Messages in this thread Patch in this message | | | Date | Fri, 3 Nov 2006 19:36:59 +0300 | From | Anton Vorontsov <> | Subject | [PATCH] fix ide-cs hang after device removal 2 |
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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) From: Anton Vorontsov <cbou@mail.ru>
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 <alan@lxorguk.ukuu.org.uk> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Anton Vorontsov <cbou@mail.ru> ---
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; } _ | |