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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 EBB67C433FF for ; Mon, 29 Jul 2019 19:34:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B7BEF2070B for ; Mon, 29 Jul 2019 19:34:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564428858; bh=JTbbLUrqNFcBTWKuNtawhRcJdyH9435aAAWqmKj3o2I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2TKeEIBCy/RVOGCgGjLI0YAZO9ej5+SewAsgl4aGFhe1A0bgpCrbrNLtlQCbw4ihR KbEelkqY47bfD/eNg4uGv2i6ODOud3zCUaIDQoZ8vplQcC9qsxhUMqgnMLVp3kuZyT s6wn60hAqshX4m1fDWSeTN0tPmYXFBk0nEiPerSE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388280AbfG2TeR (ORCPT ); Mon, 29 Jul 2019 15:34:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:48584 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388245AbfG2TeL (ORCPT ); Mon, 29 Jul 2019 15:34:11 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 40D9F2171F; Mon, 29 Jul 2019 19:34:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564428850; bh=JTbbLUrqNFcBTWKuNtawhRcJdyH9435aAAWqmKj3o2I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SDA2ejk42ePxmcfd6iyh8zRiGAVBFpMOYd3Se2WkppzlRoLYS1916fVlFVFrJJgXP DPxxr7wAbZuqN26XntPlBauxpbYSEhv9EMgUp8PtcwUMEIuyosZz49MtveDbQ7iSXa LsSUk2ykxR05tz8Kb9wXJKayGIphxkdhdsPyEWtk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chris Wilson , Daniel Vetter , Maarten Lankhorst , =?UTF-8?q?Christian=20K=C3=B6nig?= , Alex Deucher , Sumit Semwal Subject: [PATCH 4.14 206/293] dma-buf: Discard old fence_excl on retrying get_fences_rcu for realloc Date: Mon, 29 Jul 2019 21:21:37 +0200 Message-Id: <20190729190840.230106531@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190820.321094988@linuxfoundation.org> References: <20190729190820.321094988@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chris Wilson commit f5b07b04e5f090a85d1e96938520f2b2b58e4a8e upstream. If we have to drop the seqcount & rcu lock to perform a krealloc, we have to restart the loop. In doing so, be careful not to lose track of the already acquired exclusive fence. Fixes: fedf54132d24 ("dma-buf: Restart reservation_object_get_fences_rcu() after writes") Signed-off-by: Chris Wilson Cc: Daniel Vetter Cc: Maarten Lankhorst Cc: Christian König Cc: Alex Deucher Cc: Sumit Semwal Cc: stable@vger.kernel.org #v4.10 Reviewed-by: Christian König Link: https://patchwork.freedesktop.org/patch/msgid/20190604125323.21396-1-chris@chris-wilson.co.uk Signed-off-by: Greg Kroah-Hartman --- drivers/dma-buf/reservation.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/dma-buf/reservation.c +++ b/drivers/dma-buf/reservation.c @@ -394,6 +394,10 @@ int reservation_object_get_fences_rcu(st GFP_NOWAIT | __GFP_NOWARN); if (!nshared) { rcu_read_unlock(); + + dma_fence_put(fence_excl); + fence_excl = NULL; + nshared = krealloc(shared, sz, GFP_KERNEL); if (nshared) { shared = nshared;