From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from submarine.notk.org (submarine.notk.org [62.210.214.84]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5AE722989BC; Tue, 21 Oct 2025 22:12:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.210.214.84 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761084751; cv=none; b=jRYLGt61yeHjQPfJuTqQWIw2WwdkXxrUJY494wwu/t3p+jgj26hOPks9fmQH+t5Hzt6XzUjo2kJqjst+5N6Tb2n9O1J1Gb8yP1aIyHaqtdflcDGFJJYIPXhvALxCCllgWBgPcDbOJZOgdpVXehyQzjQ39mMXfnykW7YQY/EBSjk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761084751; c=relaxed/simple; bh=ofUIlUcJf+qSxbCYFOj4Dmv8C/Q/gYj+rCTIU17Szqs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DwTx0+dt8MgglW7D0oIeKqnBM+gYBI/5wC2cGWfdfw5gSDSZf2EJA6ioKng1h1BYpS+NPPqtD/9eAFbygTDnLZ8BRXWXBachonE52NVg+PgJEnKJfdzv4wtL1SptF/0wq6AKzRp5kiqGlQ318zORo7KMLF12Cl1MsX4lzeUyVKI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org; spf=pass smtp.mailfrom=codewreck.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b=kX4lhc38; arc=none smtp.client-ip=62.210.214.84 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codewreck.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b="kX4lhc38" Received: from gaia.codewreck.org (localhost [127.0.0.1]) by submarine.notk.org (Postfix) with ESMTPS id B02D014C2D3; Wed, 22 Oct 2025 00:12:18 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1761084741; 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=DvgjUM9pwk9ojxcDr4HMoG2nE5PWiwPcbp29vqBU1MQ=; b=kX4lhc38IASBnGAnsO2gRsnvwMooM10C4XUxJwu1iiBoQ0Yt6dRbGxRdV59OGZmDIh7SJ1 CCCbN+U8fQMKAdz0ruJhqkEutoTsmcoVqmtyro9Brk6JK4EJs8QAJVVAHZfh2o31AjmxGK IcJi68ksWWiz9jNTtOVPbCmUFfJq7t+Rlh8IbUJILZ129kf9BIcftNqZQiPk6ylgFWHp5a Fe1NArMgPxT/x4V4M5Cq8WqVdPAWs4yARjmreAuatu7fowYr69lhmChIsDTQlGujjYF3rK Ed02cDwGfd9zIzELtdIkr8TmufRWTQ0LuNmntysnVeYTFgIaDGrD5QSykKSCSw== Received: from localhost (gaia.codewreck.org [local]) by gaia.codewreck.org (OpenSMTPD) with ESMTPA id f75e589d; Tue, 21 Oct 2025 22:12:17 +0000 (UTC) Date: Wed, 22 Oct 2025 07:12:02 +0900 From: Dominique Martinet To: Alexei Starovoitov Cc: Song Liu , Linux-Fsdevel , Christian Brauner , Tingmao Wang , v9fs@lists.linux.dev, Eric Van Hensbergen , Latchesar Ionkov , Christian Schoenebeck , =?utf-8?Q?Micka=C3=ABl_Sala=C3=BCn?= , bpf Subject: Re: 9P change breaks bpftrace running in qemu+9p? Message-ID: References: <086bb120-22eb-43ff-a486-14e8eeb7dd80@maowtm.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Alexei Starovoitov wrote on Tue, Oct 21, 2025 at 09:56:10AM -0700: > > I am not sure what is the "right" behavior in this case. But this is > > clearly a change of behavior. That's definitely wrong, the resulting file was truncated. Thanks for the repro! I've sent a fix here: https://lkml.kernel.org/r/20251022-mmap-regression-v1-1-980365ee524e@codewreck.org Would be great if you could confirm it fixes your problems, and I'll get it sent to Linus > Andrii reported the issue as well: > https://lore.kernel.org/bpf/CAEf4BzZbCE4tLoDZyUf_aASpgAGFj75QMfSXX4a4dLYixnOiLg@mail.gmail.com/ > > selftests/bpf was relying on the above behavior too > which we adjusted already, but > this looks to be a regression either in 9p or in vfs. Looks like a 9p bug, sorry :( -- Dominique Martinet | Asmadeus