Re: [Xen-devel] [PATCH] x86: hold mm->page_table_lock while doing vmalloc_sync

Jeremy Fitzhardinge
2010-10-15T17:07:26Z

On 10/14/2010 01:56 PM, Jeremy Fitzhardinge wrote:
> Take mm->page_table_lock while syncing the vmalloc region. This prevents
> a race with the Xen pagetable pin/unpin code, which expects that the
> page_table_lock is already held. If this race occurs, then Xen can see
> an inconsistent page type (a page can either be read/write or a pagetable
> page, and pin/unpin converts it between them), which will cause either
> the pin or the set_p[gm]d to fail; either will crash the kernel.

I've merged this into tip/x86/mm, which had some conflicting changes
(and fixed up some whitespace issues in one of those changes):

The following changes since commit a416e9e1dde0fbcf20cda59df284cc0dcf2aadc4:

x86-32: Fix sparse warning for the __PHYSICAL_MASK calculation (2010-10-07 16:36:17 -0700)

are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git x86-mm

Jeremy Fitzhardinge (2):
x86/mm: fix bogus whitespace in sync_global_pgds()
x86: hold mm->page_table_lock while doing vmalloc_sync

arch/x86/include/asm/pgtable.h | 2 +
arch/x86/mm/fault.c | 11 ++++++++-
arch/x86/mm/init_64.c | 51 ++++++++++++++++++++++-----------------
arch/x86/mm/pgtable.c | 20 +++++++++++++--
4 files changed, 58 insertions(+), 26 deletions(-)

J