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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-20 19:23:57 +08:00
linux-next/arch/tile/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
..
elf.c arch/tile: Miscellaneous cleanup changes. 2010-07-06 13:41:51 -04:00
extable.c
fault.c arch/tile: parameterize system PLs to support KVM port 2010-10-15 15:38:09 -04:00
highmem.c mm: fix race in kunmap_atomic() 2010-10-27 18:03:05 -07:00
homecache.c arch/tile: add Tilera's <arch/sim.h> header as an open-source header 2010-10-15 15:36:54 -04:00
hugetlbpage.c arch/tile: Miscellaneous cleanup changes. 2010-07-06 13:41:51 -04:00
init.c arch/tile: parameterize system PLs to support KVM port 2010-10-15 15:38:09 -04:00
Makefile
migrate_32.S
migrate.h
mmap.c
pgtable.c arch: tile: mm: pgtable.c: Removed duplicated #include 2010-08-13 08:10:24 -04:00