On Thu, Sep 30, 2021 at 10:39:14AM -0700, Yang Shi wrote:

On Thu, Sep 30, 2021 at 9:49 AM Hugh Dickins [off-list ref] wrote:

quoted

I assume you're thinking of one of the fuzzer blkdev ones:
https://lore.kernel.org/linux-mm/CACkBjsbtF_peC7N_4mRfHML_BeiPe+O9DahTfr84puSG_J9rcQ@mail.gmail.com/ (local)
or
https://lore.kernel.org/lkml/CACkBjsYwLYLRmX8GpsDpMthagWOjWWrNxqY6ZLNQVr6yx+f5vA@mail.gmail.com/ (local)

I haven't started on those ones yet: yes, I imagine one or both of those
will need a further fix (S_ISREG() check somewhere if we're lucky; but
could well be nastier); but for the bug in this thread, I expect

Makes sense to me. We should be able to check S_ISREG() in khugepaged,
if it is not a regular file, just bail out. Sounds not that nasty to
me AFAIU.

I don't see why we should have an S_ISREG() check.  I agree it's not the
intended usecase, but it ought to work fine.  Unless there's something
I'm missing?