From: "Suzuki K. Poulose" <suzuki@in.ibm.com>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Tony Luck <tony.luck@gmail.com>,
Paul Mackerras <paulus@samba.org>,
Jeremy Fitzhardinge <jeremy@goop.org>,
linux-ia64@vger.kernel.org, sparse@chrisli.org,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-tip-commits@vger.kernel.org,
anil.s.keshavamurthy@intel.com, Ingo Molnar <mingo@kernel.org>,
Fenghua Yu <fenghua.yu@intel.com>, Arnd Bergmann <arnd@arndb.de>,
Rusty Russell <rusty@rustcorp.com.au>,
Chris Wright <chrisw@sous-sol.org>,
yrl.pp-manager.tt@hitachi.com, akataria@vmware.com,
Tony Luck <tony.luck@intel.com>, Kevin Hao <haokexin@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
rdunlap@infradead.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
dl9pf@gmx.de, Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev@lists.ozlabs.org,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [RFT PATCH -next v3] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64
Date: Thu, 19 Jun 2014 15:15:26 +0530 [thread overview]
Message-ID: <53A2B136.108@in.ibm.com> (raw)
In-Reply-To: <53A2908E.2000806@hitachi.com>
On 06/19/2014 12:56 PM, Masami Hiramatsu wrote:
> (2014/06/19 15:40), Suzuki K. Poulose wrote:
>> On 06/19/2014 10:22 AM, Masami Hiramatsu wrote:
>>> (2014/06/19 10:30), Michael Ellerman wrote:
>>>> On Wed, 2014-06-18 at 17:46 +0900, Masami Hiramatsu wrote:
>>>>> (2014/06/18 16:56), Michael Ellerman wrote:
>>>>>> On Fri, 2014-06-06 at 15:38 +0900, Masami Hiramatsu wrote:
>>>>>>> Ping?
>>>>>>>
>>>>>>> I guess this should go to 3.16 branch, shouldn't it?
>>>>>>
>>>>>>>> diff --git a/arch/powerpc/include/asm/types.h b/arch/powerpc/include/asm/types.h
>>>>>>>> index bfb6ded..8b89d65 100644
>>>>>>>> --- a/arch/powerpc/include/asm/types.h
>>>>>>>> +++ b/arch/powerpc/include/asm/types.h
>>>>>>>> @@ -25,6 +25,17 @@ typedef struct {
>>>>>>>> unsigned long env;
>>>>>>>> } func_descr_t;
>>>>>>>>
>>>>>>>> +#if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF == 1)
>>>>>>>> +/*
>>>>>>>> + * On PPC64 ABIv1 the function pointer actually points to the
>>>>>>>> + * function's descriptor. The first entry in the descriptor is the
>>>>>>>> + * address of the function text.
>>>>>>>> + */
>>>>>>>> +#define function_entry(fn) (((func_descr_t *)(fn))->entry)
>>>>>>>> +#else
>>>>>>>> +#define function_entry(fn) ((unsigned long)(fn))
>>>>>>>> +#endif
>>>>>>
>>>>>> We already have ppc_function_entry(), can't you use that?
>>>>>
>>>>> I'd like to ask you whether the address which ppc_function_entry() returns on
>>>>> PPC ABIv2 is really same address in kallsyms or not.
>>>>> As you can see, kprobes uses function_entry() to get the actual entry address
>>>>> where kallsyms knows. I have not much information about that, but it seems that
>>>>> the "global entry point" is the address which kallsyms knows, isn't it?
>>>>
>>>> OK. I'm not sure off the top of my head which address kallsyms knows about, but
>>>> yes it's likely that it is the global entry point.
>>>>
>>>> I recently sent a patch to add ppc_global_function_entry(), because we need it
>>>> in the ftrace code. Once that is merged you could use that.
>>>
>>> Yeah, I could use that. But since this is used in arch-independent code (e.g. IA64
>>> needs similar macro), I think we'd better define function_entry() in asm/types.h for
>>> general use (for kallsyms), and rename ppc_function_entry to local_function_entry()
>>> in asm/code-patching.h.
>>>
>>>
>>>> How do you hit the original problem, you don't actually specify in your commit
>>>> message? Something with kprobes obviously, but what exactly? I'll try and
>>>> reproduce it here.
>>>
>>> Ah, those messages should be shown in dmesg when booting if it doesn't work,
>>> because the messages are printed by initialization process of kprobe blacklist.
>>> So, reproducing it is just enabling CONFIG_KPROBES and boot it.
>> Well, we don't get those messages on Power, since the kallsyms has the
>> entries for ".function_name". The correct way to verify is, either :
>
> Hmm, that seems another issue on powerpc. Is that expected(and designed)
> behavior?
AFAIK, yes, it is.
To be more precise :
we have 'foo' and '.foo' for a function foo(), where 'foo' points to the
function_entry and '.foo' points to the actual function.
