On Thu, Nov 12, 2020 at 1:55 PM Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > > On Thu, Nov 12, 2020 at 12:53:58PM +0100, Marco Elver wrote: > > On Thu, 12 Nov 2020 at 12:35, Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > > > > > > On Tue, Nov 10, 2020 at 11:20:15PM +0100, Andrey Konovalov wrote: > > > > Hardware tag-based KASAN mode is intended to eventually be used in > > > > production as a security mitigation. Therefore there's a need for finer > > > > control over KASAN features and for an existence of a kill switch. > > > > > > > > This change adds a few boot parameters for hardware tag-based KASAN that > > > > allow to disable or otherwise control particular KASAN features. > > > > > > > > The features that can be controlled are: > > > > > > > > 1. Whether KASAN is enabled at all. > > > > 2. Whether KASAN collects and saves alloc/free stacks. > > > > 3. Whether KASAN panics on a detected bug or not. > > > > > > > > With this change a new boot parameter kasan.mode allows to choose one of > > > > three main modes: > > > > > > > > - kasan.mode=off - KASAN is disabled, no tag checks are performed > > > > - kasan.mode=prod - only essential production features are enabled > > > > - kasan.mode=full - all KASAN features are enabled > > > > > > Alternative naming if we want to avoid "production" (in case someone > > > considers MTE to be expensive in a production system): > > > > > > - kasan.mode=off > > > - kasan.mode=on > > > - kasan.mode=debug > > > > I believe this was what it was in RFC, and we had a long discussion on > > what might be the most intuitive options. Since KASAN is still a > > debugging tool for the most part, an "on" mode might imply we get all > > the debugging facilities of regular KASAN. However, this is not the > > case and misleading. Hence, we decided to be more explicit and avoid > > "on". > > Even better, kasan.mode=fast ;). Well, it uses sync, so technically it's not as fast as it could be with async :)
