Messages in this thread |  | | Date | Tue, 9 Feb 2010 17:21:48 -0800 (PST) | From | David Rientjes <> | Subject | Re: [PATCH] sysfs: differentiate between locking links and non-links |
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On Wed, 10 Feb 2010, Neil Brown wrote:
> commit 2e502cfe444b68f6ef6b8b2abe83b6112564095b > Author: NeilBrown <neilb@suse.de> > Date: Wed Feb 10 09:43:45 2010 +1100 > > sysfs: differentiate between locking links and non-links for sysfs > > symlinks and non-symlink is sysfs are very different. > A symlink can never be locked (active) while an attribute > modification routine is running. So removing symlink from an > attribute 'store' routine should be permitted without any lockdep > warnings. > > So split the lockdep context for 's_active' in two, one for symlinks > and other for everything else. >
What happens for hard links such as writing to /sys/devices/block/xxx/queue/scheduler to change an I/O scheduler which requires sd->dep_map and sd->parent->dep_map in sysfs_get_active_two() to pin both? The call to kobject_del() invokes the destruction that also requires sd->dep_map in sysfs_deactivate() because of the s_active lockdep annotation.
This is the scenario that is presented in http://bugzilla.kernel.org/show_bug.cgi?id=15202.
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