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 016CE1CAA8D; Mon, 10 Mar 2025 23:58:33 +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=1741651116; cv=none; b=n4Mz7Q7JcdyzxcI5QsI0qkQn7/wtyOAl06rX9Y1auRCyMs2to5/hoTyboKPfHoXPC+1KP2oO2xkZZQ2BCtBxYcEfrY4XbDJCLp3eBhfy8o6soyOibSgDRE43FW3I9JF0Q6TyZGme4pVLPv1kvDcyi0Vcg3Q6EE+0PtrtJ5NCFhk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741651116; c=relaxed/simple; bh=HRL9dvhLGHgZ+t15fYgJdlkg9n7P/vSyCsVNBTwdSM8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bAVv2NsR3jyVnje4oR7i+VCjG+nZHZSuBdEsDrjz4HMbXL8DUmDCb8Srj7hOlkegfbTTvBEbTim9SDwgYv/Xr9WPHzcGExYFP2oPb9e8+uPt6GyGcy6zaMAHEDiwDIuZfEWEMyCpXnkSquvrHHxFrjKxFVeHoGfOrRTUWWHtJn0= 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=ZXxaa+B0; 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="ZXxaa+B0" 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=O6tK3nGR9KVemkXaRkWRrwdgE+3x50H2PRIQcPyhrvo=; b=ZXxaa+B0/9a66QMHGuH2l4nkZ2 M4zkg/q7zAYTmX6PBs1NOhDVV6YH91BM48dIe4VSD6vLIQ4BMiDJgbTRms6c0OvFw1QlTWUIKJLbM xiY4VaLuqMKlllfgRQZDb15WXl8F5xxQ/K9ZboE+Bi+xUJwLS34oO5zB/iyMEq28JuxyJRQ4WpxI2 kF5PL6n8epgUirusUxs8k7l8ZFihWvRomDR6yZ/jS2nPXjkyhLBda2N6/NFc7tUx/cYkt2o4H6pEw XGSotvNcz1AuuKVjtdNYGafNGjTxHRxEtzrPBJAX5b5T83GSMBdrOcuOVP6FoFnQqBUe5qUKhllfm Xto2AsOA==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.1 #2 (Red Hat Linux)) id 1trn0x-00000002rRM-0zDw; Mon, 10 Mar 2025 23:58:31 +0000 Date: Mon, 10 Mar 2025 23:58:31 +0000 From: Al Viro To: Ard Biesheuvel Cc: James Bottomley , syzbot , jk@ozlabs.org, linux-efi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [efi?] [fs?] possible deadlock in efivarfs_actor Message-ID: <20250310235831.GL2023217@ZenIV> References: <67cd0276.050a0220.14db68.006c.GAE@google.com> <8cf7d7efdc069772d69f913b02e5f67feadce18e.camel@HansenPartnership.com> Precedence: bulk X-Mailing-List: linux-efi@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: Sender: Al Viro On Mon, Mar 10, 2025 at 07:21:53PM +0100, Ard Biesheuvel wrote: > The repro log also has > > program crashed: BUG: unable to handle kernel paging request in > efivarfs_pm_notify > > preceding the other log output regarding the locks, so the deadlock > might be a symptom of another problem. This: struct path path = { .mnt = NULL, .dentry = sfi->sb->s_root, }; _What_ .mnt = NULL? That's already a bug. There is no such thing as mountless open file; how would the kernel know not to shut the damn thing down right under you?