Re: [BUG] wireless : cpu stuck for 61s

Bob Copeland
2008-08-05T12:25:14Z

On Tue, Aug 05, 2008 at 09:29:26AM +0800, Dave Young wrote:
> With the patch I cann't reproduce the bug with 27-rc1 now.
>
> > [<c02375a6>] ? debugfs_create_file+0x46/0x210
> > [<c02375a6>] ? debugfs_create_file+0x46/0x210
> > [<c02375a6>] debugfs_create_file+0x46/0x210
> > [<c02377f1>] debugfs_create_dir+0x21/0x30
> > [<f8901f6d>] ieee80211_sta_debugfs_add+0x2d/0x150 [mac80211]
> > [<f88eba89>] sta_info_debugfs_add_work+0x89/0x130 [mac80211]
> > [<f890a170>] ? rate_control_pid_add_sta_debugfs+0x0/0x30 [mac80211]

I wonder if there were two separate problems here. I looked into
this with some detail yesterday and agree with Johannes that the above
trace is on locking the parent directory's i_mutex, but I too couldn't
see any problems with sta_info_debugfs_add_work. Other stuff could also
modify the directory with or without rtnl_lock, but not in a way that
to my untrained eyes would lead to deadlock.

Or is the trace just wrong?

--
Bob Copeland %% www.bobcopeland.com