The debug_pagealloc functionality serves a similar purpose on the page allocator level that slub_debug does on the kmalloc level, which is to detect bad users. One notable feature that slub_debug has is storing stack traces of who last allocated and freed the object. On page level we track allocations via page_owner, but that info is discarded when freeing, and we don't track freeing at all. This series improves those aspects. With both debug_pagealloc and page_owner enabled, we can then get bug reports such as the example in Patch 3. SLUB debug tracking additionaly stores cpu, pid and timestamp. This could be added later, if deemed useful enough to justify the additional page_ext structure size. Vlastimil Babka (3): mm, page_owner: record page owner for each subpage mm, page_owner: keep owner info when freeing the page mm, page_owner, debug_pagealloc: save and dump freeing stack trace .../admin-guide/kernel-parameters.txt | 2 + include/linux/page_ext.h | 1 + mm/Kconfig.debug | 4 +- mm/page_owner.c | 123 +++++++++++++----- 4 files changed, 96 insertions(+), 34 deletions(-) -- 2.22.0
