Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753076AbYK3Mlk (ORCPT ); Sun, 30 Nov 2008 07:41:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751384AbYK3Mlc (ORCPT ); Sun, 30 Nov 2008 07:41:32 -0500 Received: from ey-out-2122.google.com ([74.125.78.27]:6929 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751378AbYK3Mlc (ORCPT ); Sun, 30 Nov 2008 07:41:32 -0500 Message-ID: Date: Sun, 30 Nov 2008 13:41:29 +0100 From: "Kay Sievers" To: "Al Viro" Subject: Re: [PATCH] fix pktcdvd breakage from commit e105b8bfc769b0545b6f0f395179d1e43cbee822 Cc: "Linus Torvalds" , gregkh@suse.de, petero2@telia.com, linux-kernel@vger.kernel.org In-Reply-To: <20081130121909.GV28946@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20081130121909.GV28946@ZenIV.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2500 Lines: 56 On Sun, Nov 30, 2008 at 13:19, Al Viro wrote: > device_create() will create a symlink in /sys/dev/char unless > the class has ->dev_kobj cleared; pktcdvd uses it to populate the > /sys/class/pktcdvd/ with per-device subdirectories. While we do > want /sys/class/pktcdvd/pktcdvd[0-7]/dev to contain a device number, > we definitely do not want it to try and crap into /sys/dev/char; if > nothing else, device number is *block* one (and we don't want it > to crap into /sys/dev/block either - there such symlinks will be created > by add_disk() and they will point to /sys/block/pktcdvd[0-7]). > > As it is, attempt to set the damn thing up will end up with > sysfs_add_one() barfing at duplicate entries and /sys/class/pktcdvd/pktcdvd*/*/ > not created at all. The fix is trivial: clear ->dev_kobj in the class to > tell device_add() that no, we do *not* want these symlinks, TYVM... > > FWIW, all traces containing pkt_setup_dev() on kerneloops.org appear > to be from that one. It had been around since 2.6.26; probably -stable > fodder... > > Signed-off-by: Al Viro > --- > diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c > index f20bf35..79981f2 100644 > --- a/drivers/block/pktcdvd.c > +++ b/drivers/block/pktcdvd.c > @@ -417,6 +417,7 @@ static int pkt_sysfs_init(void) > printk(DRIVER_NAME": failed to create class pktcdvd\n"); > return ret; > } > + class_pktcdvd->dev_kobj = NULL; > return 0; > } I posted a fix for that weeks ago. But the pktcdvd maintainer stated, that the char device nodes are not used for anything. So the whole use of dev_t should be removed entirely. They just blindly claim the same char dev_t the block devices use, and conflict with char devices from other subsystems. Patching out the /sys/dev/class links fixes the oops, but the underlying fundamental breakage will still exist. Original mail here states: "Maybe, but that character device would not be used for anything, besides creating sub-directories in /sys/class/pktcdvd. The driver implements a block device, not a character device." http://lkml.org/lkml/2008/10/14/318 No idea why this never got fixed. Thanks, Kay -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/