Hi Zi, On <Date of Zi's email>, Zi Yan wrote: > On 9 Jul 2025, at 8:32, wang lian wrote: > >> Hi Zi Yan, >> Thanks for testing the patch and reporting this build failure. >> I don't have an arm64 environment readily available for testing, so I >> appreciate you catching this. I suspect this is caused by missing or >> older userspace headers in the cross-compilation toolchain. > > Right. My /usr/include/sys does not have pidfd.h. IMHO selftests > should not rely on userspace headers, otherwise we cannot test > latest kernel changes. > >> I will try to fix this in the next version. If the problem persists, a >> good solution would be to manually define the syscall wrapper to avoid >> the dependency on <sys/pidfd.h>. > > Based on what I see in other mm tests, the following patch fixes my > compilation issue. > > [ ... patch snippet ... ]
Thank you very much for not only identifying the root cause but also providing a concrete patch to fix the compilation issue. Your analysis that selftests should be independent of userspace headers is spot on, and this approach aligns perfectly with the feedback I've received. I have integrated your suggested changes into my local tree and will include them in the next version of the patch. I will also be sure to add your "Suggested-by" tag in the commit message to properly credit your contribution. Your help has been invaluable. Best regards, Wang Lian
