Re: [PATCH blktests] check: add kmemleak support to blktests

[Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>]

On Jan 13, 2026 / 15:21, Nilay Shroff wrote:
> Running blktests can also help uncover kernel memory leaks when the
> kernel is built with CONFIG_DEBUG_KMEMLEAK. However, until now the
> blktests framework had no way to automatically detect or report such
> leaks. Users typically had to manually setup kmemleak and trigger
> scans after running tests[1][2].
> 
> This change integrates kmemleak support directly into the blktests
> framework. Before running each test, the framework checks for the
> presence of /sys/kernel/debug/kmemleak to determine whether kmemleak
> is enabled for the running kernel. If available, before running a test,
> any existing kmemleak reports are cleared to avoid false positives
> from previous tests. After the test completes, the framework explicitly
> triggers a kmemleak scan. If memory leaks are detected, they are written
> to a per-test file at, "results/.../.../<test>.kmemleak" and the
> corresponding test is marked as FAIL. Users can then inspect the
> <test>.kmemleak file to analyze the reported leaks.
> 
> With this enhancement, blktests can automatically detect kernel memory
> leaks (if kerel is configured with CONFIG_DEBUG_KMEMLEAK support)  on
> a per-test basis, removing the need for manual kmemleak setup and scans.
> This should make it easier and faster to identify memory leaks
> introduced by individual tests.
> 
> [1] https://lore.kernel.org/all/CAHj4cs8oJFvz=daCvjHM5dYCNQH4UXwSySPPU4v-WHce_kZXZA@mail.gmail.com/
> [2] https://lore.kernel.org/all/CAHj4cs9wv3SdPo+N01Fw2SHBYDs9tj2M_e1-GdQOkRy=DsBB1w@mail.gmail.com/
> 
> Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>

Nilay, thank you very much. This idea is excellent, and the patch looks good
except one nit comment below. I also did trial runs, and confirmed memory leaks
can be detected and reported as test case failures. Great :)

> diff --git a/check b/check
> index 6d77d8e..3a6e837 100755
> --- a/check
> +++ b/check
[...]
> @@ -451,6 +486,18 @@ _call_test() {
>  				print \"    \" \$0
>  			}" "${seqres}.dmesg"
>  			;;
> +		kmemleak)
> +			echo "    kmemleak detected:"
> +                        awk "
> +                        {
> +                                if (NR > 10) {
> +                                        print \"    ...\"
> +                                        print \"    (See '${seqres}.kmemleak' for the entire message)\"
> +                                        exit
> +                                }
> +                                print \"    \" \$0
> +                        }" "${seqres}.kmemleak"
> +                        ;;

Nit: the hunk above uses spaces for indent. Assuming there is no other review
comments on this patch, I will replace the spaces with tabs when I apply it. I
will wait a few more days to see someone makes comments or not. Thanks.