Messages in this thread | | | Subject | Re: [PATCH] mm: Fix potential pte_unmap_unlock pte error | From | Miaohe Lin <> | Date | Mon, 25 Jan 2021 10:04:19 +0800 |
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Hi: On 2021/1/24 10:01, Andrew Morton wrote: > 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. > > . >
Sounds reasonable. Many thanks for doing this!
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