Messages in this thread | | | Date | Sat, 23 Jan 2021 18:01:07 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] mm: Fix potential pte_unmap_unlock pte error |
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On Fri, 22 Jan 2021 16:27:23 +0800 Miaohe Lin <linmiaohe@huawei.com> wrote:
> Hi Andrew: > On 2021/1/14 10:51, Miaohe Lin wrote: > > Hi: > > On 2021/1/11 1:14, Andi Kleen wrote: > >> On Sat, Jan 09, 2021 at 03:01:18AM -0500, Miaohe Lin wrote: > >>> Since commit 42e4089c7890 ("x86/speculation/l1tf: Disallow non privileged > >>> high MMIO PROT_NONE mappings"), when the first pfn modify is not allowed, > >>> we would break the loop with pte unchanged. Then the wrong pte - 1 would > >>> be passed to pte_unmap_unlock. > >> > >> Thanks. > >> > >> While the fix is correct, I'm not sure if it actually is a real bug. Is there > >> any architecture that would do something else than unlocking the underlying > >> page? If it's just the underlying page then it should be always the same > >> page, so no bug. > >> > > > > It's just a theoretical issue via code inspection. > > Should I send a new one without Cc statle or just drop this patch? Thanks.
Your patch makes the code much less scary looking. I added Andi's observation to the changelog, removed the cc:stable and queued it up, thanks.
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