Vlastimil Babka 0fe9a448a0 mm, page_owner: decouple freeing stack trace from debug_pagealloc ... Commit 8974558f49 ("mm, page_owner, debug_pagealloc: save and dump freeing stack trace") enhanced page_owner to also store freeing stack trace, when debug_pagealloc is also enabled. KASAN would also like to do this [1] to improve error reports to debug e.g. UAF issues. Kirill has suggested that the freeing stack trace saving should be also possible to be enabled separately from KASAN or debug_pagealloc, i.e. with an extra boot option. Qian argued that we have enough options already, and avoiding the extra overhead is not worth the complications in the case of a debugging option. Kirill noted that the extra stack handle in struct page_owner requires 0.1% of memory. This patch therefore enables free stack saving whenever page_owner is enabled, regardless of whether debug_pagealloc or KASAN is also enabled. KASAN kernels booted with page_owner=on will thus benefit from the improved error reports. [1] https://bugzilla.kernel.org/show_bug.cgi?id=203967 [vbabka@suse.cz: v3] Link: http://lkml.kernel.org/r/20191007091808.7096-3-vbabka@suse.cz Link: http://lkml.kernel.org/r/20190930122916.14969-3-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Qian Cai <cai@lca.pw> Suggested-by: Dmitry Vyukov <dvyukov@google.com> Suggested-by: Walter Wu <walter-zh.wu@mediatek.com> Suggested-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Suggested-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2019-10-14 15:04:00 -07:00
..
coccinelle.rst	doc:process: add links where missing	2018-12-06 10:21:19 -07:00
gcov.rst	gcov: docs: add a note on GCC vs Clang differences	2019-05-14 19:52:51 -07:00
gdb-kernel-debugging.rst	docs: disable KASLR when debugging kernel	2017-07-17 14:49:01 -06:00
index.rst	Documentation: dev-tools: Fix typos in index.rst	2018-11-25 12:27:05 -07:00
kasan.rst	mm, page_owner: decouple freeing stack trace from debug_pagealloc	2019-10-14 15:04:00 -07:00
kcov.rst	Documentation/dev-tools: Use gcc version number instead svn revision number	2019-01-14 17:25:41 -07:00
kgdb.rst	docs: disable KASLR when debugging kernel	2017-07-17 14:40:40 -06:00
kmemleak.rst	docs: kmemleak: add more documentation details	2019-07-12 11:05:42 -07:00
kselftest.rst	kselftest: add capability to skip chosen TARGETS	2019-10-01 13:19:04 -06:00
sparse.rst	Remove references to dead website.	2019-07-19 12:22:04 -07:00
ubsan.rst