On Thu, 14 Apr 2022 10:59:25 +0800 Zqiang <qiang1.zhang@xxxxxxxxx> wrote: > The kasan_quarantine_remove_cache() is called in kmem_cache_shrink()/ > destroy(), the kasan_quarantine_remove_cache() call is protected by > cpuslock in kmem_cache_destroy(), can ensure serialization with > kasan_cpu_offline(). however the kasan_quarantine_remove_cache() call > is not protected by cpuslock in kmem_cache_shrink(), when CPU going > offline and cache shrink occur at same time, the cpu_quarantine may be > corrupted by interrupt(per_cpu_remove_cache operation). so add > cpu_quarantine offline flags check in per_cpu_remove_cache(). > > ... > >Could we please have some reviewer input here? > --- a/mm/kasan/quarantine.c > +++ b/mm/kasan/quarantine.c > @@ -330,6 +330,8 @@ static void per_cpu_remove_cache(void *arg) > struct cpu_shrink_qlist *sq; > #endif > q = this_cpu_ptr(&cpu_quarantine); > + if (READ_ONCE(q->offline)) > + return; > #ifndef CONFIG_PREEMPT_RT > qlist_move_cache(q, &to_free, cache); > qlist_free_all(&to_free, cache); >It might be helpful to have a little comment which explains why we're doing this? Sorry for late reply, may be add some comment: Ensure the ordering between the writing to q->offline and per_cpu_remove_cache. prevent cpu_quarantine be corrupted by interrupt. Is this OK ? Thanks Zqiang
