Kefeng Wang reported that he was seeing some memory leaks with kmemleak with page_owner enabled. The reason is that we enable the page_owner_inited static branch and then proceed with the linking of stack_list struct to dummy_stack, which means that exists a race window between these two steps where we can have pages already being allocated calling add_stack_record_to_list(), allocating objects and linking them to stack_list, but then we set stack_list pointing to dummy_stack in init_page_owner. Which means that the objects that have been allocated during that time window are unreferenced and lost. Fix this by deferring the enablement of the branch until we have properly set up the list. Link: https://lkml.kernel.org/r/20240409131715.13632-1-osalvador@suse.de Fixes: 4bedfb314bdd ("mm,page_owner: maintain own list of stack_records structs") Signed-off-by: Oscar Salvador <osalvador@suse.de> Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com> Closes: https://lore.kernel.org/linux-mm/74b147b0-718d-4d50-be75-d6afc801cd24@huawei.com/ Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the reStructuredText markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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