Messages in this thread | | | Date | Tue, 15 Jul 2014 10:20:56 +0900 | From | Masami Hiramatsu <> | Subject | Re: Re: [RFC][PATCH 0/3] ftrace: Add dynamically allocated trampolines |
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(2014/07/14 23:18), Namhyung Kim wrote: > 2014-07-14 (월), 17:18 +0900, Masami Hiramatsu: >> (2014/07/14 16:16), Namhyung Kim wrote: >>> Hi Masami, >>> >>> On Mon, 14 Jul 2014 10:35:21 +0900, Masami Hiramatsu wrote: >>>> (2014/07/11 23:29), Josh Poimboeuf wrote: >>>>> Here's the same stack trace with this patch: >>>>> >>>>> [ 1314.612287] [<ffffffff81700312>] dump_stack+0x45/0x56 >>>>> [ 1314.612290] [<ffffffff8125f5b0>] ? meminfo_proc_open+0x30/0x30 >>>>> [ 1314.612293] [<ffffffffa080a494>] kpatch_ftrace_handler+0x14/0xf0 [kpatch] >>>>> [ 1314.612306] [<ffffffffa00160c4>] 0xffffffffa00160c3 >>>> >>>> Here, this still has a wrong entry. Maybe the trampline doesn't setup >>>> frame pointer (bp) correctly. >>> >>> Hmm.. are you saying about the hex address above? I guess it's a valid >>> entry in the (dynamic) trampoline, but has no symbol.. >> >> Ah, indeed. (BTW, why is it one less than the address ...? printk's spec?) > > Argh, it seems like a bug in printk's %pB format processing.. :-/ > > It subtract 1 from the address for stacktrace. Please see the commit > 0f77a8d37825 ("vsprintf: Introduce %pB format specifier") and > 71f9e59800e5 ("x86, dumpstack: Use %pB format specifier for stack > trace") for details. But it should restore the original address when it > failed to find a symbol for that address.
Ah I see.
> > I'll send a fix soon.
Thanks! :)
-- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Research Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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