From nobody Wed Apr 8 15:52:10 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79FBFECAAA1 for ; Sun, 30 Oct 2022 15:45:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229832AbiJ3Po7 (ORCPT ); Sun, 30 Oct 2022 11:44:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44508 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229717AbiJ3Pox (ORCPT ); Sun, 30 Oct 2022 11:44:53 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C85FB1D8 for ; Sun, 30 Oct 2022 08:44:52 -0700 (PDT) Received: from dimapc.. (unknown [109.252.112.196]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dmitry.osipenko) by madras.collabora.co.uk (Postfix) with ESMTPSA id 539C7660225F; Sun, 30 Oct 2022 15:44:49 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1667144690; bh=9L1UGeJdnkFYaRnE59XJ8gv48CnIdhLcIsE2uZ/nI0w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NrgMQ4JJcS/wCdnXA8AG/2ltnRc/459pzQVz+tPEzTYMw+l7wUlkqJ3gZn7BQsjRv 9EqSxbTZQnHVfP80TN7xvKFBhY/gqWfvUuzxwqLZJzFlY/fllOOfADR9n2UjVY/Ovw vC2W3JH7CUfTxnn47rZPq8ltpqZkp44vY1VcNNd7WV7ugzd5Wn+KLCw30/TaqhP6IR BTFkOYacsIhlK0YpHKh2lzNCdwaG/NrrN6UBYAaGFaRd+fLrIv1r9kp7pMPoIXazJr hYSBvQpvrwDbcLRpxvHRM31eY6ni/XCZvj9Zmntx78pHz5itR4y+dreooXnjBow/ia PZ8gz0SH1PJQg== From: Dmitry Osipenko To: Maarten Lankhorst , Maxime Ripard , Sumit Semwal , Thomas Zimmermann , =?UTF-8?q?Christian=20K=C3=B6nig?= , David Airlie , Daniel Vetter , noralf@tronnes.org, Dan Carpenter Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/2] dma-buf: Make locking consistent in dma_buf_detach() Date: Sun, 30 Oct 2022 18:44:11 +0300 Message-Id: <20221030154412.8320-2-dmitry.osipenko@collabora.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221030154412.8320-1-dmitry.osipenko@collabora.com> References: <20221030154412.8320-1-dmitry.osipenko@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The dma_buf_detach() locks attach->dmabuf->resv and then unlocks dmabuf->resv, which could be a two different locks from a static code checker perspective. In particular this triggers Smatch to report the "double unlock" error. Make the locking pointers consistent. Reported-by: Dan Carpenter Reviewed-by: Christian K=C3=B6nig Link: https://lore.kernel.org/dri-devel/Y1fLfsccW3AS%2Fo+%2F@kili/ Fixes: 809d9c72c2f8 ("dma-buf: Move dma_buf_attach() to dynamic locking spe= cification") Signed-off-by: Dmitry Osipenko --- drivers/dma-buf/dma-buf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index c40d72d318fd..13bfd2d09c56 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -995,10 +995,10 @@ static void __unmap_dma_buf(struct dma_buf_attachment= *attach, */ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *att= ach) { - if (WARN_ON(!dmabuf || !attach)) + if (WARN_ON(!dmabuf || !attach || dmabuf !=3D attach->dmabuf)) return; =20 - dma_resv_lock(attach->dmabuf->resv, NULL); + dma_resv_lock(dmabuf->resv, NULL); =20 if (attach->sgt) { =20 --=20 2.37.3