RE: [PATCH] x86/hyperv: use pointed-to type size for page table offsets

[Michael Kelley]

From: mdshahid03@xxxxxxxxx <mdshahid03@xxxxxxxxx> Sent: Sunday, November 1, 2026 1:21 AM
> 
> The Hyper-V crash trampoline code calculated page table entry
> offsets using sizeof() on pointer variables.
> 
> Use sizeof(*ptr) instead to calculates the size of the
> pointed-to page table entry.
> 
> This makes entry size explicit and avoids relying on the
> pointer size matching the page table entry size.
> 
> This issue was reported by Coccinelle script noderef.cocci.

FWIW, this issue was also reported by the kernel test robot.
See [1] & [2]. So you should probably add "Reported-by:" and
"Closes: " tags for those reports.

In any case, the fix looks good to me.

Reviewed-by: Michael Kelley <mhklinux@xxxxxxxxxxx>

[1] https://lore.kernel.org/lkml/202603101143.qUL1R1iy-lkp@xxxxxxxxx/
[2] https://lore.kernel.org/lkml/202610080503.ivDF5iYX-lkp@xxxxxxxxx/

> 
> Signed-off-by: Mohammad Shahid <mdshahid03@xxxxxxxxx>
> ---
>  arch/x86/hyperv/hv_crash.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/hyperv/hv_crash.c b/arch/x86/hyperv/hv_crash.c
> index 5ffcc23255de..810eb1a4a0a2 100644
> --- a/arch/x86/hyperv/hv_crash.c
> +++ b/arch/x86/hyperv/hv_crash.c
> @@ -512,20 +512,20 @@ static void hv_crash_build_tramp_pt(void)
>  	pte_t *pte;
>  	u64 pa, addr = trampoline_pa;
> 
> -	p4d = hv_crash_ptpgs[0] + pgd_index(addr) * sizeof(p4d);
> +	p4d = hv_crash_ptpgs[0] + pgd_index(addr) * sizeof(*p4d);
>  	pa = virt_to_phys(hv_crash_ptpgs[1]);
>  	set_p4d(p4d, __p4d(_PAGE_TABLE | pa));
>  	p4d->p4d &= ~(_PAGE_NX);	/* enable execute */
> 
> -	pud = hv_crash_ptpgs[1] + pud_index(addr) * sizeof(pud);
> +	pud = hv_crash_ptpgs[1] + pud_index(addr) * sizeof(*pud);
>  	pa = virt_to_phys(hv_crash_ptpgs[2]);
>  	set_pud(pud, __pud(_PAGE_TABLE | pa));
> 
> -	pmd = hv_crash_ptpgs[2] + pmd_index(addr) * sizeof(pmd);
> +	pmd = hv_crash_ptpgs[2] + pmd_index(addr) * sizeof(*pmd);
>  	pa = virt_to_phys(hv_crash_ptpgs[3]);
>  	set_pmd(pmd, __pmd(_PAGE_TABLE | pa));
> 
> -	pte = hv_crash_ptpgs[3] + pte_index(addr) * sizeof(pte);
> +	pte = hv_crash_ptpgs[3] + pte_index(addr) * sizeof(*pte);
>  	set_pte(pte, pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
>  }
> 
> --
> 2.43.0
>