On Fri, 18 Nov 2011 08:57:37 -0800 Jesse Brandeburg <[email protected]> wrote:
> CC'd netdev, and e1000-devel > > On Thu, 17 Nov 2011 17:27:00 -0800 > Steven Rostedt <[email protected]> wrote: > > Here you see that we are calling > > cancel_delayed_work_sync(&adapter->watchdog_task); > > > > The problem is that adapter->watchdog_task grabs the mutex &adapter->mutex. > > > > If the work has started and it blocked on that mutex, the > > cancel_delayed_work_sync() will block indefinitely and we have a > > deadlock. > > > > Not sure what's the best way around this. Can we call e1000_down() > > without grabbing the adapter->mutex? > > Thanks for the report, I'll look at it today and see if I can work out > a way to avoid the bonk. this is a proposed patch to fix the issue: if it works for you please let me know and I will submit it officially through our process e1000: fix lockdep splat in shutdown handler From: Jesse Brandeburg <[email protected]> as reported by Steven Rostedt, e1000 has a lockdep splat added during the recent merge window. The issue is that cancel_delayed_work is called while holding our private mutex. There is no reason that I can see to hold the mutex during pci shutdown, it was more just paranoia that I put the mutex_lock around the call to e1000_down. in a quick survey lots of drivers handle locking differently when being called by the pci layer. The assumption here is that we don't need the mutexes' protection in this function because the driver could not be unloaded while in the shutdown handler which is only called at reboot or poweroff. Reported-by: Steven Rostedt <[email protected]> Signed-off-by: Jesse Brandeburg <[email protected]> --- drivers/net/ethernet/intel/e1000/e1000_main.c | 8 +------- 1 files changed, 1 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c index cf480b5..97b46ba 100644 --- a/drivers/net/ethernet/intel/e1000/e1000_main.c +++ b/drivers/net/ethernet/intel/e1000/e1000_main.c @@ -4716,8 +4716,6 @@ static int __e1000_shutdown(struct pci_dev *pdev, bool *enable_wake) netif_device_detach(netdev); - mutex_lock(&adapter->mutex); - if (netif_running(netdev)) { WARN_ON(test_bit(__E1000_RESETTING, &adapter->flags)); e1000_down(adapter); @@ -4725,10 +4723,8 @@ static int __e1000_shutdown(struct pci_dev *pdev, bool *enable_wake) #ifdef CONFIG_PM retval = pci_save_state(pdev); - if (retval) { - mutex_unlock(&adapter->mutex); + if (retval) return retval; - } #endif status = er32(STATUS); @@ -4783,8 +4779,6 @@ static int __e1000_shutdown(struct pci_dev *pdev, bool *enable_wake) if (netif_running(netdev)) e1000_free_irq(adapter); - mutex_unlock(&adapter->mutex); - pci_disable_device(pdev); return 0; ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
