Re: [PATCH 7/6] mm: pagewalk: add back missing variable initializations

From: Nathan Chancellor
Date: Wed Aug 24 2022 - 11:08:16 EST


On Wed, Aug 24, 2022 at 01:00:11PM +0200, Rolf Eike Beer wrote:
> These initializations accidentially got lost during refactoring.
>
> The first one can't actually be used without initialization, because
> walk_p4d_range() is only called when one of the 4 callbacks is set, but relying
> on this seems fragile.
>
> Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Signed-off-by: Rolf Eike Beer <eb@xxxxxxxxx>

Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>

> ---
> mm/pagewalk.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> Looks like my testing had just the right callbacks set so I never hit this. In
> case you want to have this squashed into the original one just drop me a note
> and I'll redo the whole series.
>
> diff --git a/mm/pagewalk.c b/mm/pagewalk.c
> index d8be8a30b272..22e4bcca9bee 100644
> --- a/mm/pagewalk.c
> +++ b/mm/pagewalk.c
> @@ -223,7 +223,7 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
>
> p4d = p4d_offset(pgd, addr);
> do {
> - int err;
> + int err = 0;
>
> next = p4d_addr_end(addr, end);
> if (p4d_none_or_clear_bad(p4d)) {
> @@ -262,7 +262,7 @@ static int walk_pgd_range(unsigned long addr, unsigned long end,
> else
> pgd = pgd_offset(walk->mm, addr);
> do {
> - int err;
> + int err = 0;
>
> next = pgd_addr_end(addr, end);
> if (pgd_none_or_clear_bad(pgd)) {
> @@ -308,7 +308,7 @@ static int walk_hugetlb_range(unsigned long addr, unsigned long end,
> const struct mm_walk_ops *ops = walk->ops;
>
> for (; addr < end; addr = next) {
> - int err;
> + int err = 0;
> pte_t *pte = huge_pte_offset(walk->mm, addr & hmask, sz);
>
> next = hugetlb_entry_end(h, addr, end);
> --
> 2.37.2
>
> --
> Rolf Eike Beer, emlix GmbH, https://www.emlix.com
> Fon +49 551 30664-0, Fax +49 551 30664-11
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>
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