From 250cf776f74b5932a1977d0489cae9206e2351dd Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Tue, 28 Oct 2008 11:10:15 +0100 Subject: [S390] pgtables: Fix race in enable_sie vs. page table ops The current enable_sie code sets the mm->context.pgstes bit to tell dup_mm that the new mm should have extended page tables. This bit is also used by the s390 specific page table primitives to decide about the page table layout - which means context.pgstes has two meanings. This can cause any kind of bugs. For example - e.g. shrink_zone can call ptep_clear_flush_young while enable_sie is running. ptep_clear_flush_young will test for context.pgstes. Since enable_sie changed that value of the old struct mm without changing the page table layout ptep_clear_flush_young will do the wrong thing. The solution is to split pgstes into two bits - one for the allocation - one for the current state Signed-off-by: Christian Borntraeger Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/mmu.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/s390/include/asm/mmu.h') diff --git a/arch/s390/include/asm/mmu.h b/arch/s390/include/asm/mmu.h index 5dd5e7b3476f..d2b4ff831477 100644 --- a/arch/s390/include/asm/mmu.h +++ b/arch/s390/include/asm/mmu.h @@ -7,7 +7,8 @@ typedef struct { unsigned long asce_bits; unsigned long asce_limit; int noexec; - int pgstes; + int has_pgste; /* The mmu context has extended page tables */ + int alloc_pgste; /* cloned contexts will have extended page tables */ } mm_context_t; #endif -- cgit v1.2.3