Messages in this thread |  | | | From | "Rafael J. Wysocki" <> | | Subject | Re: [linux-pm] [GIT PULL] One more power management fix for 2.6.37 | | Date | Thu, 4 Nov 2010 06:04:05 +0100 |
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On Wednesday, November 03, 2010, Dominik Brodowski wrote: > > There's apparently an ordering problem with dpm_list_mtx and > > socket->skt_mutex. Lockdep details appended. > > > > Dominik, Rafael? What's the proper locking order here, and > > how do we fix this? > > Thanks for noting this; let's see: > > - We add a PCMCIA device holding skt_mutex, therefore we have the ordering > (1) skt_mutex -> (2) dpm_list_mtx > > - If we're suspending, dpm_list_mtx is held, but we need to acquire > skt_mutex as we modify some data being protected by skt_mutex > (1) dpm_list_mtx -> (2) skt_mutex > > Rafael, any idea on how to solve this? How do other subsystems handle such > an issue? Do they call device_add() with no locks held at all?
They usually do from what I can tell.
Also only a few of them implement the ->suspend_noirq() callback, which is the one executed under dpm_list_mtx.
What exactly is protected by skt_mutex ?
Rafael
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