Re: [PATCH] mm/mmap: Fix fsnotify_mmap_perm() call in vm_mmap_pgoff()

[Dev Jain]

On 03/10/25 9:28 pm, Kiryl Shutsemau wrote:
> From: Kiryl Shutsemau <kas@xxxxxxxxxx>
>
> vm_mmap_pgoff() includes a fsnotify call that allows for pre-content
> hooks on mmap().
>
> The fsnotify_mmap_perm() function takes, among other arguments, an
> offset in the file in the form of loff_t. However, vm_mmap_pgoff() has
> file offset in the form of pgoff. This offset needs to be converted
> before being passed to fsnotify_mmap_perm().
>
> The conversion from pgoff to loff_t is incorrect. The pgoff value needs
> to be shifted left by PAGE_SHIFT to obtain loff_t, not right.
>
> This issue was identified through code inspection.
>
> Signed-off-by: Kiryl Shutsemau <kas@xxxxxxxxxx>
> Fixes: 066e053fe208 ("fsnotify: add pre-content hooks on mmap()")
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
> Cc: Amir Goldstein <amir73il@xxxxxxxxx>
> Cc: Jan Kara <jack@xxxxxxx>
> ---
>   

Reviewed-by: Dev Jain <dev.jain@xxxxxxx>