In the Linux kernel, the following vulnerability has been resolved:
perf/core: Exit early on perf_mmap() fail
When perfmmap() fails to allocate a buffer, it still invokes the eventmapped() callback of the related event. On X86 this might increase the perfrdpmcallowed reference counter. But nothing undoes this as perfmmapclose() is never called in this case, which causes another reference count leak.
Return early on failure to prevent that.