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 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 35DD9CCD184 for ; Thu, 9 Oct 2025 16:07:57 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1v6tAC-0000xa-I7; Thu, 09 Oct 2025 12:06:44 -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 1v6t9z-0000wO-AS for qemu-devel@nongnu.org; Thu, 09 Oct 2025 12:06:31 -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 1v6t9l-0007PL-4g for qemu-devel@nongnu.org; Thu, 09 Oct 2025 12:06:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1760025971; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=b4JEmYP1t5XShIQYpC0PcoBZPFy0qgi7og0Jk/yy3zE=; b=hnq1pfB/hO534uuEMjdkLKs5JXXgSvBKSYrw9C8d2tyGKEbmt9NYDCa6arTkZTIaKwl/qO AogVC+KIKXaTG9s63LTSX+DHGdBK7xo/ODU9KGJccsNCNGp2bPIIg8sbEL/W+S5u5vNlGi kZTrrxbSNoJxo+7O+dw0SEbPaEzvYY8= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-433-9L1I4UtsNV-qJF7bQKYpCQ-1; Thu, 09 Oct 2025 12:06:09 -0400 X-MC-Unique: 9L1I4UtsNV-qJF7bQKYpCQ-1 X-Mimecast-MFC-AGG-ID: 9L1I4UtsNV-qJF7bQKYpCQ_1760025968 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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8970418004D8; Thu, 9 Oct 2025 16:06:07 +0000 (UTC) Received: from redhat.com (unknown [10.44.32.99]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 518F630001B7; Thu, 9 Oct 2025 16:06:02 +0000 (UTC) Date: Thu, 9 Oct 2025 18:06:00 +0200 From: Kevin Wolf To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org, Aarushi Mehta , Fam Zheng , Stefano Garzarella , Hanna Czenczek , eblake@redhat.com, qemu-block@nongnu.org, hibriansong@gmail.com, Stefan Weil , Paolo Bonzini Subject: Re: [PATCH v4 06/12] aio: free AioContext when aio_context_new() fails Message-ID: References: <20250910175703.374499-1-stefanha@redhat.com> <20250910175703.374499-7-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250910175703.374499-7-stefanha@redhat.com> 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: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.438, 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, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_PASS=-0.001, T_SPF_HELO_TEMPERROR=0.01 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 Am 10.09.2025 um 19:56 hat Stefan Hajnoczi geschrieben: > g_source_destroy() only removes the GSource from the GMainContext it's > attached to, if any. It does not free it. > > Use g_source_unref() instead so that the AioContext (which embeds a > GSource) is freed. There is no need to call g_source_destroy() in > aio_context_new() because the GSource isn't attached to a GMainContext > yet. > > aio_ctx_finalize() expects everything to be set up already, so introduce > the new ctx->initialized boolean and do nothing when called with > !initialized. This also requires moving aio_context_setup() down after > event_notifier_init() since aio_ctx_finalize() won't release any > resources that aio_context_setup() acquired. > > Signed-off-by: Stefan Hajnoczi > Reviewed-by: Eric Blake > --- > v2: > - Fix spacing in aio_ctx_finalize() argument list [Eric] > --- > include/block/aio.h | 3 +++ > util/async.c | 14 +++++++++++--- > 2 files changed, 14 insertions(+), 3 deletions(-) > > diff --git a/include/block/aio.h b/include/block/aio.h > index 1657740a0e..2760f308f5 100644 > --- a/include/block/aio.h > +++ b/include/block/aio.h > @@ -291,6 +291,9 @@ struct AioContext { > gpointer epollfd_tag; > > const FDMonOps *fdmon_ops; > + > + /* Was aio_context_new() successful? */ > + bool initialized; > }; > > /** > diff --git a/util/async.c b/util/async.c > index a39410d675..34aaab4e9e 100644 > --- a/util/async.c > +++ b/util/async.c > @@ -363,12 +363,16 @@ aio_ctx_dispatch(GSource *source, > } > > static void > -aio_ctx_finalize(GSource *source) > +aio_ctx_finalize(GSource *source) > { > AioContext *ctx = (AioContext *) source; > QEMUBH *bh; > unsigned flags; > > + if (!ctx->initialized) { > + return; > + } You had to move aio_context_setup() down in aio_context_new() to make sure that this doesn't leak things. How will we make sure that nobody adds another error path after allocating something after g_source_new()? g_source_new() doesn't seem to guarantee that AioContext starts zeroed, which is annoying if we wanted to just make aio_ctx_finalize() safe to be called from before the first error path. > thread_pool_free_aio(ctx->thread_pool); > > #ifdef CONFIG_LINUX_AIO > @@ -579,13 +583,15 @@ AioContext *aio_context_new(Error **errp) > ctx = (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext)); > QSLIST_INIT(&ctx->bh_list); > QSIMPLEQ_INIT(&ctx->bh_slice_list); > - aio_context_setup(ctx); > > ret = event_notifier_init(&ctx->notifier, false); > if (ret < 0) { > error_setg_errno(errp, -ret, "Failed to initialize event notifier"); > goto fail; > } > > + > + aio_context_setup(ctx); Can we at least add a comment here saying that there must be no error after this aio_context_setup() call any more because we would then leak things? > g_source_set_can_recurse(&ctx->source, true); > qemu_lockcnt_init(&ctx->list_lock); > > @@ -619,9 +625,11 @@ AioContext *aio_context_new(Error **errp) > > register_aiocontext(ctx); > > + ctx->initialized = true; > + > return ctx; > fail: > - g_source_destroy(&ctx->source); > + g_source_unref(&ctx->source); > return NULL; > } Kevin