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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2DFACC38A2D for ; Mon, 24 Oct 2022 11:47:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231663AbiJXLrF (ORCPT ); Mon, 24 Oct 2022 07:47:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230219AbiJXLpK (ORCPT ); Mon, 24 Oct 2022 07:45:10 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6726F1CB21; Mon, 24 Oct 2022 04:42:33 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B005AB8115E; Mon, 24 Oct 2022 11:42:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12C3DC433C1; Mon, 24 Oct 2022 11:42:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666611731; bh=K1rFR5/EOtnA9W1cWqlMP/EGYwolFkZjTI4Y9jSRlQc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uv7jn1bxZkk5IONjvbFm8tAomZzknAkiwIraEl9fFKGGDMHDRGV8X254MeCDABM/w 62BR8RA2lPeKNrs6YRwaNuUCfYlsWKzXJmhIU8/kdQJCzEkMmBvKSNz2tbicnx0FZK Y51FVgitOuoLE9X90KScH44IPfUIVW1bJz9m03t0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Nuno=20S=C3=A1?= , Jonathan Cameron , Sasha Levin Subject: [PATCH 4.9 090/159] iio: inkern: only release the device node when done with it Date: Mon, 24 Oct 2022 13:30:44 +0200 Message-Id: <20221024112952.701629645@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024112949.358278806@linuxfoundation.org> References: <20221024112949.358278806@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nuno Sá [ Upstream commit 79c3e84874c7d14f04ad58313b64955a0d2e9437 ] 'of_node_put()' can potentially release the memory pointed to by 'iiospec.np' which would leave us with an invalid pointer (and we would still pass it in 'of_xlate()'). Note that it is not guaranteed for the of_node lifespan to be attached to the device (to which is attached) lifespan so that there is (even though very unlikely) the possibility for the node to be freed while the device is still around. Thus, as there are indeed some of_xlate users which do access the node, a race is indeed possible. As such, we can only release the node after we are done with it. Fixes: 17d82b47a215d ("iio: Add OF support") Signed-off-by: Nuno Sá Link: https://lore.kernel.org/r/20220715122903.332535-2-nuno.sa@analog.com Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin --- drivers/iio/inkern.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c index 218cf4567ab5..13be4c8d7fd3 100644 --- a/drivers/iio/inkern.c +++ b/drivers/iio/inkern.c @@ -139,9 +139,10 @@ static int __of_iio_channel_get(struct iio_channel *channel, idev = bus_find_device(&iio_bus_type, NULL, iiospec.np, iio_dev_node_match); - of_node_put(iiospec.np); - if (idev == NULL) + if (idev == NULL) { + of_node_put(iiospec.np); return -EPROBE_DEFER; + } indio_dev = dev_to_iio_dev(idev); channel->indio_dev = indio_dev; @@ -149,6 +150,7 @@ static int __of_iio_channel_get(struct iio_channel *channel, index = indio_dev->info->of_xlate(indio_dev, &iiospec); else index = __of_iio_simple_xlate(indio_dev, &iiospec); + of_node_put(iiospec.np); if (index < 0) goto err_put; channel->channel = &indio_dev->channels[index]; -- 2.35.1