Messages in this thread | | | Date | Fri, 11 Jul 2014 15:24:28 +0200 (CEST) | From | Jiri Kosina <> | Subject | Re: [RFC][PATCH 0/3] ftrace: Add dynamically allocated trampolines |
| |
On Fri, 11 Jul 2014, Masami Hiramatsu wrote:
> >> I did some testing with kpatch and I found one minor issue. The dynamically > >> allocated trampoline seems to confuse dump_stack() somewhat. > >> > >> I added a dump_stack() call in my ftrace_ops callback function > >> (kpatch_ftrace_handler) which had a filter on meminfo_proc_show(). > > > > Interesting. Are you using dwarf2 unwinder for stack dumping by any > > chance? It seems to get things right here. Will look into it more > > tomorrow. > > Hmm, can dwarf2 unwinder work on the trampoline method? Since the > trampoline just a copy of instructions which will not have CFI(which is > stored in dwarf section), I guess it may not work... Frame pointer (push > bp and save sp to bp on the entry) can work anyway.
That was exactly my idea and that's why I asked, thanks for confirming.
I am afraid we'll have to declare dynamic trampolines incompatible with drawf2 stack dumping.
-- Jiri Kosina SUSE Labs
| |