Messages in this thread Patch in this message | | | Subject | [PATCH] ppc64: Fix possible race with set_pte on a present PTE | From | Benjamin Herrenschmidt <> | Date | Mon, 24 May 2004 13:29:53 +1000 |
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(RESENT)
There is a subtle race which can cause set_pte to be called on ppc64 on a PTE that is already present (that normally doesn't happen for us) and which itself, in the proper race condition, can trigger a duplicate hash entry to be added to the hash table (very bad).
This fixes it by making sure we trigger the actual flush of the batch whenever set_pte is called on a present PTE, before putting the new PTE in.
===== include/asm-ppc64/pgtable.h 1.32 vs edited ===== --- 1.32/include/asm-ppc64/pgtable.h Fri Apr 9 03:30:57 2004 +++ edited/include/asm-ppc64/pgtable.h Thu May 20 15:47:40 2004 @@ -396,8 +396,10 @@ */ static inline void set_pte(pte_t *ptep, pte_t pte) { - if (pte_present(*ptep)) + if (pte_present(*ptep)) { pte_clear(ptep); + flush_tlb_pending(); + } *ptep = __pte(pte_val(pte)) & ~_PAGE_HPTEFLAGS; }
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