From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 3D4023858036 for ; Thu, 22 Sep 2022 12:19:05 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 3D4023858036 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1663849144; 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=Tp1bpt/vCIPscBFabRJ7EjSR2y3UFNnbZVRkCo0qa6w=; b=PziULacvy7UgxafLDfJQYX5x6UTdjz124AnJWbcUDwQWlIREZHIli/sra9kMrB8hTZK61G omaDFJAXN88gyq2lW5myI/0oxfUI3cvvHNWoBfKLupRrSEjgt17jkTq0c2gcU4dMopx/l2 6Sm7xuL5IClvio8OZry+9icMZ2dRu/o= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-526-lkg4qI4VM_mB3nj1EnfuzA-1; Thu, 22 Sep 2022 08:19:01 -0400 X-MC-Unique: lkg4qI4VM_mB3nj1EnfuzA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 877E787B2A1; Thu, 22 Sep 2022 12:19:01 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.192.103]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0925E2166B26; Thu, 22 Sep 2022 12:19:00 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella Netto Cc: Adhemerval Zanella Netto via Libc-alpha Subject: Re: [committed] hppa: undef __ASSUME_SET_ROBUST_LIST References: <87illg3nao.fsf@oldenburg.str.redhat.com> <8602654c-c619-07b9-bf80-d6cb06030ce1@linaro.org> Date: Thu, 22 Sep 2022 14:18:59 +0200 In-Reply-To: <8602654c-c619-07b9-bf80-d6cb06030ce1@linaro.org> (Adhemerval Zanella Netto's message of "Wed, 21 Sep 2022 10:56:56 -0300") Message-ID: <87h70zmwjw.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-11.0 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,RCVD_IN_DNSWL_LOW,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: * Adhemerval Zanella Netto: > On 21/09/22 09:49, Florian Weimer wrote: >> * Adhemerval Zanella Netto via Libc-alpha: >> >>> On 20/09/22 17:20, John David Anglin wrote: >>>> QEMU does not support support set_robust_list. Thus, we need >>>> to enable detection of set_robust_list system call. >>>> >>>> Signed-off-by: John David Anglin >>>> --- >>>> diff --git a/sysdeps/unix/sysv/linux/hppa/kernel-features.h b/sysdeps/unix/sysv/linux/hppa/kernel-features.h >>>> index 0cd21ef0fa..079612e4aa 100644 >>>> --- a/sysdeps/unix/sysv/linux/hppa/kernel-features.h >>>> +++ b/sysdeps/unix/sysv/linux/hppa/kernel-features.h >>>> @@ -30,3 +30,6 @@ >>>> >>>> #undef __ASSUME_CLONE_DEFAULT >>>> #define __ASSUME_CLONE_BACKWARDS 1 >>>> + >>>> +/* QEMU does not support set_robust_list. */ >>>> +#undef __ASSUME_SET_ROBUST_LIST >>>> >>> >>> Does it happen only for hppa? If is a generic missing feature maybe we should >>> undef __ASSUME_SET_ROBUST_LIST for all architectures. >> >> I think it's just a 32-bit/64-bit mismatch issue. You can't create >> 32-bit robust futexes from a 64-bit process because the pointer size in >> the robust list differs. For non-process-shared mutexes, qemu-user >> should be able to emulate these futexes in userspace. It already has to >> intercept thread exit, and it can walk the mutex list at that time. >> >> I don't think it makes sense to pessimize bare-metal uses simply because >> there's a qemu-user limitation. > > Should we revert the hppa fix then? Probably? It seems to be an emulation-only problem. Thanks, Florian