]> git.proxmox.com Git - mirror_ubuntu-disco-kernel.git/commit
SUNRPC: Fix memory corruption issue on 32-bit highmem systems
authorTrond Myklebust <Trond.Myklebust@netapp.com>
Wed, 28 Aug 2013 17:35:13 +0000 (13:35 -0400)
committerTrond Myklebust <Trond.Myklebust@netapp.com>
Wed, 28 Aug 2013 19:43:43 +0000 (15:43 -0400)
commit347e2233b7667e336d9f671f1a52dfa3f0416e2c
treeed2ee6d0122e3bd3ce3c24ab66bb64fab6ae9de8
parentfa8218def1b1a16f0a410e2c1c767b4738cc81fa
SUNRPC: Fix memory corruption issue on 32-bit highmem systems

Some architectures, such as ARM-32 do not return the same base address
when you call kmap_atomic() twice on the same page.
This causes problems for the memmove() call in the XDR helper routine
"_shift_data_right_pages()", since it defeats the detection of
overlapping memory ranges, and has been seen to corrupt memory.

The fix is to distinguish between the case where we're doing an
inter-page copy or not. In the former case of we know that the memory
ranges cannot possibly overlap, so we can additionally micro-optimise
by replacing memmove() with memcpy().

Reported-by: Mark Young <MYoung@nvidia.com>
Reported-by: Matt Craighead <mcraighead@nvidia.com>
Cc: Bruce Fields <bfields@fieldses.org>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: Matt Craighead <mcraighead@nvidia.com>
net/sunrpc/xdr.c