Christophe Leroy <christophe.leroy@xxxxxxxxxx> writes:
> gup_hugepte() reads hugepage table entries, it can't read
> them directly, huge_ptep_get() must be used.
>
> Fixes: 2ab3a0a02905 ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses")
I see that commit in older versions of linux-next but not in mainline.
In mainline it seems to be: 9e343b467c70 ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses")
I guess it got rebased somewhere along the way.
I fixed it up when applying, and the other two as well.
cheers
> Cc: Will Deacon <will@xxxxxxxxxx>
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> ---
> mm/gup.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index de9e36262ccb..761df4944ef5 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -2425,7 +2425,7 @@ static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
> if (pte_end < end)
> end = pte_end;
>
> - pte = READ_ONCE(*ptep);
> + pte = huge_ptep_get(ptep);
>
> if (!pte_access_permitted(pte, flags & FOLL_WRITE))
> return 0;
> --
> 2.25.0
