netdev - Re: [PATCH net-next 0/4] vsock/test: Tests for memory leaks

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Message-ID: <f3bce5dd-1cfb-4094-b80d-584bd00333d5@rbox.co>
Date: Fri, 13 Dec 2024 01:41:56 +0100
From: Michal Luczaj <mhal@...x.co>
To: Stefano Garzarella <sgarzare@...hat.com>
Cc: netdev@...r.kernel.org
Subject: Re: [PATCH net-next 0/4] vsock/test: Tests for memory leaks

On 12/10/24 17:25, Stefano Garzarella wrote:
>> [...]
>> I initially considered triggering (and parsing) a kmemleak scan after each
>> test, but ultimately concluded that the slowdown and the required
>> privileges would be too much.
> 
> Yeah, what about adding something in the README to suggest using
> kmemleak and how to check that everything is okay after a run?

Something like this?

diff --git a/tools/testing/vsock/README b/tools/testing/vsock/README
index 84ee217ba8ee..0d6e73ecbf4d 100644
--- a/tools/testing/vsock/README
+++ b/tools/testing/vsock/README
@@ -36,6 +36,21 @@ Invoke test binaries in both directions as follows:
                        --control-port=1234 \
                        --peer-cid=3
 
+Some tests are designed to produce kernel memory leaks. Leaks detection,
+however, is deferred to Kernel Memory Leak Detector. It is recommended to enable
+kmemleak (CONFIG_DEBUG_KMEMLEAK=y) and explicitly trigger a scan after each test
+run, e.g.
+
+  # echo clear > /sys/kernel/debug/kmemleak
+  # $TEST_BINARY ...
+  # echo "wait for any grace periods" && sleep 2
+  # echo scan > /sys/kernel/debug/kmemleak
+  # echo "wait for kmemleak" && sleep 5
+  # echo scan > /sys/kernel/debug/kmemleak
+  # cat /sys/kernel/debug/kmemleak
+
+For more information see Documentation/dev-tools/kmemleak.rst.
+
 vsock_perf utility
 -------------------
 'vsock_perf' is a simple tool to measure vsock performance. It works in

> I'd suggest also to add something about that in each patch that
> introduce tests where we expects the user to check kmemleak,
> at least with a comment on top of the test functions, and maybe
> also in the commit description.

Sure, will do.

Thanks,
Michal