Mathieu Poirier <[email protected]> writes: > On Thu, Jan 26, 2017 at 11:40:57AM +0200, Alexander Shishkin wrote: >> + if (!ifh->nr_file_filters) >> + return; > > Is this mandatory or an optimisation to avoid circling through a list of > filters > that don't included user space files?
It's both. It stems from the fact that the remainder of this function relies on ctx::task not being NULL, which is not the case with cpu contexts and now that we've enabled address filters for such contexts, it's a problem. So checking for !task would have done the trick here, but this way we'll also avoid going down this path for task contexts in the absence of file-based filters. In particular, grabbing the mmap semaphore and filters spinlock we can do without. Regards, -- Alex
