From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 126C4C433EF for ; Thu, 9 Sep 2021 13:34:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 94A3B611C7 for ; Thu, 9 Sep 2021 13:34:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 94A3B611C7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id C7AEF900002; Thu, 9 Sep 2021 09:34:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C2AD46B0072; Thu, 9 Sep 2021 09:34:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B1924900002; Thu, 9 Sep 2021 09:34:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0093.hostedemail.com [216.40.44.93]) by kanga.kvack.org (Postfix) with ESMTP id 9A0456B006C for ; Thu, 9 Sep 2021 09:34:11 -0400 (EDT) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 4979C180C4E54 for ; Thu, 9 Sep 2021 13:34:11 +0000 (UTC) X-FDA: 78568128702.13.C02CBD5 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf07.hostedemail.com (Postfix) with ESMTP id F3EDC1000098 for ; Thu, 9 Sep 2021 13:34:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=LymjhqFPErmB71T4SArEOYRvy1OFs+5watamyFLdueY=; b=MSZvGW8r0K42nd6yod4edEfhnU qhI8OKS0XfBwLMJaSb8OZVJwlqheoZAICnYskvYSDLyA6lkoutv353tGnHAu4u0U/qyV6V4JCdYT0 Vo28SX7QGuzqw3q5t4b+0pKukv9+tIaVf0pEq7QG8XWjzEIwW1Skpttgb6Bz12CLVcz10POkHxqOq d1gGlMO5wbUkYS91AH5KQkKbi522TNfHfZcBnU/oeajAXqrU9mtnzxORBW3tqILVDsfD8bqssqEGm Wi5ZWKvq2tHwlLGyd/sPNykHfEo5kLRuP4ea3ii9eUrrkmT0Ejv202oHmQ+5wFLeWBlt4ooY6+aIw AuwPycmA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mOKB1-009xTj-Jh; Thu, 09 Sep 2021 13:33:27 +0000 Date: Thu, 9 Sep 2021 14:33:15 +0100 From: Matthew Wilcox To: Yonghong Song Cc: bpf@vger.kernel.org, linux-mm@kvack.org, Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Luigi Rizzo , Jason Gunthorpe Subject: Re: [PATCH bpf-next v4] bpf: fix lockdep warning triggered by stack_map_get_build_id_offset() Message-ID: References: <20210909060245.2966358-1-yhs@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210909060245.2966358-1-yhs@fb.com> Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=MSZvGW8r; spf=none (imf07.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: F3EDC1000098 X-Stat-Signature: 91qycuw88u4j6hh357iekc9wgde881yb X-HE-Tag: 1631194450-226295 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 Wed, Sep 08, 2021 at 11:02:45PM -0700, Yonghong Song wrote: > @@ -204,9 +204,10 @@ static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs, > } > > if (!work) { > - mmap_read_unlock_non_owner(current->mm); > + mmap_read_unlock(current->mm); > } else { > work->mm = current->mm; > + rwsem_release(¤t->mm->mmap_lock.dep_map, _RET_IP_); > irq_work_queue(&work->irq_work); This needs a comment before the rwsem_release(). Something like: /* * The lock will be released once we're out of interrupt * context. Tell lockdep that we've released it now so * it doesn't complain that we forgot to release it. */