* [PATCH] vmalloc: Fix NULL pointer dereference in is_vm_area_hugepages()
@ 2026-05-29 1:41 Hui Zhu
2026-05-29 4:54 ` Dev Jain
0 siblings, 1 reply; 3+ messages in thread
From: Hui Zhu @ 2026-05-29 1:41 UTC (permalink / raw)
To: Andrew Morton, Uladzislau Rezki, Nicholas Piggin, linux-mm,
linux-kernel
Cc: Hui Zhu
From: Hui Zhu <zhuhui@kylinos.cn>
find_vm_area() can return NULL if the given address is not a valid
vmalloc area. Check the return value before dereferencing it to avoid
a kernel crash.
Fixes: 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings")
Signed-off-by: Hui Zhu <zhuhui@kylinos.cn>
---
include/linux/vmalloc.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 3b02c0c6b371..d87dc7f77f4e 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -265,7 +265,9 @@ static inline bool is_vm_area_hugepages(const void *addr)
* allocated in the vmalloc layer.
*/
#ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC
- return find_vm_area(addr)->page_order > 0;
+ struct vm_struct *area = find_vm_area(addr);
+
+ return area && area->page_order > 0;
#else
return false;
#endif
--
2.43.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] vmalloc: Fix NULL pointer dereference in is_vm_area_hugepages()
2026-05-29 1:41 [PATCH] vmalloc: Fix NULL pointer dereference in is_vm_area_hugepages() Hui Zhu
@ 2026-05-29 4:54 ` Dev Jain
2026-06-01 9:29 ` Uladzislau Rezki
0 siblings, 1 reply; 3+ messages in thread
From: Dev Jain @ 2026-05-29 4:54 UTC (permalink / raw)
To: Hui Zhu, Andrew Morton, Uladzislau Rezki, Nicholas Piggin,
linux-mm, linux-kernel
Cc: Hui Zhu
On 29/05/26 7:11 am, Hui Zhu wrote:
> From: Hui Zhu <zhuhui@kylinos.cn>
>
> find_vm_area() can return NULL if the given address is not a valid
> vmalloc area. Check the return value before dereferencing it to avoid
> a kernel crash.
>
> Fixes: 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings")
> Signed-off-by: Hui Zhu <zhuhui@kylinos.cn>
> ---
I think this makes sense from API PoV.
Reviewed-by: Dev Jain <dev.jain@arm.com>
> include/linux/vmalloc.h | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
> index 3b02c0c6b371..d87dc7f77f4e 100644
> --- a/include/linux/vmalloc.h
> +++ b/include/linux/vmalloc.h
> @@ -265,7 +265,9 @@ static inline bool is_vm_area_hugepages(const void *addr)
> * allocated in the vmalloc layer.
> */
> #ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC
> - return find_vm_area(addr)->page_order > 0;
> + struct vm_struct *area = find_vm_area(addr);
> +
> + return area && area->page_order > 0;
> #else
> return false;
> #endif
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] vmalloc: Fix NULL pointer dereference in is_vm_area_hugepages()
2026-05-29 4:54 ` Dev Jain
@ 2026-06-01 9:29 ` Uladzislau Rezki
0 siblings, 0 replies; 3+ messages in thread
From: Uladzislau Rezki @ 2026-06-01 9:29 UTC (permalink / raw)
To: Hui Zhu
Cc: Hui Zhu, Andrew Morton, Uladzislau Rezki, Nicholas Piggin,
linux-mm, linux-kernel, Hui Zhu
On Fri, May 29, 2026 at 10:24:12AM +0530, Dev Jain wrote:
>
>
> On 29/05/26 7:11 am, Hui Zhu wrote:
> > From: Hui Zhu <zhuhui@kylinos.cn>
> >
> > find_vm_area() can return NULL if the given address is not a valid
> > vmalloc area. Check the return value before dereferencing it to avoid
> > a kernel crash.
> >
> > Fixes: 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings")
> > Signed-off-by: Hui Zhu <zhuhui@kylinos.cn>
> > ---
>
> I think this makes sense from API PoV.
>
> Reviewed-by: Dev Jain <dev.jain@arm.com>
>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
--
Uladzislau Rezki
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-05-29 1:41 [PATCH] vmalloc: Fix NULL pointer dereference in is_vm_area_hugepages() Hui Zhu
2026-05-29 4:54 ` Dev Jain
2026-06-01 9:29 ` Uladzislau Rezki
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