tree 2cfb8ac6837682d975a1cb761360977ac54a6aef
parent 88bd5121d635136e01369141367f315665534b3c
author Guillaume Autran <[EMAIL PROTECTED]> Wed, 13 Jul 2005 15:10:45 -0700
committer Linus Torvalds <[EMAIL PROTECTED]> Thu, 14 Jul 2005 01:25:24 -0700
[PATCH] ppc32: fix destroy_context() race condition
Fix for a race condition when a task gets preempted by another task while
executing the destroy_context(...) in a FEW_CONTEXTS environment.
mm->context == NO_CONTEXT but the context_map may indicate all contexts are
in use.
The solution to this problem is to disable kernel preemption while
destroying a MMU context.
Signed-off-by: Guillaume Autran <[EMAIL PROTECTED]>
Acked-by: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
include/asm-ppc/mmu_context.h | 2 ++
1 files changed, 2 insertions(+)
diff --git a/include/asm-ppc/mmu_context.h b/include/asm-ppc/mmu_context.h
--- a/include/asm-ppc/mmu_context.h
+++ b/include/asm-ppc/mmu_context.h
@@ -149,6 +149,7 @@ static inline void get_mmu_context(struc
*/
static inline void destroy_context(struct mm_struct *mm)
{
+ preempt_disable();
if (mm->context != NO_CONTEXT) {
clear_bit(mm->context, context_map);
mm->context = NO_CONTEXT;
@@ -156,6 +157,7 @@ static inline void destroy_context(struc
atomic_inc(&nr_free_contexts);
#endif
}
+ preempt_enable();
}
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
-
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