From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) (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 BECD31EDA09 for ; Wed, 27 Aug 2025 11:53:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=18.9.28.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756295584; cv=none; b=WJFl7ZyNZsKv04iOoRxwjDqjzDTB06Bhr6s3kCv/w9n3Cycv1FItlC0etrI/e3xW6nMWHyexRH1moj2n3BBNH5NInv/N7tCmsS6Ac/h6E6t+NzerS09rdutCvng0bVd9KxS/HB8Lhq1F8RVevOHuuWc2lR11tp+fbBpGoZ1/QfM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756295584; c=relaxed/simple; bh=Q1wvyfNtpBZ25n7ToqHfhAYceHnQbyTxTlk3YBzAMWM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HUvRokJ0ssZJ7AUaHpxtSRhzKPtcw/Qnb8j7Zop4idHV+o69ojLIssutv3x+si0hbH/cxQARRgUQqb9Ck9gim2tsFFf7JY8m76G+Ahy5iNnIJLaJkj0BOrE385ByN+49xb/flLqq5NyLDMvkD8pa8U9fRwF6sF+RZefJMyrIUr0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mit.edu; spf=pass smtp.mailfrom=mit.edu; dkim=pass (2048-bit key) header.d=mit.edu header.i=@mit.edu header.b=Iy3ioPuq; arc=none smtp.client-ip=18.9.28.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mit.edu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mit.edu Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mit.edu header.i=@mit.edu header.b="Iy3ioPuq" Received: from trampoline.thunk.org (pool-173-48-119-253.bstnma.fios.verizon.net [173.48.119.253]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 57RBqmmf013246 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 27 Aug 2025 07:52:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mit.edu; s=outgoing; t=1756295570; bh=ctUarcq+LCGpo/C7phydeZnd1chontiYFeJ2Bv6TMt0=; h=Date:From:Subject:Message-ID:MIME-Version:Content-Type; b=Iy3ioPuqeJietM2uBdZM13d4LE18QIODtxMiyMI3+utXrLLrFtQghuBzmwdB7y/w7 znSTWNd+VGlMIzloXNUVw1bcB1WuEtsx7N43/k/g7Zcz9wGQPN08XJTDa0b3AgRlky /3L99jGM/kGp9PgboJ9GNUPWkvB395NQtKuuu84U5AEdttrnIGO1FWmuG956dtpxwX PBxSWBJYkS4MrdFPWn34hM/k1CGDeC7XbZ3de2wM5VfT3yOsyujvQUDo/6ARCOCHUi aCcgQauhIqDpiUpIlwzHz6XqtqNphgLEVDkkFjqiibhakEgyQRiZn9PrKICDjWvqBA WbP8ulIcJdzqQ== Received: by trampoline.thunk.org (Postfix, from userid 15806) id D382C2E00D6; Wed, 27 Aug 2025 07:52:47 -0400 (EDT) Date: Wed, 27 Aug 2025 07:52:47 -0400 From: "Theodore Ts'o" To: Alexander Monakov Cc: Al Viro , linux-fsdevel@vger.kernel.org, Christian Brauner , Jan Kara , linux-kernel@vger.kernel.org Subject: Re: ETXTBSY window in __fput Message-ID: <20250827115247.GD1603531@mit.edu> References: <6e60aa72-94ef-9de2-a54c-ffd91fcc4711@ispras.ru> <20250826220033.GW39973@ZenIV> <0a372029-9a31-54c3-4d8a-8a9597361955@ispras.ru> 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=us-ascii Content-Disposition: inline In-Reply-To: <0a372029-9a31-54c3-4d8a-8a9597361955@ispras.ru> On Wed, Aug 27, 2025 at 10:22:14AM +0300, Alexander Monakov wrote: > > On Tue, 26 Aug 2025, Al Viro wrote: > > > Egads... Let me get it straight - you have a bunch of threads sharing descriptor > > tables and some of them are forking (or cloning without shared descriptor tables) > > while that is going on? > > I suppose if they could start a new process in a more straightforward manner, > they would. But you cannot start a new process without fork. Anyway, I'm but > a messenger here: the problem has been hit by various people in the Go community > (and by Go team itself, at least twice). Here I'm asking about a potential > shortcoming in __fput that exacerbates the problem. I'm assuming that the problem is showing up in real life when users run a go problem using "go run" where the golang compiler freshly writes the executable, and then fork/exec's the binary. And using multiple threads sharing descriptor tables was just to make a reliable reproducer? - Ted