Messages in this thread | | | Subject | Re: [Patch v2] sysfs: add lockdep class support to s_active | From | (Eric W. Biederman) | Date | Fri, 05 Feb 2010 00:57:12 -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. Based on his work and Peter's suggestion, I write this patch, > hopefully we can fix the warning completely. > > This patch put sysfs s_active into two classes, one is for PM, the other > is for the rest, so lockdep will distinguish them. > > 1. http://lkml.org/lkml/2010/1/10/282
What testing has this patch seen?
In particular does this work to actually clear up the pm case?
Eric
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