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

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

[mdshahid03]

From: Mohammad Shahid <mdshahid03@gmail.com>

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.

Signed-off-by: Mohammad Shahid <mdshahid03@gmail.com>
---
 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

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

[Michael Kelley]

From: mdshahid03@gmail.com <mdshahid03@gmail.com> 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@outlook.com>

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

> 
> Signed-off-by: Mohammad Shahid <mdshahid03@gmail.com>
> ---
>  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
> 

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

[Wei Liu]

On Sun, Nov 01, 2026 at 10:41:05PM +0000, Michael Kelley wrote:
> From: mdshahid03@gmail.com <mdshahid03@gmail.com> 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@outlook.com>
> 
> [1] https://lore.kernel.org/lkml/202603101143.qUL1R1iy-lkp@intel.com/
> [2] https://lore.kernel.org/lkml/202610080503.ivDF5iYX-lkp@intel.com/

Applied. Thanks.

Wei