From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-out.m-online.net (mail-out.m-online.net [212.18.0.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EEEB07080B for ; Mon, 9 Dec 2024 18:40:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.18.0.9 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733769660; cv=none; b=bBSDcvQecMiviBl6s0r24x4zqMPcgew5RbIarUF0TzFFxH1m0UK0wUYZIadtG2cyR4MLFoKBj/O2Mc0CStP7OIezUeCwkFfhmRe5Bl9d3DmwZWaJDmj/BB4oPMY33C3aeQ7oBCIXZjjTefZkvkKgn7Mm3F1sk7AoqCje9/NGXnI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733769660; c=relaxed/simple; bh=YyPjvKuJEpM4CNPJs9OhLN+5bRvih8fimdR0plWhrU4=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=TO1X5CGFRYJ5FJB5zHMNnbqB+l3FUmEgEXcegIX0jp4BqviVpu+N1YEPB8dmNY4EJYdnPidxfdcXe6k7/D/u5zvSKlC2TJ3x83DLcKXaH/qXVSsRy1nLe74prygQzzRnc4TLxEJJ01AaV6LmiH2zHuoV/7jSlOV31/7ZR+8X++g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=linux-m68k.org; spf=pass smtp.mailfrom=nefkom.net; arc=none smtp.client-ip=212.18.0.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=linux-m68k.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=nefkom.net Received: from frontend01.mail.m-online.net (unknown [192.168.8.182]) by mail-out.m-online.net (Postfix) with ESMTP id 4Y6Vpr5wGwz1qsPx; Mon, 9 Dec 2024 19:32:52 +0100 (CET) Received: from localhost (dynscan1.mnet-online.de [192.168.6.68]) by mail.m-online.net (Postfix) with ESMTP id 4Y6Vpr58zWz1qqlS; Mon, 9 Dec 2024 19:32:52 +0100 (CET) X-Virus-Scanned: amavis at mnet-online.de Received: from mail.mnet-online.de ([192.168.8.182]) by localhost (dynscan1.mail.m-online.net [192.168.6.68]) (amavis, port 10024) with ESMTP id DAGK58Tns2FM; Mon, 9 Dec 2024 19:32:52 +0100 (CET) X-Auth-Info: oBX17wFr/StoNeFHnknxTLQepuuwk97VrTe1nqtIBhIrx1Gs+J9KHbF0bmaMNbYG Received: from igel.home (aftr-82-135-83-150.dynamic.mnet-online.de [82.135.83.150]) (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 mail.mnet-online.de (Postfix) with ESMTPSA; Mon, 9 Dec 2024 19:32:51 +0100 (CET) Received: by igel.home (Postfix, from userid 1000) id A8E7F2C1B0F; Mon, 9 Dec 2024 19:32:51 +0100 (CET) From: Andreas Schwab To: Linus Torvalds Cc: Josh Poimboeuf , LKML , x86@kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] futex: improve user space accesses In-Reply-To: (Linus Torvalds's message of "Sun, 8 Dec 2024 16:32:33 -0800") References: <20241122193305.7316-1-torvalds@linux-foundation.org> <87bjxl6b0i.fsf@igel.home> X-Yow: Is this an out-take from the ``BRADY BUNCH''? Date: Mon, 09 Dec 2024 19:32:51 +0100 Message-ID: <87bjxkzoz0.fsf@igel.home> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Dez 08 2024, Linus Torvalds wrote: > IOW, does this one-liner fix it for you? > > --- a/kernel/futex/futex.h > +++ b/kernel/futex/futex.h > @@ -265,7 +265,7 @@ > else if (!user_read_access_begin(from, sizeof(*from))) > return -EFAULT; > unsafe_get_user(val, from, Efault); > - user_access_end(); > + user_read_access_end(); > *dest = val; > return 0; > Efault: Thanks, I can confirm that this fixed the crash (changing both arms as pointed out by Christophe). -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."