From patchwork Mon Aug 5 21:08:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 13754056 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 97505C3DA7F for ; Mon, 5 Aug 2024 21:09:46 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sb4xF-0000Cu-BS; Mon, 05 Aug 2024 17:09:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sb4xD-0008UR-HT for qemu-devel@nongnu.org; Mon, 05 Aug 2024 17:09:19 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sb4xB-0008T4-26 for qemu-devel@nongnu.org; Mon, 05 Aug 2024 17:09:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1722892149; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/g0sHsnAjTQQwqSUZTxHOBU5uq4XarRAoERO1KomibQ=; b=JTFOksgqMtxNAzFLqmkE66g70lqoRzCXgg2hkSrHEoe3zZp+eEgT45hKyv1+Q+0MKLJw+9 bTuHdD0aDZTIu23nanQUDWSEw02dQQ8Q05T1DJGjVXgY949gxBmUCeLHOXR6+TRTFBwBwO UljPYIRWcuq5nOYsAmaB7Orbx0Yvfb4= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-53-Ad9bJgZdO5CgvRA1zr2OJg-1; Mon, 05 Aug 2024 17:09:06 -0400 X-MC-Unique: Ad9bJgZdO5CgvRA1zr2OJg-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C508519560B1; Mon, 5 Aug 2024 21:09:05 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.193.224]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 6BE2530001B7; Mon, 5 Aug 2024 21:09:04 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, qemu-devel@nongnu.org Subject: [PULL 02/13] block-copy: Fix missing graph lock Date: Mon, 5 Aug 2024 23:08:40 +0200 Message-ID: <20240805210851.314076-3-kwolf@redhat.com> In-Reply-To: <20240805210851.314076-1-kwolf@redhat.com> References: <20240805210851.314076-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.143, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org The graph lock needs to be held when calling bdrv_co_pdiscard(). Fix block_copy_task_entry() to take it for the call. WITH_GRAPH_RDLOCK_GUARD() was implemented in a weak way because of limitations in clang's Thread Safety Analysis at the time, so that it only asserts that the lock is held (which allows calling functions that require the lock), but we never deal with the unlocking (so even after the scope of the guard, the compiler assumes that the lock is still held). This is why the compiler didn't catch this locking error. Signed-off-by: Kevin Wolf Message-ID: <20240627181245.281403-2-kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block/block-copy.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/block-copy.c b/block/block-copy.c index 7e3b378528..cc618e4561 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -595,7 +595,9 @@ static coroutine_fn int block_copy_task_entry(AioTask *task) if (s->discard_source && ret == 0) { int64_t nbytes = MIN(t->req.offset + t->req.bytes, s->len) - t->req.offset; - bdrv_co_pdiscard(s->source, t->req.offset, nbytes); + WITH_GRAPH_RDLOCK_GUARD() { + bdrv_co_pdiscard(s->source, t->req.offset, nbytes); + } } return ret;