Re: [PATCH 1/2] mm: add GFP mask param to strndup_user

On Sat, Aug 15, 2020 at 11:42:10PM +0100, Al Viro wrote:

On Sat, Aug 15, 2020 at 11:23:43AM -0700, Pascal Bouchareine wrote:

quoted

Let caller specify allocation.
Preserve existing calls with GFP_USER.

Bloody bad idea, unless you slap a BUG_ON(flags & GFP_ATOMIC) on it,
to make sure nobody tries _that_.  Note that copying from userland
is an inherently blocking operation, and this interface invites
just that.

What do you need that flag for, anyway?

You need it for kmem accounting.