Re: [PATCH v1 1/1] pstore/ram: Fix crash when setting number of cpus to an odd number
From: Miko Larsson
Date: Fri Feb 24 2023 - 02:05:13 EST
On Fri, 2023-02-24 at 10:36 +0800, Weichen Chen wrote:
> When the number of cpu cores is adjusted to 7 or other odd numbers,
> the zone size will become an odd number.
> The address of the zone will become:
> addr of zone0 = BASE
> addr of zone1 = BASE + zone_size
> addr of zone2 = BASE + zone_size*2
> ...
> The address of zone1/3/5/7 will be mapped to non-alignment va.
> Eventually crashes will occur when accessing these va.
>
> So, use ALIGN_DOWN() to make sure the zone size is even
> to avoid this bug.
>
> Signed-off-by: Weichen Chen <weichen.chen@xxxxxxxxxxxx>
> ---
> fs/pstore/ram.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> index ade66dbe5f39..fc57ac97e506 100644
> --- a/fs/pstore/ram.c
> +++ b/fs/pstore/ram.c
> @@ -528,6 +528,7 @@ static int ramoops_init_przs(const char *name,
> }
>
> zone_sz = mem_sz / *cnt;
> + zone_sz = ALIGN_DOWN(zone_sz, 2);
> if (!zone_sz) {
> dev_err(dev, "%s zone size == 0\n", name);
> goto fail;
Might want to Cc this to the stable mailing list.
--
~miko