tree e7afc9647b9cc80fb95ee9dae7d9532b67efdc01
parent 65984ff9d2179a97e5a11aaef1e86fdb276cfad5
author Richard Weinberger <richard@nod.at> 1376757960 +0200
committer Richard Weinberger <richard@nod.at> 1378543114 +0200

um: Implement probe_kernel_read()

UML needs it's own probe_kernel_read() to handle kernel
mode faults correctly.
The implementation uses mincore() on the host side to detect
whether a page is owned by the UML kernel process.

This fixes also a possible crash when sysrq-t is used.
Starting with 3.10 sysrq-t calls probe_kernel_read() to
read details from the kernel workers. As kernel worker are
completely async pointers may turn NULL while reading them.

Cc: <stian@nixia.no>
Cc: <tj@kernel.org>
Cc: <stable@vger.kernel.org> # 3.10.x
Signed-off-by: Richard Weinberger <richard@nod.at>