From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753269AbWKCPew (ORCPT ); Fri, 3 Nov 2006 10:34:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753270AbWKCPev (ORCPT ); Fri, 3 Nov 2006 10:34:51 -0500 Received: from mx27.mail.ru ([194.67.23.64]:65083 "EHLO mx27.mail.ru") by vger.kernel.org with ESMTP id S1753269AbWKCPeu (ORCPT ); Fri, 3 Nov 2006 10:34:50 -0500 X-Nat-Received: from [10.10.231.1]:2380 [ident-empty] by rt-cwn.z-net.ru with TPROXY id 1162568092.17157 abuse-to abuse@ss-lan.ru Date: Fri, 3 Nov 2006 19:36:59 +0300 From: Anton Vorontsov To: Andrew Morton Cc: James.Bottomley@steeleye.com, alan@lxorguk.ukuu.org.uk, greg@kroah.com, viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org Subject: [PATCH] fix ide-cs hang after device removal 2 Message-ID: <20061103163659.GA16034@localhost> Reply-To: cbou@mail.ru MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="FL5UXtIhxfXey3p5" Content-Disposition: inline User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --FL5UXtIhxfXey3p5 Content-Type: text/plain; charset=koi8-r Content-Disposition: inline Hi! Andrew, can you please replace fix-ide-cs-hang-after-device-removal.patch by attached one? They are exactly same, but -2.patch do not touches SCSI's sd.c. Todd Blumer found that SCSI do get_device() and must put it back, thus my assumption that SCSI also affected was wrong. Thanks, -- Anton (irc: bd2) --FL5UXtIhxfXey3p5 Content-Type: text/plain; charset=koi8-r Content-Disposition: attachment; filename="fix-ide-cs-hang-after-device-removal-2.patch" From: Anton Vorontsov I've caught deadlock inside IDE layer using IDE-CS: after accessing to IDE disk placed in PCMCIA (CF card really), it will never probe again after pulling it from PCMCIA/CF. The kernel is stuck at drivers/ide/ide.c:ide_unregister():604: 602 spin_unlock_irq(&ide_lock); 603 device_unregister(&drive->gendev); 604 wait_for_completion(&drive->gendev_rel_comp); 605 spin_lock_irq(&ide_lock); ide_unregister() assumes that device_unregister() will call ide-probe.c:drive_release_dev(): 1282 static void drive_release_dev (struct device *dev) 1283 { .... [...] 1302 complete(&drive->gendev_rel_comp); 1303 } 1311 static void init_gendisk (ide_hwif_t *hwif) 1312 { .... 1323 drive->gendev.release = drive_release_dev; .... 1333 } But release() function will not called because drive->gendev is still referenced inside genhd layer. No need to get_device(driverfs_dev), because it's already gotten by add_disk(). And no function will call put_device() second time. This is the source of deadlock[1] in IDE layer. [1] deadlock in ide_unregister() at wait_for_completion(&drive->gendev_rel_comp) after device_unregister(&drive->gendev). That happens by reason of ide-probe.c:drive_release_dev() not called because of driverfs_dev (which is drive->gendev) still referenced by add_disk(). Cc: Alan Cox Cc: James Bottomley Cc: Al Viro Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Anton Vorontsov --- fs/partitions/check.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/fs/partitions/check.c b/fs/partitions/check.c index 6fb4b61..8371adf 100644 --- a/fs/partitions/check.c +++ b/fs/partitions/check.c @@ -378,7 +378,7 @@ static char *make_block_name(struct gend static int disk_sysfs_symlinks(struct gendisk *disk) { - struct device *target = get_device(disk->driverfs_dev); + struct device *target = disk->driverfs_dev; int err; char *disk_name = NULL; @@ -414,9 +414,8 @@ err_out_dev_link: sysfs_remove_link(&disk->kobj, "device"); err_out_disk_name: kfree(disk_name); -err_out: - put_device(target); } +err_out: return err; } _ --FL5UXtIhxfXey3p5--