Syzbot reports many UAF issues for workqueue or timer, see [1] and [2]. In some of these access/allocation happened in process_one_work(), we see the free stack is useless in KASAN report, it doesn't help programmers to solve UAF on workqueue. The same may stand for times.
This patchset improves KASAN reports by making them to have workqueue queueing stack and timer queueing stack information. It is useful for programmers to solve use-after-free or double-free memory issue. Generic KASAN will record the last two workqueue and timer stacks, print them in KASAN report. It is only suitable for generic KASAN. [1]https://groups.google.com/g/syzkaller-bugs/search?q=%22use-after-free%22+process_one_work [2]https://groups.google.com/g/syzkaller-bugs/search?q=%22use-after-free%22%20expire_timers [3]https://bugzilla.kernel.org/show_bug.cgi?id=198437 Walter Wu (6): timer: kasan: record timer stack workqueue: kasan: record workqueue stack kasan: print timer and workqueue stack lib/test_kasan.c: add timer test case lib/test_kasan.c: add workqueue test case kasan: update documentation for generic kasan --- Changes since v1: - Thanks for Marco and Thomas suggestion. - Remove unnecessary code and fix commit log - reuse kasan_record_aux_stack() and aux_stack to record timer and workqueue stack. - change the aux stack title for common name. --- Documentation/dev-tools/kasan.rst | 4 ++-- kernel/time/timer.c | 3 +++ kernel/workqueue.c | 3 +++ lib/test_kasan.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ mm/kasan/report.c | 4 ++-- 5 files changed, 64 insertions(+), 4 deletions(-)
