly from Miroslav's LPC talk a few years back. This is a > bit rough, so corrections and additional suggestions welcome. Expanding > upon the source-based patching approach would be helpful, too. > > The second commit adds a small README.rst file in the livepatch samples > directory pointing the reader to the doc introduced in the first commit. > > I didn't touch the livepatch kselftests yet as I'm still unsure about > how to best account for IPA here. We could add the same README.rst > disclaimer here, too, but perhaps we have a chance to do something more. > Possibilities range from checking for renamed functions as part of their > build, or the selftest scripts, or even adding something to the kernel > API. I think we'll have a better idea after reviewing the compiler > considerations doc. thanks to Marcos for resurrecting this. Joe, do you have an updated version by any chance? Some things have changed since July 2020 so it calls for a new review. If there was an improved version, it would be easier. If not, no problem at all. Miroslav