[PATCH] mm/vmalloc: bail out early on invalid page_shift in __vmap_pages_range_noflush()

[PATCH] mm/vmalloc: bail out early on invalid page_shift in __vmap_pages_range_noflush()

[Wen Jiang]

__vmap_pages_range_noflush() currently only warns when page_shift is
smaller than PAGE_SHIFT, then continues with the invalid shift. Return
-EINVAL instead so the bogus argument is caught immediately.

Suggested-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
---
 mm/vmalloc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index bea9f76ed7e7..838c8e0ccfe9 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -684,7 +684,8 @@ int __vmap_pages_range_noflush(unsigned long addr, unsigned long end,
 {
 	unsigned int i, nr = (end - addr) >> PAGE_SHIFT;
 
-	WARN_ON(page_shift < PAGE_SHIFT);
+	if (WARN_ON_ONCE(page_shift < PAGE_SHIFT))
+		return -EINVAL;
 
 	if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMALLOC) ||
 			page_shift == PAGE_SHIFT)
-- 
2.34.1

Re: [PATCH] mm/vmalloc: bail out early on invalid page_shift in __vmap_pages_range_noflush()

[Barry Song]

On Sat, Oct 3, 2026 at 5:05 PM Wen Jiang <jiangwenxiaomi@gmail.com> wrote:
>
> __vmap_pages_range_noflush() currently only warns when page_shift is
> smaller than PAGE_SHIFT, then continues with the invalid shift. Return
> -EINVAL instead so the bogus argument is caught immediately.
>
> Suggested-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>

I have checked this carefully and confirmed that this is a correct cleanup.

However, when I applied your patch, I noticed that the author and
Signed-off-by do not match.

Author: Wen Jiang <jiangwenxiaomi@gmail.com>
Date:   Sat Oct 3 17:04:30 2026 +0800

    mm/vmalloc: bail out early on invalid page_shift in
__vmap_pages_range_noflush()
    ...
    Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>


So please send a v2 to fix this, and feel free to include:

Reviewed-by: Barry Song <baohua@kernel.org>

Best Regards
Barry

Re: [PATCH] mm/vmalloc: bail out early on invalid page_shift in __vmap_pages_range_noflush()

[Uladzislau Rezki]

On Sat, Oct 03, 2026 at 06:02:37PM +0800, Barry Song wrote:
> On Sat, Oct 3, 2026 at 5:05 PM Wen Jiang <jiangwenxiaomi@gmail.com> wrote:
> >
> > __vmap_pages_range_noflush() currently only warns when page_shift is
> > smaller than PAGE_SHIFT, then continues with the invalid shift. Return
> > -EINVAL instead so the bogus argument is caught immediately.
> >
> > Suggested-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> > Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
> 
> I have checked this carefully and confirmed that this is a correct cleanup.
> 
> However, when I applied your patch, I noticed that the author and
> Signed-off-by do not match.
> 
> Author: Wen Jiang <jiangwenxiaomi@gmail.com>
> Date:   Sat Oct 3 17:04:30 2026 +0800
> 
>     mm/vmalloc: bail out early on invalid page_shift in
> __vmap_pages_range_noflush()
>     ...
>     Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
> 
> 
> So please send a v2 to fix this, and feel free to include:
> 
> Reviewed-by: Barry Song <baohua@kernel.org>
> 
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

--
Uladzislau Rezki

Re: [PATCH] mm/vmalloc: bail out early on invalid page_shift in __vmap_pages_range_noflush()

[Wen Jiang]

> I have checked this carefully and confirmed that this is a correct cleanup.
>
> However, when I applied your patch, I noticed that the author and
> Signed-off-by do not match.
>
> Author: Wen Jiang <jiangwenxiaomi@gmail.com>
> Date:   Sat Oct 3 17:04:30 2026 +0800
>
>     mm/vmalloc: bail out early on invalid page_shift in
> __vmap_pages_range_noflush()
>     ...
>     Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
>

Hi Barry,

I'll send a v2 separately with jiangwen6@xiaomi.com
for both the author and Signed-off-by.

Thanks,
Wen