This is related to CONFIG_DEBUG_OBJECTS but may be relevant for other debug configs as well. We should use lib/stackdepot.c (CONFIG_STACKDEPOT) in more debugging facilities to memorize full stack traces. stackdepot maps a full stack trace to an u32 (i.e. smaller than memorizing a single PC). In particular come up in the context of: https://syzkaller.appspot.com/bug?extid=c4521ac872a4ccc3afec https://groups.google.com/forum/#!msg/syzkaller-bugs/0T-seeO7cwc/X82YaRNWBAAJ which contains just: ------------[ cut here ]------------ ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x90 arch/x86/include/asm/paravirt.h:767 and then Thomas says: "One of the cleaned up devices has left an active timer which belongs to a delayed work. That's all I can decode out of that splat. :(" Presumably having a full stack for the timer allocation would make this actionable.