Hi,
On Thursday 26 June 2008, Pavel Machek wrote:
> Hi!
>
> > > Hmm, hitting sysrq-w produces no blocked task until I eject pcmcia
> > > card. Backtrace there is:
> > >
> > > Greg, I believe some traces lead to sysfs, can you help here?
> >
> > ide_unregister() does not complete :-(.
> >
> > device_unregister(&hwif->gendev);
> > + printk("ide_unregister: waiting for rel_comp\n");
> > wait_for_completion(&hwif->gendev_rel_comp);
> >
> > ...that wait_for_completion never returns.
[...]
Thanks for narrowing it down to wait_for_completion() call,
it was an useful hint.
From: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
Subject: [PATCH] ide: fix hwif->gendev refcounting
class->dev_release is called by device_release() iff dev->release
is not present so ide_port_class_release() is never called and the
last hwif->gendev reference is not dropped.
Fix it by removing ide_port_class_release() and get_device() call
from ide_register_port() (device_create_drvdata() takes a hwif->gendev
reference anyway).
This patch fixes hang on wait_for_completion(&hwif->gendev_rel_comp)
in ide_unregister() reported by Pavel Machek.
Cc: Pavel Machek <pavel@xxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
---
drivers/ide/ide-probe.c | 2 --
drivers/ide/ide.c | 8 --------
2 files changed, 10 deletions(-)
Index: b/drivers/ide/ide-probe.c
===================================================================
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -646,8 +646,6 @@ static int ide_register_port(ide_hwif_t
goto out;
}
- get_device(&hwif->gendev);
-
hwif->portdev = device_create_drvdata(ide_port_class, &hwif->gendev,
MKDEV(0, 0), hwif, hwif->name);
if (IS_ERR(hwif->portdev)) {
Index: b/drivers/ide/ide.c
===================================================================
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -1094,13 +1094,6 @@ struct bus_type ide_bus_type = {
EXPORT_SYMBOL_GPL(ide_bus_type);
-static void ide_port_class_release(struct device *portdev)
-{
- ide_hwif_t *hwif = dev_get_drvdata(portdev);
-
- put_device(&hwif->gendev);
-}
-
int ide_vlb_clk;
EXPORT_SYMBOL_GPL(ide_vlb_clk);
@@ -1305,7 +1298,6 @@ static int __init ide_init(void)
ret = PTR_ERR(ide_port_class);
goto out_port_class;
}
- ide_port_class->dev_release = ide_port_class_release;
init_ide_data();
--
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