Re: [RFC PATCH] Fix: x86 unaligned __memcpy to/from virtual memory

Linus Torvalds
2015-06-25T00:38:09Z

On Wed, Jun 24, 2015 at 4:54 PM, Mathieu Desnoyers
<mathieu.desnoyers@efficios.com> wrote:
>
> OK, see below. This time the fault occurred at an unaligned address.
> It fails on the !pte_present(*pte_ref) check.

So every time, %rcx is 0x001fb.

Once, your rdx value (which is remaining bytes after the movsq) was 3,
the other two times it's 0.

What's so magical about that 4056-byte copy (+3 bytes once)? Are you
*sure* that copy is valid?

Linus