Re: [PATCH V2,0/2]mm: madvise: return correct bytes processed with process_madvise

[Andrew Morton]

On Fri, 11 Mar 2022 20:59:04 +0530 Charan Teja Kalla <quic_charante@xxxxxxxxxxx> wrote:

> With the process_madvise(), always choose to return non zero processed
> bytes over an error. This can help the user to know on which VMA, passed
> in the 'struct iovec' vector list, is failed to advise thus can take the
> decission of retrying/skipping on that VMA.

Thanks, this is not good.

We should have added userspace tests for process_madvise() along with
the syscall itself.  But evidently that was omitted.  If someone
decides to contribute such tests, hopefully they will include checks
for these return values.