Messages in this thread | | | Date | Sun, 14 Oct 2012 21:24:46 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [STABLE REQUEST] add: e1000: fix lockdep splat in shutdown handler |
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On Thu, 11 Oct 2012, Steven Rostedt wrote: > commit 3a3847e007aae732d64d8fd1374126393e9879a3 > Author: Jesse Brandeburg <jesse.brandeburg@intel.com> > Date: Wed Jan 4 20:23:33 2012 +0000 > > e1000: fix lockdep splat in shutdown handler
as I discussed with Jesse on IRC, there is another possible deadlock lurking in the e1000 code.
static void e1000_reinit_safe(struct e1000_adapter *adapter) { while (test_and_set_bit(__E1000_RESETTING, &adapter->flags)) msleep(1); mutex_lock(&adapter->mutex); e1000_down(adapter);
e1000_down() waits on the various work tasks to shut down, but those work functions might be blocked on the adapter mutex.
I have no idea how I managed to trigger that one, but it's real. The task dump I got out of the machine shows stuff waiting on each other forever.
I can't give you a receipe to reprodruce. Looking at the code this is not very surprising. It takes quite some coincidence of having e1000_reinit_safe() being invoked and the delayed work timer bringing the work on right after e1000_reinit_safe() took the adapter mutex.
Thanks,
tglx
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