tree 1a0e73e7d933d1cae4b84ba720332f55d378952c
parent 6f205a4c69037e4d8fdf33088a852b64500df012
author Steven J. Magnani <steve@digidescorp.com> 1297361533 -0600
committer Michal Simek <monstr@monstr.eu> 1299654599 +0100

microblaze: Fix /dev/zero corruption from __clear_user()

A userland read of more than PAGE_SIZE bytes from /dev/zero results in
(a) not all of the bytes returned being zero, and
(b) memory corruption due to zeroing of bytes beyond the user buffer.

This is caused by improper constraints on the assembly __clear_user function.
The constrints don't indicate to the compiler that the pointer argument is
modified. Since the function is inline, this results in double-incrementing
of the pointer when __clear_user() is invoked through a multi-page read() of
/dev/zero.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Acked-by: Michal Simek <monstr@monstr.eu>
CC: stable@kernel.org