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dkim=pass header.d=google.com header.s=20210112 header.b=dtquUVtE; spf=pass (imf22.hostedemail.com: domain of elver@google.com designates 209.85.219.176 as permitted sender) smtp.mailfrom=elver@google.com; dmarc=pass (policy=reject) header.from=google.com X-HE-Tag: 1659558566-676559 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 2 Aug 2022 at 22:45, Andrey Konovalov wrote: > > On Thu, Jul 21, 2022 at 10:41 PM Andrey Konovalov wrote: > > > > On Tue, Jul 19, 2022 at 1:41 PM Marco Elver wrote: > > > > > > > + for (u64 i = pos - 1; i != pos - 1 - KASAN_STACK_RING_SIZE; i--) { > > > > + if (alloc_found && free_found) > > > > + break; > > > > + > > > > + entry = &stack_ring.entries[i % KASAN_STACK_RING_SIZE]; > > > > + > > > > + /* Paired with smp_store_release() in save_stack_info(). */ > > > > + ptr = (void *)smp_load_acquire(&entry->ptr); > > > > + > > > > + if (kasan_reset_tag(ptr) != info->object || > > > > + get_tag(ptr) != get_tag(info->access_addr)) > > > > + continue; > > > > + > > > > + pid = READ_ONCE(entry->pid); > > > > + stack = READ_ONCE(entry->stack); > > > > + is_free = READ_ONCE(entry->is_free); > > > > + > > > > + /* Try detecting if the entry was changed while being read. */ > > > > + smp_mb(); > > > > + if (ptr != (void *)READ_ONCE(entry->ptr)) > > > > + continue; > > > > > > I thought the re-validation is no longer needed because of the rwlock > > > protection? > > > > Oh, yes, forgot to remove this. Will either do in v3 if there are more > > things to fix, or will just send a small fix-up patch if the rest of > > the series looks good. > > > > > The rest looks fine now. > > > > Thank you, Marco! > > Hi Marco, > > I'm thinking of sending a v3. > > Does your "The rest looks fine now" comment refer only to this patch > or to the whole series? If it's the former, could you PTAL at the > other patches? I just looked again. Apart from the comments I just sent, overall it looks fine (whole series). Does test_kasan exercise the ring wrapping around? One thing that might be worth doing is adding a multi-threaded stress test, where you have 2+ threads doing lots of allocations, frees, and generating reports.