Re: [PATCH v4] mm: vmalloc: WARN_ON if mapping size is not PAGE_SIZE aligned

[Uladzislau Rezki <urezki@gmail.com>]

On Fri, Oct 10, 2025 at 11:16:27AM +0530, Dev Jain wrote:
> 
> On 10/10/25 7:13 am, Yadong Qi wrote:
> > In mm/vmalloc.c, the function vmap_pte_range() assumes that the
> > mapping size is aligned to PAGE_SIZE. If this assumption is
> > violated, the loop will become infinite because the termination
> > condition (`addr != end`) will never be met. This can lead to
> > overwriting other VA ranges and/or random pages physically follow
> > the page table.
> > 
> > It's the caller's responsibility to ensure that the mapping size
> > is aligned to PAGE_SIZE. However, the memory corruption is hard
> > to root cause. To identify the programming error in the caller
> > easier, check whether the mapping size is PAGE_SIZE aligned with
> > WARN_ON_ONCE().
> > 
> > Signed-off-by: Yadong Qi <yadong.qi@linux.alibaba.com>
> > Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com>
> > ---
> 
> This should work.
> 
> Reviewed-by: Dev Jain <dev.jain@arm.com>
> 
LGTM,

Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

--
Uladzislau Rezki