Re: [PATCH v2] mm: vmscan: add VM_BUG_ON on illegal return values from scan_objects

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, May 21, 2013 at 10:13 AM, Oskar Andero
<oskar.andero@xxxxxxxxxxxxxx> wrote:
> Add a VM_BUG_ON to catch any illegal value from the shrinkers. It's a
> potential bug if scan_objects returns a negative other than -1 and
> would lead to undefined behaviour.
>
> Cc: Glauber Costa <glommer@xxxxxxxxxx>
> Cc: Dave Chinner <dchinner@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Oskar Andero <oskar.andero@xxxxxxxxxxxxxx>
> ---
>  mm/vmscan.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 6bac41e..63fec86 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -293,6 +293,7 @@ shrink_slab_one(struct shrinker *shrinker, struct shrink_control *shrinkctl,
>                 ret = shrinker->scan_objects(shrinker, shrinkctl);
>                 if (ret == -1)
>                         break;
> +               VM_BUG_ON(ret < -1);

It seems to me relaxing the shrinker API restrictions and changing the
"ret == -1" to "ret < 0" would be a much more robust approach...

>                 freed += ret;
>
>                 count_vm_events(SLABS_SCANNED, nr_to_scan);
> --
> 1.8.1.5
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>




[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]