Messages in this thread | | | Date | Sat, 8 Mar 2003 10:47:49 +0000 | From | Russell King <> | Subject | PCI driver module unload race? |
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Hi,
What prevents the following scenario from happening? It's purely theoretical - I haven't seen this occuring.
- Load PCI driver.
- PCI driver registers using pci_module_init(), and adds itself to sysfs.
- Hot-plugin a PCI device which uses this driver. sysfs matches the PCI driver, and calls the PCI drivers probe function.
- The probe function calls kmalloc or some other function which sleeps (or gets preempted, if CONFIG_PREEMPT is enabled.)
- We switch to another thread, which happens to be rmmod for this PCI driver. We remove the driver since it has a use count of zero.
- We switch back to the PCI driver. Oops.
I've probably missed something, but I don't think so. I suspect we need struct device_driver to include a struct module pointer which sysfs can take before calling any driver functions.
Comments?
-- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html
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