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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 B4425C282CD for ; Wed, 30 Jan 2019 04:05:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 83D622080F for ; Wed, 30 Jan 2019 04:05:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548821109; bh=xLqJsDJUKnn/7LZk2z/3AiVtQK7Cur8CP8DzZVja8bQ=; h=From:To:CC:Subject:Date:In-Reply-To:References:List-ID:From; b=S4ouDA/tCMuk5GR1W2hBg+J4OaXwnk2kgyUaqfCx1fwW+kOxhVX/kBXQn8ourZ4QO acCE6iNO7t8bEICXdYfBmotFYhDDXlKVDp8+nq7AwvxZCa0jDkRg1MZi0Z2ljUhQ2Q iH2WCWgkHmb7PoQCS508Y4V1BbgfWtvaRsxnaOCg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730126AbfA3EFI convert rfc822-to-8bit (ORCPT ); Tue, 29 Jan 2019 23:05:08 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:56554 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727672AbfA3EFI (ORCPT ); Tue, 29 Jan 2019 23:05:08 -0500 Received: from pps.filterd (m0001255.ppops.net [127.0.0.1]) by mx0b-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x0U3vP4d007980 for ; Tue, 29 Jan 2019 20:05:06 -0800 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0b-00082601.pphosted.com with ESMTP id 2qayjj0txk-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Tue, 29 Jan 2019 20:05:06 -0800 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::125) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1531.3; Tue, 29 Jan 2019 20:05:04 -0800 Received: by devbig007.ftw2.facebook.com (Postfix, from userid 572438) id 86493760C91; Tue, 29 Jan 2019 20:05:02 -0800 (PST) Smtp-Origin-Hostprefix: devbig From: Alexei Starovoitov Smtp-Origin-Hostname: devbig007.ftw2.facebook.com To: CC: , , , , , Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf-next 2/4] bpf: fix lockdep false positive in stackmap Date: Tue, 29 Jan 2019 20:04:56 -0800 Message-ID: <20190130040458.2544340-3-ast@kernel.org> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20190130040458.2544340-1-ast@kernel.org> References: <20190130040458.2544340-1-ast@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-01-30_03:,, signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Lockdep warns about false positive: [ 11.211460] ------------[ cut here ]------------ [ 11.211936] DEBUG_LOCKS_WARN_ON(depth <= 0) [ 11.211985] WARNING: CPU: 0 PID: 141 at ../kernel/locking/lockdep.c:3592 lock_release+0x1ad/0x280 [ 11.213134] Modules linked in: [ 11.213413] CPU: 0 PID: 141 Comm: systemd-journal Not tainted 5.0.0-rc3-00018-g2fa53f892422-dirty #476 [ 11.214191] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 [ 11.214954] RIP: 0010:lock_release+0x1ad/0x280 [ 11.217036] RSP: 0018:ffff88813ba03f50 EFLAGS: 00010086 [ 11.217516] RAX: 000000000000001f RBX: ffff8881378d8000 RCX: 0000000000000000 [ 11.218179] RDX: ffffffff810d3e9e RSI: 0000000000000001 RDI: ffffffff810d3eb3 [ 11.218851] RBP: ffff8881393e2b08 R08: 0000000000000002 R09: 0000000000000000 [ 11.219504] R10: 0000000000000000 R11: ffff88813ba03d9d R12: ffffffff8118dfa2 [ 11.220162] R13: 0000000000000086 R14: 0000000000000000 R15: 0000000000000000 [ 11.220717] FS: 00007f3c8cf35780(0000) GS:ffff88813ba00000(0000) knlGS:0000000000000000 [ 11.221348] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 11.221822] CR2: 00007f5825d92080 CR3: 00000001378c8005 CR4: 00000000003606f0 [ 11.222381] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 11.222951] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 11.223508] Call Trace: [ 11.223705] [ 11.223874] ? __local_bh_enable+0x7a/0x80 [ 11.224199] up_read+0x1c/0xa0 [ 11.224446] do_up_read+0x12/0x20 [ 11.224713] irq_work_run_list+0x43/0x70 [ 11.225030] irq_work_run+0x26/0x50 [ 11.225310] smp_irq_work_interrupt+0x57/0x1f0 [ 11.225662] irq_work_interrupt+0xf/0x20 since rw_semaphore is released in a different task vs task that locked the sema. It is expected behavior. Silence the warning by using up_read_non_owner(). Fixes: bae77c5eb5b2 ("bpf: enable stackmap with build_id in nmi context") Acked-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov --- kernel/bpf/stackmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index d43b14535827..4b79e7c251e5 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -44,7 +44,7 @@ static void do_up_read(struct irq_work *entry) struct stack_map_irq_work *work; work = container_of(entry, struct stack_map_irq_work, irq_work); - up_read(work->sem); + up_read_non_owner(work->sem); work->sem = NULL; } -- 2.20.0