From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (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 5007017A2F6 for ; Wed, 3 Sep 2025 05:08:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756876133; cv=none; b=A3hK6Obds2+xoHDJCRev9eCySOo51TUXbpqCjp0i4ciFyO89nazAvYe8M7dhPLDRZ11zBDYwWK4DJE0E8caUj0so/IXItbceb+eoZ2SZuKobBkJ/ftPVHZvZoc0yvmgUs26jVirCdtO8FEvsOPcx+IoryJjJmZNsPtee751pMzw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756876133; c=relaxed/simple; bh=1qp0bOezAKjNtPWINkNe4ZyV69sSzz6K8WxZziNDoek=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=D/s3r33XGJ94VCmwGotDZ3PPd2ERnCY1QR8FpHlfoxle9hggdy1aZXKCcW6S2wF4NF/j3BhI/FgT1AMvK9Wf9RMTGTfNymRl8oKyb1SIbgKU0X0LWeHeaUJWRiCYtu5k2gbo/PjLpaF3zCwS8hUHmGO7F0nXq9g1hryEb5UzxWA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=S2e8n3Kh; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="S2e8n3Kh" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Tkxn4p+DPhUheMjz+EEdn3I5rv/lQOuT88ClNbQ+QfM=; b=S2e8n3KhdU++iZXisiesQL+WsS 0aGmROrOMia45q24RjiKKLSmrvyjxn6puwYuIth5XYHhweQgv6neWj1Ocak0mr/u+qxL85z1FotXO wsF/Uk39VyM38ARMXj8WTxX518iEP1RQikdTeokIG1pSS8veqP9V8erSiEMJm4Ko/Od7iULG3oos3 RvuQp2I19AuyV3bcqdUwUZSU3KJ/zPkOdET548QIoKNexZtQ4uURHJT9KR9JWdTWRFi/DZ8HgKw2e JZjjiuw/IJxaDnDu5rj2jUkN+QWfDa0CE/nUeJxNCnROGzazNpyMUbiOoDYgL6kJAUheBCj8Djcjx QFhKGjHg==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1utfjm-0000000B2Jk-0haq; Wed, 03 Sep 2025 05:08:50 +0000 Date: Wed, 3 Sep 2025 06:08:50 +0100 From: Al Viro To: linux-fsdevel@vger.kernel.org Cc: Linus Torvalds , Christian Brauner , Jan Kara Subject: Re: [PATCHES v3][RFC][CFT] mount-related stuff Message-ID: <20250903050850.GI39973@ZenIV> References: <20250825044046.GI39973@ZenIV> <20250828230706.GA3340273@ZenIV> <20250903045432.GH39973@ZenIV> 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: <20250903045432.GH39973@ZenIV> Sender: Al Viro On Wed, Sep 03, 2025 at 05:54:32AM +0100, Al Viro wrote: > Branch force-pushed into > git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git #work.mount > (also visible as #v3.mount, #v[12].mount being the previous versions) > Individual patches in followups. > > If nobody objects, this goes into #for-next. PS: survives LTP, xfstests and mount-related selftests. FWIW, I've spent the weekend trying to figure out what's going on with generic/475. Turns out that it was not a regression - it goes back at least to 6.12 and it's triggered by PREEMPT vs. PREEMPT_VOLUNTARY in config. The former gives several kinds of failures, with total frequency about 8%; the latter apparently works - if any similar failures happen, the frequency is at least an order of magnitude lower. One useful thing I've got out of that is a bunch of helpers for doing bisect for configs - semi-manual decomposing the difference between two configs into a series of small changes, allowing to do bisection on that. Unfortunately, the change it has converged to (and repeating it alone on the original config reproduces the effect) is not particulary useful - some race gets triggered by a config change that affects timings all over the place ;-/