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| author | Guillaume Autran <gautran@mrv.com> | 2005-07-13 01:10:45 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-07-13 11:25:24 -0700 |
| commit | ddca3b80cef36cc668f924ef5154a79acb19ebd7 (patch) | |
| tree | 2cfb8ac6837682d975a1cb761360977ac54a6aef | |
| parent | 88bd5121d635136e01369141367f315665534b3c (diff) | |
| download | op-kernel-dev-ddca3b80cef36cc668f924ef5154a79acb19ebd7.zip op-kernel-dev-ddca3b80cef36cc668f924ef5154a79acb19ebd7.tar.gz | |
[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 <gautran@mrv.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | include/asm-ppc/mmu_context.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/asm-ppc/mmu_context.h b/include/asm-ppc/mmu_context.h index ccabbce..afe26ff 100644 --- a/include/asm-ppc/mmu_context.h +++ b/include/asm-ppc/mmu_context.h @@ -149,6 +149,7 @@ static inline void get_mmu_context(struct mm_struct *mm) */ 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(struct mm_struct *mm) atomic_inc(&nr_free_contexts); #endif } + preempt_enable(); } static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, |
