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From: "Pablo Hugen" <phugen@redhat.com>
To: "Miroslav Benes" <mbenes@suse.cz>,
	"Joe Lawrence" <joe.lawrence@redhat.com>
Cc: "Pablo Hugen" <phugen@redhat.com>,
	<live-patching@vger.kernel.org>,
	<linux-kselftest@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<jpoimboe@kernel.org>, <jikos@kernel.org>, <pmladek@suse.com>,
	<shuah@kernel.org>
Subject: Re: [PATCH] selftests/livepatch: add test for module function patching
Date: Tue, 31 Mar 2026 17:52:27 -0300	[thread overview]
Message-ID: <DHH9KCN1GVWT.3SC8M0FTLBRPP@redhat.com> (raw)
In-Reply-To: <177442832293.70541.15179138173140080388.b4-reply@b4>

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> We sort of test the same in test-callbacks.sh. Just using different
> means. I think I would not mind having this as well.

Ok. The original idea Joe suggested was to check the function output
of module targets directly. From what I can tell, test-callbacks.sh
covers the callbacks and test-ftrace.sh checks that ftrace
can still trace a function after it's been livepatched, neither
actually checks that a replacement function in a module target runs.
I can be wrong though, still getting familiar with the livepatch tests.

> I was *just* in the middle of replying to the patch when yours came in,
> so I'll just move over here.  I had noticed the same thing re:
> test-callbacks.sh despite originally suggested writing this test to
> Pablo (and forgot about the callbacks test module).  With that, I agree
> that it's a nice basic sanity check that's obvious about what it's
> testing.

Fair point. Altough biased I think it is nice to have this explict sanity check.

> A nit but is 'noinline' keyword needed here? proc_create_single() below
> takes a function pointer so hopefully test_klp_mod_target_show() stays
> even without it?

> No strong preference either way.  I won't fault a livepatch developer
> for being paranoid w/respect to the compiler :D

Yeah I think you're right, not strictly needed, just wanted to be sure.
After some experience rebasing kpatch integration tests I've been bitten
enough times to be paranoid about that :)

But since I will work on a follow-up for the other suggestions, I think
I'll drop it there.

Anyways, thanks for the reviews!
Pablo

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  reply	other threads:[~2026-03-31 20:52 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-20 20:11 [PATCH] selftests/livepatch: add test for module function patching Pablo Hugen
2026-03-24 14:22 ` Miroslav Benes
2026-03-24 14:45   ` Joe Lawrence
2026-03-25  8:45     ` Miroslav Benes
2026-03-31 20:52       ` Pablo Hugen [this message]
2026-03-26 14:34 ` Petr Mladek
2026-03-26 20:41   ` Joe Lawrence
2026-03-27 10:46     ` Miroslav Benes
2026-03-31 21:10       ` Pablo Hugen
2026-03-30 13:43     ` Petr Mladek
2026-03-30 13:48     ` speaker-test-module: " Petr Mladek

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