Messages in this thread | | | From | Dmitry Vyukov <> | Date | Tue, 16 May 2017 15:15:16 -0700 | Subject | Re: [PATCH] [iov_iter] use memmove() when copying to/from user page |
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On Tue, May 16, 2017 at 2:33 PM, Al Viro <viro@zeniv.linux.org.uk> wrote: > On Tue, May 16, 2017 at 02:01:51PM -0700, Dmitry Vyukov wrote: > >> > In that case your patch does not suffice. Overlapping move _forwards_ still >> > yields unexpected results, doesn't it? >> >> Why? memmove can move both ways. Do we need to change more memcpy's to >> memmove's? > > Because it's not going to be *one* call of memcpy() or memmove(). It's > one per page.
I missed that.
I assumed that in the case of sendfile from memfd to memfd data will be copied directly. But it goes through a pipe with multiple buffers. Does not look easily fixable.
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