Hey- I happened to notice that the ibmphp hotplug driver does something rather silly in its init routine. It purposely calls module_put so as to underflow its module ref count to avoid being removed from the kernel. This is bad practice, and wrong, since it provides a window for subsequent module_gets to reset the refcount to zero, allowing an unload to race in and cause all sorts of mysterious panics. If the module is unsafe to load, it should inform the kernel as such with a call to __unsafe. The patch below does that. Regards Neil Signed-off-by: Neil Horman <nhorman@xxxxxxxxxxxxx> ibmphp_core.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/pci/hotplug/ibmphp_core.c b/drivers/pci/hotplug/ibmphp_core.c index c892daa..3706d4e 100644 --- a/drivers/pci/hotplug/ibmphp_core.c +++ b/drivers/pci/hotplug/ibmphp_core.c @@ -1402,9 +1402,11 @@ static int __init ibmphp_init(void) goto error; } - /* lock ourselves into memory with a module - * count of -1 so that no one can unload us. */ - module_put(THIS_MODULE); + /* + * Its unsafe to unload this module, so tell + * the kernel to avoid inadvertent unloads + */ + __unsafe(THIS_MODULE); exit: return rc; -- /**************************************************** * Neil Horman <nhorman@xxxxxxxxxxxxx> * Software Engineer, Red Hat ****************************************************/ -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
