Messages in this thread | | | Subject | Re: [Patch 0/2] sysfs: fix s_active lockdep warning | From | (Eric W. Biederman) | Date | Thu, 28 Jan 2010 23:21:46 -0800 |
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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.
Eric
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