On Wed, Sep 04, 2019 at 02:46:18PM -0700, Song Liu wrote: > perf_mmap() always increases user->locked_vm. As a result, "extra" could > grow bigger than "user_extra", which doesn't make sense. Here is an > example case: > > Note: Assume "user_lock_limit" is very small. > | # of perf_mmap calls |vma->vm_mm->pinned_vm|user->locked_vm| > | 0 | 0 | 0 | > | 1 | user_extra | user_extra | > | 2 | 3 * user_extra | 2 * user_extra| > | 3 | 6 * user_extra | 3 * user_extra| > | 4 | 10 * user_extra | 4 * user_extra| > > Fix this by maintaining proper user_extra and extra.
Aah, indeed. Also, this code is unreadable (which is mostly my own fault I suppose) :/
