Catalin Marinas <catalin.marinas@xxxxxxx> writes: > On Mon, May 11, 2020 at 09:15:55PM +1000, Michael Ellerman wrote: >> Qian Cai <cai@xxxxxx> writes: >> > kvmppc_pmd_alloc() and kvmppc_pte_alloc() allocate some memory but then >> > pud_populate() and pmd_populate() will use __pa() to reference the newly >> > allocated memory. The same is in xive_native_provision_pages(). >> > >> > Since kmemleak is unable to track the physical memory resulting in false >> > positives, silence those by using kmemleak_ignore(). >> >> There is kmemleak_alloc_phys(), which according to the docs can be used >> for tracking a phys address. > > This won't help. While kmemleak_alloc_phys() allows passing a physical > address, it doesn't track physical address references to this object. It > still expects VA pointing to it, otherwise the object would be reported > as a leak. OK, thanks for clarifying that. > We currently only call this from the memblock code with a min_count of > 0, meaning it will not be reported as a leak if no references are found. > > We don't have this issue with page tables on other architectures since > most of them use whole page allocations which aren't tracked by > kmemleak. These powerpc functions use kmem_cache_alloc() which would be > tracked automatically by kmemleak. While we could add a phys alias to > kmemleak (another search tree), I think the easiest is as per Qian's > patch, just ignore those objects. Agreed. cheers
