linux/arch/frv/mm
Peter Zijlstra 20273941f2 mm: fix race in kunmap_atomic()
Christoph reported a nice splat which illustrated a race in the new stack
based kmap_atomic implementation.

The problem is that we pop our stack slot before we're completely done
resetting its state -- in particular clearing the PTE (sometimes that's
CONFIG_DEBUG_HIGHMEM).  If an interrupt happens before we actually clear
the PTE used for the last slot, that interrupt can reuse the slot in a
dirty state, which triggers a BUG in kmap_atomic().

Fix this by introducing kmap_atomic_idx() which reports the current slot
index without actually releasing it and use that to find the PTE and delay
the _pop() until after we're completely done.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reported-by: Christoph Hellwig <hch@infradead.org>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:05 -07:00
..
Makefile frv: unbreak misalignment handling changes 2008-05-01 08:03:58 -07:00
cache-page.c mm: stack based kmap_atomic() 2010-10-26 16:52:08 -07:00
dma-alloc.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
elf-fdpic.c FRV: Miscellaneous fixes 2007-05-08 20:41:14 -07:00
extable.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
fault.c frv: invoke oom-killer from page fault 2010-06-04 15:21:44 -07:00
highmem.c mm: fix race in kunmap_atomic() 2010-10-27 18:03:05 -07:00
init.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
kmap.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
mmu-context.c frv: use find_task_by_vpid in cxn_pin_by_pid 2008-02-05 09:44:20 -08:00
pgalloc.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
tlb-flush.S Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
tlb-miss.S Rename special text sections in arch/frv from .text.XXX to .text..XXX. 2010-03-03 11:26:01 +01:00