From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f200.google.com (mail-qk0-f200.google.com [209.85.220.200]) by kanga.kvack.org (Postfix) with ESMTP id 7180E6B0005 for ; Thu, 31 May 2018 10:30:30 -0400 (EDT) Received: by mail-qk0-f200.google.com with SMTP id c73-v6so20339132qke.2 for ; Thu, 31 May 2018 07:30:30 -0700 (PDT) Received: from a9-92.smtp-out.amazonses.com (a9-92.smtp-out.amazonses.com. [54.240.9.92]) by mx.google.com with ESMTPS id q7-v6si8328185qvq.265.2018.05.31.07.30.29 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 31 May 2018 07:30:29 -0700 (PDT) Date: Thu, 31 May 2018 14:30:29 +0000 From: Christopher Lameter Subject: Re: Can kfree() sleep at runtime? In-Reply-To: <20180531141452.GC30221@bombadil.infradead.org> Message-ID: <01000163b69b6b62-6c5ac940-d6c1-419a-9dc9-697908020c53-000000@email.amazonses.com> References: <30ecafd7-ed61-907b-f924-77fc37dcc753@gmail.com> <20180531140808.GA30221@bombadil.infradead.org> <01000163b68a8026-56fb6a35-040b-4af9-8b73-eb3b4a41c595-000000@email.amazonses.com> <20180531141452.GC30221@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Matthew Wilcox Cc: Jia-Ju Bai , penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, linux-mm@kvack.org, Linux Kernel Mailing List On Thu, 31 May 2018, Matthew Wilcox wrote: > > Freeing a page in the page allocator also was traditionally not sleeping. > > That has changed? > > No. "Your bug" being "The bug in your static analysis tool". It probably > isn't following the data flow correctly (or deeply enough). Well ok this is not going to trigger for kfree(), this is x86 specific and requires CONFIG_DEBUG_PAGEALLOC and a free of a page in a huge page. Ok that is a very contorted situation but how would a static checker deal with that?