Messages in this thread | | | Date | Fri, 29 Jan 2010 16:38:23 +0800 | From | Cong Wang <> | Subject | Re: [Patch 0/2] sysfs: fix s_active lockdep warning |
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Eric W. Biederman wrote: > Amerigo Wang <amwang@redhat.com> writes: > >> Recently we met a lockdep warning from sysfs during s2ram or cpu hotplug. >> As reported by several people, it is something like: >> >> [ 6967.926563] ACPI: Preparing to enter system sleep state S3 >> [ 6967.956156] Disabling non-boot CPUs ... >> [ 6967.970401] >> [ 6967.970408] ============================================= >> [ 6967.970419] [ INFO: possible recursive locking detected ] >> [ 6967.970431] 2.6.33-rc2-git6 #27 >> [ 6967.970439] --------------------------------------------- >> [ 6967.970450] pm-suspend/22147 is trying to acquire lock: >> [ 6967.970460] (s_active){++++.+}, at: [<c10d2941>] >> sysfs_hash_and_remove+0x3d/0x4f >> [ 6967.970493] >> [ 6967.970497] but task is already holding lock: >> [ 6967.970506] (s_active){++++.+}, at: [<c10d4110>] >> sysfs_get_active_two+0x16/0x36 >> [...] >> >> Eric already provides a patch for this[1], but it still can't fix the >> problem. I add the missing part of Eric's patch and send these two patches >> together, hopefully we can fix the warning completely. >> >> 1. http://lkml.org/lkml/2010/1/10/282 >> >> >> Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> >> Reported-by: Larry Finger <Larry.Finger@lwfinger.net> >> Reported-by: Miles Lane <miles.lane@gmail.com> >> Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> >> Signed-off-by: WANG Cong <amwang@redhat.com> >> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> >> Cc: Tejun Heo <tj@kernel.org> >> Cc: Greg Kroah-Hartman <gregkh@suse.de> > > Thanks for following up on this. > > I suspect we may want to create a separate class for each sysfs file > instead of playing whack-a-mole and creating a subclass each time we > have problems. > > I don't see why the rules for one sysfs file should be the same as for > any other sysfs file. >
I am confused, we don't know who created sysfs files unless we separate them by subclasses, the way of your patch is very straight ward.
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