From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757684AbcH2PTA (ORCPT ); Mon, 29 Aug 2016 11:19:00 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:47672 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756125AbcH2PS7 (ORCPT ); Mon, 29 Aug 2016 11:18:59 -0400 Date: Mon, 29 Aug 2016 16:18:55 +0100 From: Al Viro To: Takashi Iwai Cc: Ian Kent , autofs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: 4.8-rc4 spews "BUG: sleeping function called from invalid context at fs/dcache.c:757" Message-ID: <20160829151855.GH2356@ZenIV.linux.org.uk> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 29, 2016 at 04:35:46PM +0200, Takashi Iwai wrote: > [] dput+0x46/0x400 ... which should not be called in atomic contexts > [] follow_down_one+0x27/0x60 ... and neither should this > [] autofs4_mount_busy+0x32/0x110 ... nor that (for fsck sake, there's full-blown path_put() in it!) > [] should_expire+0x51/0x3d0 ... so that would better not be called in atomic either (incidentally, it also calls dput() directly) > [] autofs4_expire_indirect+0x190/0x2d0 ... while here it is called under sbi->fs_lock. > I don't remember of a similar stack trace in the past, so if any, it > can be a regression in 4.8 kernel. But I cannot say it in 100%, as > this looks spontaneous, nor I would be able to reproduce it at the > next boot... It's old; the race is narrow, but it's been there for quite a while, by the look of it.