From 0b2c2a71e6f07fb67e6f72817d39910f64d2e258 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 24 May 2017 10:15:32 +0200 Subject: PCI: Replace the racy recursion prevention pci_call_probe() can called recursively when a physcial function is probed and the probing creates virtual functions, which are populated via pci_bus_add_device() which in turn can end up calling pci_call_probe() again. The code has an interesting way to prevent recursing into the workqueue code. That's accomplished by a check whether the current task runs already on the numa node which is associated with the device. While that works to prevent the recursion into the workqueue code, it's racy versus normal execution as there is no guarantee that the node does not vanish after the check. There is another issue with this code. It dereferences cpumask_of_node() unconditionally without checking whether the node is available. Make the detection reliable by: - Mark a probed device as 'is_probed' in pci_call_probe() - Check in pci_call_probe for a virtual function. If it's a virtual function and the associated physical function device is marked 'is_probed' then this is a recursive call, so the call can be invoked in the calling context. - Add a check whether the node is online before dereferencing it. Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Acked-by: Bjorn Helgaas Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: linux-pci@vger.kernel.org Cc: Sebastian Siewior Cc: Steven Rostedt Link: http://lkml.kernel.org/r/20170524081548.771457199@linutronix.de --- include/linux/pci.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/pci.h') diff --git a/include/linux/pci.h b/include/linux/pci.h index 33c2b0b77429..5026f2ae86db 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -371,6 +371,7 @@ struct pci_dev { unsigned int irq_managed:1; unsigned int has_secondary_link:1; unsigned int non_compliant_bars:1; /* broken BARs; ignore them */ + unsigned int is_probed:1; /* device probing in progress */ pci_dev_flags_t dev_flags; atomic_t enable_cnt; /* pci_enable_device has been called */ -- cgit v1.2.3-70-g09d2