Re: [PATCH] zsmalloc: calling zs_map_object() from irq is a bug

From: Minchan Kim
Date: Wed Sep 20 2017 - 02:47:46 EST

On Wed, Sep 20, 2017 at 03:39:41PM +0900, Sergey Senozhatsky wrote:
> Use BUG_ON(in_interrupt()) in zs_map_object(). Calling this
> function from IRQ is a bug, because we use per-CPU mappings
> and interrupt may corrupt those buffers.
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>

IMHO, corruption the buffer would be not enough to be a BUG_ON
which stop the system fully so user loses any chances to shut
down smooth/hunt it down.

More serious thing of our case is that it can leak other user's
data by overwriting, which is more concern I am thinking now.


Acked-by: Minchan Kim <minchan@xxxxxxxxxx>