[PATCH] uml: tlb flushing fix
This patch fixes a fairly serious tlb flushing bug that makes aio use under
uml very unreliable -- SEGVs, Oops and panic()s occur as a result of stale
tlb entires being used by uml when aio switches mms due to the fact that
uml does not implement the activate_mm() hook. This patch introduces a
simple but correct approach (read: hammer) for implementing activate_mm()
in uml by doing a force_flush_all() if the new mm is different from old.
With this patch in place, uml is able to succeed at the aio test case that
was randomly faulting for me before.
Cc: Jeff Dike <jdike@addtoit.com>
Cc: <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-um/mmu_context.h b/include/asm-um/mmu_context.h
index 7529c9c..095bb62 100644
--- a/include/asm-um/mmu_context.h
+++ b/include/asm-um/mmu_context.h
@@ -16,8 +16,12 @@
#define deactivate_mm(tsk,mm) do { } while (0)
+extern void force_flush_all(void);
+
static inline void activate_mm(struct mm_struct *old, struct mm_struct *new)
{
+ if (old != new)
+ force_flush_all();
}
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
