From ac2aca2817ca10ad30f86d0d3caa41ea8cc4f0f0 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 23 Feb 2012 01:37:19 -0500 Subject: [PATCH] um: uml_dup_mmap() relies on ->mmap_sem being held, but activate_mm() doesn't hold it ... while calling uml_dup_mmap() Signed-off-by: Al Viro --- arch/um/include/asm/mmu_context.h | 11 +++++++++-- arch/um/kernel/skas/mmu.c | 2 +- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/um/include/asm/mmu_context.h b/arch/um/include/asm/mmu_context.h index 591b3d8..aa4a743 100644 --- a/arch/um/include/asm/mmu_context.h +++ b/arch/um/include/asm/mmu_context.h @@ -9,7 +9,7 @@ #include #include -extern void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm); +extern void uml_setup_stubs(struct mm_struct *mm); extern void arch_exit_mmap(struct mm_struct *mm); #define deactivate_mm(tsk,mm) do { } while (0) @@ -23,7 +23,9 @@ static inline void activate_mm(struct mm_struct *old, struct mm_struct *new) * when the new ->mm is used for the first time. */ __switch_mm(&new->context.id); - arch_dup_mmap(old, new); + down_write(&new->mmap_sem); + uml_setup_stubs(new); + up_write(&new->mmap_sem); } static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, @@ -39,6 +41,11 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, } } +static inline void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) +{ + uml_setup_stubs(mm); +} + static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) { diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c index db2ef42..4947b31 100644 --- a/arch/um/kernel/skas/mmu.c +++ b/arch/um/kernel/skas/mmu.c @@ -101,7 +101,7 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm) return ret; } -void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) +void uml_setup_stubs(struct mm_struct *mm) { struct page **pages; int err, ret; -- 2.7.4