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 0034EC35FFA for ; Wed, 19 Mar 2025 08:54:08 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tupAk-0003Mo-BF; Wed, 19 Mar 2025 04:53:10 -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 1tupAh-0003Lr-Nc for qemu-devel@nongnu.org; Wed, 19 Mar 2025 04:53:07 -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 1tupAg-0007M1-2A for qemu-devel@nongnu.org; Wed, 19 Mar 2025 04:53:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1742374384; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=C92hBXnysuak+24tdj+yY5c+42bdE0sQG5DkJrTpHAo=; b=gn1hQy2KFQYsGL904TCwcICom8M+kOhojjB3nZAmqMNnWGxc5X7tja9j5deXXNWnt+n+jn L4+4aFzVhIsu74FOLKbeQLSPKxJhBAlGIYGyqn0E4tOzys2m+Zb45ryn/dgcrw2ee/fXED r0bTtxho5dcKtStF7hCmfUq1FIjpPg4= Received: from mx-prod-mc-08.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-147-5rfIloyfMHKNEQOfMXJqEQ-1; Wed, 19 Mar 2025 04:53:00 -0400 X-MC-Unique: 5rfIloyfMHKNEQOfMXJqEQ-1 X-Mimecast-MFC-AGG-ID: 5rfIloyfMHKNEQOfMXJqEQ_1742374380 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D5DA9180882E; Wed, 19 Mar 2025 08:52:59 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.22.74.4]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id DCC091956095; Wed, 19 Mar 2025 08:52:58 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id EE3C421E66C5; Wed, 19 Mar 2025 09:52:54 +0100 (CET) From: Markus Armbruster To: bibo mao Cc: Song Gao , Jiaxun Yang , qemu-devel@nongnu.org, Paolo Bonzini Subject: Re: [PATCH v4 4/4] target/loongarch: Set dest error with error_abort in virt_cpu_irq_init In-Reply-To: <3d9c1bff-c1a5-5e87-e912-7246c2c8f512@loongson.cn> (bibo mao's message of "Wed, 19 Mar 2025 15:58:37 +0800") References: <20250319020847.1511759-1-maobibo@loongson.cn> <20250319020847.1511759-5-maobibo@loongson.cn> <877c4l4km1.fsf@pond.sub.org> <3d9c1bff-c1a5-5e87-e912-7246c2c8f512@loongson.cn> Date: Wed, 19 Mar 2025 09:52:54 +0100 Message-ID: <8734f91jx5.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.332, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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 bibo mao writes: On 2025/3/19 =E4=B8=8B=E5=8D=882:09, Markus Armbruster wrote: >> Bibo Mao writes: >>=20 >>> In function virt_cpu_irq_init(), there is notification with ipi and ext= ioi >>> interrupt controller for cpu creation. Local variable with error type is >>> used, however there is no check with its return value. >>=20 >> Good catch. >>=20 >> When the first call fails, we pass non-null @err to the second call, >> which is wrong. If that one also fails, it'll likely trip >> error_setv()'s assertion. >>=20 >>> Here set dest error object with error_abort, rather than local variable= , so >>> application will abort to run if there is error. >>=20 >> Why is failure impossible there? > In plug hanlder of extioi/ipi, there is only warn_report() if object is=20 > not TYPE_LOONGARCH_CPU, parameter errp is not changed. > > With caller funciton virt_cpu_irq_init(), DEVICE(cs) is object with type= =20 > TYPE_LOONGARCH_CPU always, so failure is impossible here. > >>=20 >> If failure is impossible, the code before the patch is harmlessly wrong. > yes, it is harmlessly wrong. Could use something like target/loongarch: Clean up virt_cpu_irq_init() error handling The Error ** argument must be NULL, &error_abort, &error_fatal, or a pointer to a variable containing NULL. Passing an argument of the latter kind twice without clearing it in between is wrong: if the first call sets an error, it no longer points to NULL for the second call. =20=20=20=20 virt_cpu_irq_init() is wrong that way: it passes &err to hotplug_handler_plug() twice. If both calls failed, this could trip error_setv()'s assertion. Moreover, if just one fails, the Error object leaks. Fortunately, these calls can't actually fail. Messed up in commit 50ebc3fc47f7 (hw/intc/loongarch_ipi: Notify ipi object when cpu is plugged) and commit 087a23a87c57 (hw/intc/loongarch_extioi: Use cpu plug notification). Clean this up by clearing passing &error_abort instead. Signed-off-by: Bibo Mao Note: I replaced the Fixes: tags by a "Messed up ..." paragraph, because there is no bug to fix according to your explanation. With something like that: Acked-by: Markus Armbruster > Regards > Bibo Mao >>=20 >> If failure is possible, the code before the patch has a crash bug, and >> the patch makes it crash harder, i.e. when either call fails instead of >> when both fail. >>=20 >>> Fixes: 50ebc3fc47fe (hw/intc/loongarch_ipi: Notify ipi object when cpu = is plugged) >>> Fixes: 087a23a87c57 (hw/intc/loongarch_extioi: Use cpu plug notificatio= n) >>> Signed-off-by: Bibo Mao