Messages in this thread Patch in this message | | | Subject | [PATCH] 2.4.0-test10-pre6 TLB flush race in establish_pte | From | "Steve Pratt/Austin/IBM" <> | Date | Mon, 30 Oct 2000 15:31:22 -0600 |
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Back in April there were discussions about the race in establish_pte with the flush_tlb before the set_pte. Many options were discussed, but due in part to a concern about S/390 having introduced the code, no patch ever appeared. I talked with Martin Schwidefsky of the S/390 Linux development team and he said that:
>the establish_pte was in fact introduced because of Linux/390. We wanted to use the special S/390 instruction ipte (invalidate page >table entry). In the meantime we found out that we need a lot more changes to be able to use this instruction, so we disabled it again. >Until we have a proper patch you should revoke the establish_pte change if you found it to be faulty. I too think there is a race >condition.
So while there may be a more elegant solution down the road, I would like to see the simple fix put back into 2.4. Here is the patch to essential put the code back to the way it was before the S/390 merge. Patch is against 2.4.0-test10pre6.
--- linux/mm/memory.c Fri Oct 27 15:26:14 2000 +++ linux-2.4.0-test10patch/mm/memory.c Fri Oct 27 15:45:54 2000 @@ -781,8 +781,8 @@ */ static inline void establish_pte(struct vm_area_struct * vma, unsigned long address, pte_t *page_table, pte_t entry) { - flush_tlb_page(vma, address); set_pte(page_table, entry); + flush_tlb_page(vma, address); update_mmu_cache(vma, address, entry); }
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