Re: [Devel] [PATCH hci-8.1 v2 1/1] selftests/bpf: run the xsk veth tests in a network namespace of their own

["Eva Kurchatova (Virtuozzo)" <eva.kurchatova@virtuozzo.com>]

On 10/22/26 05:53, no-reply@sashiko.virtuozzo.com wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] selftests/bpf: test_xsk.sh netns skip path exits 1 via test_exit()
> --
>
> commit 8857ec024ef596f27390842fbc1312e800d12531
> Author: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
>
> selftests/bpf: run the xsk veth tests in a network namespace of their own
>
> This patch makes test_xsk.sh create a network namespace and re-run itself
> inside it, so the veth pair is isolated from the host's traffic. Because
> the max_skb_frags sysctl isn't visible outside the initial namespace, it
> also adds a -f option to xskxceiver and test_xsk.sh. The commit message
> says the tests are skipped when network namespaces are unavailable.
>
>> diff --git a/tools/testing/selftests/bpf/test_xsk.sh b/tools/testing/selftests/bpf/test_xsk.sh
>> --- a/tools/testing/selftests/bpf/test_xsk.sh
>> +++ b/tools/testing/selftests/bpf/test_xsk.sh
> [ ... ]
>
>> @@ -162,8 +167,27 @@ if [ ! -z $ETH ]; then
>>   	VETH1=${ETH}
>>   else
>>   	validate_root_exec
>> -	validate_veth_support ${VETH0}
>>   	validate_ip_utility
>> +	# The host configures and talks on any new interface in its namespace
>> +	if [ -z "$XSK_NETNS" ]; then
>> +		XSK_NETNS=xsk${VETH0_POSTFIX}
>> +		if ! ip netns add ${XSK_NETNS}; then
>> +			echo "skip all tests: cannot create a network namespace" >&2
>> +			test_exit $ksft_skip
>> +		fi
> [Severity: Medium]
> The commit message says "Without network namespaces the tests are
> skipped", but can this path actually report a skip?
>
> test_exit() is defined in xsk_prereqs.sh as:
>
>      test_exit()
>      {
>          if [ $1 -ne 0 ]; then
>              test_status $1 $(basename $0)
>          fi
>          exit 1
>      }
>
> It prints "[ SKIPPED ]" but then does an unconditional "exit 1" and
> ignores its argument. When "ip netns add" fails (no netns support, no
> permission, read-only /run/netns, name collision), test_xsk.sh will
> therefore exit with status 1, not $ksft_skip (4). The kselftest runner
> will then count that as a failure.
>
> Before this patch, a host without netns support would still run the tests
> in its current namespace. Now such a host reports a failure.
>
> The test_exit() behaviour wasn't introduced by this patch. It already
> affects the existing veth-missing and ip-missing skip paths. This patch
> adds a new call site that depends on it, though, and that site is more
> likely to be hit.
>
> Should test_exit() be changed to "exit $1", or should this path exit with
> $ksft_skip directly, so the skip is reported as the commit message
> describes?
>
>> +		trap "ip netns del ${XSK_NETNS}" EXIT
> [ ... ]

The changelog says so: test_exit() prints the status it is given and 
exits with 1.


It is not this patch's bug, originates in mainline and will take the fix 
to mainline first. This path will not be executed on vzkernel: It is 
only taken where a network namespace can't be created, which anyway is a 
problem for our CI.

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