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 580DECA1013 for ; Thu, 18 Sep 2025 14:23:49 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uzFXW-00081U-SY; Thu, 18 Sep 2025 10:23:15 -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 1uzFXR-00080Y-Op for qemu-devel@nongnu.org; Thu, 18 Sep 2025 10:23:10 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uzFXP-0001lu-Tl for qemu-devel@nongnu.org; Thu, 18 Sep 2025 10:23:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1758205384; 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=5Hc4qkmEJBJ0xlhXj7zXQTeDKkFeD/p8WCnI5AR92hw=; b=Wx6WUHVi89Sec3E+YCaCK8gmaiMh6uQzqkGbDm+GTl0J3ZEWjos8Vs2pQWnpqpgECo3EvY pCBkMXaIlnDF8I1HLGKrvacFPFs0C0U2jgXlHS6+DQ/FI001rSJ+MbTa7WDvGtr9cOxV5Q IsEEHa/C3jdKa+m8bh3UQgj/ebWo7vw= 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-480-oDtTs9FEOfaYJ5rPODFfWQ-1; Thu, 18 Sep 2025 10:23:02 -0400 X-MC-Unique: oDtTs9FEOfaYJ5rPODFfWQ-1 X-Mimecast-MFC-AGG-ID: oDtTs9FEOfaYJ5rPODFfWQ_1758205381 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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 C72BD1800292; Thu, 18 Sep 2025 14:23:00 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.9]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id F224318003FC; Thu, 18 Sep 2025 14:22:59 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 8739C21E6A27; Thu, 18 Sep 2025 16:22:57 +0200 (CEST) From: Markus Armbruster To: Akihiko Odaki Cc: qemu-devel@nongnu.org, marcandre.lureau@redhat.com, berrange@redhat.com, Richard Henderson Subject: Re: [PATCH v2 02/12] tcg: Fix error reporting on mprotect() failure in tcg_region_init() In-Reply-To: <9bc5b8b1-e68a-4e39-8cbf-4205707f8317@rsg.ci.i.u-tokyo.ac.jp> (Akihiko Odaki's message of "Thu, 18 Sep 2025 21:23:31 +0900") References: <20250917115207.1730186-1-armbru@redhat.com> <20250917115207.1730186-3-armbru@redhat.com> <9bc5b8b1-e68a-4e39-8cbf-4205707f8317@rsg.ci.i.u-tokyo.ac.jp> Date: Thu, 18 Sep 2025 16:22:57 +0200 Message-ID: <87a52ralha.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 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.005, 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_PASS=-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 Akihiko Odaki writes: > On 2025/09/17 20:51, Markus Armbruster wrote: >> tcg_region_init() calls one of qemu_mprotect_rwx(), >> qemu_mprotect_rw(), and mprotect(), then reports failure with >> error_setg_errno(&error_fatal, errno, ...). >> The use of &error_fatal is undesirable. qapi/error.h advises: >> * Please don't error_setg(&error_fatal, ...), use error_report() and >> * exit(), because that's more obvious. >> The use of errno is wrong. qemu_mprotect_rwx() and qemu_mprotect_rw() >> wrap around qemu_mprotect__osdep(). qemu_mprotect__osdep() calls >> mprotect() on POSIX, VirtualProtect() on Windows, and reports failure >> with error_report(). VirtualProtect() doesn't set errno. mprotect() >> does, but error_report() may clobber it. >> Fix tcg_region_init() to report errors only when it calls mprotect(), >> and rely on qemu_mprotect_rwx()'s and qemu_mprotect_rw()'s error >> reporting otherwise. Use error_report(), not error_setg(). >> Fixes: 22c6a9938f75 (tcg: Merge buffer protection and guard page protect= ion) >> Fixes: 6bc144237a85 (tcg: Use Error with alloc_code_gen_buffer) >> Cc: Richard Henderson >> Signed-off-by: Markus Armbruster >> Reviewed-by: Daniel P. Berrang=C3=A9 >> --- >> tcg/region.c | 8 ++++++-- >> 1 file changed, 6 insertions(+), 2 deletions(-) >> diff --git a/tcg/region.c b/tcg/region.c >> index 7ea0b37a84..74e3b4b774 100644 >> --- a/tcg/region.c >> +++ b/tcg/region.c >> @@ -832,13 +832,17 @@ void tcg_region_init(size_t tb_size, int splitwx, = unsigned max_threads) >> } else { >> #ifdef CONFIG_POSIX >> rc =3D mprotect(start, end - start, need_prot); >> + if (rc) { >> + error_report("mprotect of jit buffer: %s", >> + strerror(errno)); >> + } >> + > > Nitpick: this blank line at the end of #ifdef looks strange to me. Accident, will drop it. Thanks! >> #else >> g_assert_not_reached(); >> #endif >> } >> if (rc) { >> - error_setg_errno(&error_fatal, errno, >> - "mprotect of jit buffer"); >> + exit(1); >> } >> } >> if (have_prot !=3D 0) {