Adds a test to verify workqueue stack recording and print it in KASAN report. The KASAN report was as follows(cleaned up slightly): BUG: KASAN: use-after-free in kasan_workqueue_uaf Freed by task 54: kasan_save_stack+0x24/0x50 kasan_set_track+0x24/0x38 kasan_set_free_info+0x20/0x40 __kasan_slab_free+0x10c/0x170 kasan_slab_free+0x10/0x18 kfree+0x98/0x270 kasan_workqueue_work+0xc/0x18 Last potentially related work creation: kasan_save_stack+0x24/0x50 kasan_record_wq_stack+0xa8/0xb8 insert_work+0x48/0x288 __queue_work+0x3e8/0xc40 queue_work_on+0xf4/0x118 kasan_workqueue_uaf+0xfc/0x190 Link: https://lkml.kernel.org/r/20201203022748.30681-1-walter-zh.wu@mediatek.com Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com> Acked-by: Marco Elver <elver@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>