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 Received: from picard.linux.it (picard.linux.it [213.254.12.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A6EB1C6FD1D for ; Tue, 14 Mar 2023 13:17:48 +0000 (UTC) Received: from picard.linux.it (localhost [IPv6:::1]) by picard.linux.it (Postfix) with ESMTP id C67793CD4F0 for ; Tue, 14 Mar 2023 14:17:46 +0100 (CET) Received: from in-5.smtp.seeweb.it (in-5.smtp.seeweb.it [217.194.8.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by picard.linux.it (Postfix) with ESMTPS id 82AA83CAD42 for ; Tue, 14 Mar 2023 14:17:37 +0100 (CET) Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by in-5.smtp.seeweb.it (Postfix) with ESMTPS id E22C0600879 for ; Tue, 14 Mar 2023 14:17:36 +0100 (CET) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 06FD721A8B; Tue, 14 Mar 2023 13:17:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1678799856; 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=MYNo7WyrIG78xorFu7SYMdFfeLUaDvOsLp75QFcwHCc=; b=SE2IeozDkJkJRjoiSLQtBVsD84lW2WI/D2R/ruDttWbfmpEETtcw7vqu45dreT7zP0EYI+ hLZLhTw7tVFDRlasGqw2waLxffiwkf+yCdwaHTtJ9zEFxkelhYKAyd0hKP4ycANrX4y6nl ho5FiNC4NjqLSM1lLk+ObdLumShubp4= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1678799856; 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=MYNo7WyrIG78xorFu7SYMdFfeLUaDvOsLp75QFcwHCc=; b=SjDXEr/uJFkqMvo0Nn7AdHnfRt0fxTcKf3vj1j82e6ihRqGQ+AIB3ELYORsKlJJhlvTUiR VJZ0DxNyiLNskJCg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id E01E913A1B; Tue, 14 Mar 2023 13:17:35 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id VqKWNe9zEGTpcgAAMHmgww (envelope-from ); Tue, 14 Mar 2023 13:17:35 +0000 Date: Tue, 14 Mar 2023 14:18:55 +0100 From: Cyril Hrubis To: Richard Palethorpe Message-ID: References: <20230314114037.25581-1-rpalethorpe@suse.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230314114037.25581-1-rpalethorpe@suse.com> X-Virus-Scanned: clamav-milter 0.102.4 at in-5.smtp.seeweb.it X-Virus-Status: Clean Subject: Re: [LTP] [PATCH] Add goals of patch review and tips X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ltp@lists.linux.it Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" Hi! > I see two options for patch review. Either we have a single senior > maintainer who does most of or it is distributed. > > For now I think it needs to be distributed which is beyond the scope > of this commit. > > In order to distribute it we need new contributors to review each > others' work at least for the first few revisions. > > I think that anyone can review a patch if they put the work in to test > it and try to break it. Then understand why it is broken. > > This commit states some ideas about how to do that, plus some tips for > more advanced patch review. > > Signed-off-by: Richard Palethorpe > Cc: Cyril Hrubis > Cc: Andrea Cervesato > Cc: Avinesh Kumar > Cc: Wei Gao > Cc: Petr Vorel > --- > doc/maintainer-patch-review-checklist.txt | 78 ++++++++++++++++++++++- > 1 file changed, 77 insertions(+), 1 deletion(-) > > diff --git a/doc/maintainer-patch-review-checklist.txt b/doc/maintainer-patch-review-checklist.txt > index 706b0a516..be0cd0961 100644 > --- a/doc/maintainer-patch-review-checklist.txt > +++ b/doc/maintainer-patch-review-checklist.txt > @@ -1,4 +1,80 @@ > -# Maintainer Patch Review Checklist > +# Patch Review > + > +Anyone can and should review patches. It's the only way to get good at > +patch review and for the project to scale. > + > +## Goals of patch review > + Maybe start with: 1. Catch typos and obvious mistakes Everyone does these and usually they are easy to spot for anyone but the author. > +1. Prevent false positive test results > +2. Prevent false negative test results > +3. Make future changes as easy as possible I would say that number 3 maybe be a bit controversial, I've seen cases where attempts to futureproof the code caused steep increase in the test complexity. So maybe: 3. Keep the code as simple as possible as well as futureproof Or something along the lines. > +## How to find clear errors > + > +A clear error is one where there is unlikely to be any argument if you > +provide evidence of it. Evidence being an error trace or logical proof > +that an error will occur in a common situation. > + > +The following are examples and may not be appropriate for all tests. > + > +* Merge the patch. It should apply cleanly to master. > +* Compile the patch with default and non-default configurations. > + - Use sanitizers e.g. undefined behaviour, address. > + - Compile on non-x86 > + - Compile on x86 with -m32 Maybe note here that some tests trigger undefined behavior intentionally, we do have a few tests that dereference NULL to trigger crash, etc. > +* Use `make check` > +* Run effected tests in a VM > + - Use single vCPU > + - Use many vCPUs and enable NUMA > + - Restrict RAM to < 1GB. > +* Run effected tests on an embedded device > +* Run effected tests on non-x86 machine in general > +* Run reproducers on a kernel where the bug is present > +* Run tests with "-i0" > +* Compare usage of system calls with man page descriptions > +* Compare usage of system calls with kernel code > +* Search the LTP library for existing helper functions > + > +## How to find subtle errors > + > +A subtle error is one where you can expect some argument because you > +do not have clear evidence of an error. It is best to state these as > +questions and not make assertions if possible. > + > +Although if it is a matter of style or "taste" then senior maintainers > +can assert what is correct to avoid bike shedding. > + > +* Ask what happens if there is an error, could it be debugged just > + with the test output? > +* Are we testing undefined behaviour? > + - Could future kernel behaviour change without "breaking userland"? > + - Does the kernel behave differently depending on hardware? > + - Does it behave differently depending kernel on configuration? > + - Does it behave differently depending on the compiler? > +* Will it scale to tiny and huge systems? > + - What happens if there are 100+ CPUs? > + - What happens if each CPU core is very slow? > + - What happens if there are 2TB or RAM? > +* Are we repeating a pattern that can be turned into a library function? > +* Is a single test trying to do too much? > +* Could multiple similar tests be merged? > +* Race conditions > + - What happens if a process gets preempted? > + - Could checkpoints or fuzzsync by used instead? > + - Note, usually you can insert a sleep to prove a race condition > + exists however finding them is hard > +* Is there a simpler way to achieve the same kernel coverage? > + > +## How to get patches merged > + > +Once you think a patch is good enough you should add your Reviewed-by > +tags. This means you will get some credit for getting the patch > +merged. Also some blame if there are problems. Maybe we should mention the Tested-by: tag explicitly here as well. > +In addition you can expect others to review your patches and add their > +tags. This will speed up the process of getting your patches merged. > + > +## Maintainers Checklist > > Patchset should be tested locally and ideally also in maintainer's fork in > GitHub Actions on GitHub. > -- > 2.39.2 > -- Cyril Hrubis chrubis@suse.cz -- Mailing list info: https://lists.linux.it/listinfo/ltp