On 2025-03-07 at 02:10:12 +0100, Andrey Konovalov wrote: >On Tue, Mar 4, 2025 at 1:31 PM Maciej Wieczor-Retman ><maciej.wieczor-retman@xxxxxxxxx> wrote: >> >> One other question that came to me about how KASAN works, is there some >> mechanism to prevent data races between two threads? In the compiler perhaps? >> >> For example memory is de-allocated and shadow memory is poisoned but some other >> thread was just about to do a shadow memory check and was interrupted? >> >> I've read the kasan/vmalloc.c comments and from them I'd extrapolate that the >> caller needs to make sure there are not data races / memory barriers are in >> place. > >KASAN does nothing to deliberately prevent or detect races. Even if >the race leads to an OOB or UAF, KASAN might not be able to detect it. >But sometimes it does: if poisoned shadow memory values become visible >to the other thread/CPU before it makes a shadow memory value check. Thanks :) I've came up with a theoretical issue for the following dense series that might happen if there is some racing but I'll have to experiment if it actually happens. -- Kind regards Maciej Wieczór-Retman