So, a kallsyms_lookup_size_offset() on both 'foo' and '.foo' will return
a hit. So, if we make sure we use the value of '.foo' (by using the
appropriate macros) we should be fine.
And if so, how I can verify when initializing blacklist?
> (should I better use kallsyms_lookup() and kallsyms_lookup_name() for
> verification?)
One way to verify would be to make sure the symbol starts with '.' from
the result of the current kallsyms_lookup_size_offset() for PPC.
Thanks
Suzuki
>
> Thank you,
>
>>
>> 1) Dump the black_list via xmon ( see :
>> https://lkml.org/lkml/2014/5/29/893 ) and verify the entries.
>>
>> or
>>
>> 2) Issue a kprobe on a black listed entry and hit a success,(which we
>> will, since we don't check the actual function address).
>>
>> Thanks
>> Suzuki
>>
>>
>>>
>>> Thank you,
>>>
next prev parent reply other threads:[~2014-06-19 9:47 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-17 8:16 [PATCH -tip v9 00/26] kprobes: introduce NOKPROBE_SYMBOL, bugfixes and scalbility efforts Masami Hiramatsu
2014-04-17 8:16 ` [PATCH -tip v9 01/26] [BUGFIX]kprobes/x86: Fix page-fault handling logic Masami Hiramatsu
2014-04-17 9:58 ` [tip:perf/urgent] kprobes/x86: " tip-bot for Masami Hiramatsu
2014-04-17 8:16 ` [PATCH -tip v9 02/26] kprobes/x86: Allow to handle reentered kprobe on singlestepping Masami Hiramatsu
2014-04-24 10:57 ` [tip:perf/kprobes] kprobes/x86: Allow to handle reentered kprobe on single-stepping tip-bot for Masami Hiramatsu
2014-04-17 8:16 ` [PATCH -tip v9 03/26] kprobes: Prohibit probing on .entry.text code Masami Hiramatsu
2014-04-24 10:57 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 04/26] kprobes: Introduce NOKPROBE_SYMBOL() macro for blacklist Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist tip-bot for Masami Hiramatsu
2014-05-01 5:26 ` kprobes broken in linux-next (was Re: [tip:perf/kprobes] kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist) Vineet Gupta
2014-05-02 1:13 ` Masami Hiramatsu
2014-05-07 4:56 ` Vineet Gupta
2014-05-07 19:18 ` [tip:perf/kprobes] kprobes: Ensure blacklist data is aligned tip-bot for Vineet Gupta
2014-05-05 20:48 ` [tip:perf/kprobes] kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist Tony Luck
2014-05-06 9:25 ` Masami Hiramatsu
2014-05-06 10:03 ` Masami Hiramatsu
2014-05-07 11:19 ` Masami Hiramatsu
2014-05-07 11:55 ` [RFT PATCH -next ] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64 Masami Hiramatsu
2014-05-07 11:59 ` Masami Hiramatsu
2014-05-14 8:19 ` Masami Hiramatsu
2014-05-08 4:47 ` Ananth N Mavinakayanahalli
2014-05-08 5:40 ` Masami Hiramatsu
2014-05-08 6:16 ` Ananth N Mavinakayanahalli
2014-05-09 8:06 ` Masami Hiramatsu
2014-05-26 11:25 ` Suzuki K. Poulose
2014-05-26 11:48 ` Masami Hiramatsu
2014-05-27 6:31 ` [RFT PATCH -next v2] " Masami Hiramatsu
2014-05-29 19:13 ` Suzuki K. Poulose
2014-05-30 2:47 ` Masami Hiramatsu
2014-05-30 3:18 ` [RFT PATCH -next v3] " Masami Hiramatsu
2014-06-06 6:38 ` Masami Hiramatsu
2014-06-17 23:03 ` Tony Luck
2014-06-18 7:56 ` Michael Ellerman
2014-06-18 8:46 ` Masami Hiramatsu
2014-06-19 1:30 ` Michael Ellerman
2014-06-19 4:52 ` Masami Hiramatsu
2014-06-19 6:40 ` Suzuki K. Poulose
2014-06-19 7:26 ` Masami Hiramatsu
2014-06-19 9:45 ` Suzuki K. Poulose [this message]
2014-06-19 11:01 ` Masami Hiramatsu
2014-06-19 11:20 ` Masami Hiramatsu
2014-06-20 0:37 ` Michael Ellerman
2014-06-20 2:13 ` Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 05/26] [BUGFIX] kprobes/x86: Prohibit probing on debug_stack_* Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes, x86: Prohibit probing on debug_stack_*() tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 06/26] [BUGFIX] x86: Prohibit probing on native_set_debugreg/load_idt Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes, x86: Prohibit probing on native_set_debugreg()/load_idt() tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 07/26] [BUGFIX] x86: Prohibit probing on thunk functions and restore Masami Hiramatsu
2014-04-24 10:58 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 08/26] kprobes/x86: Call exception handlers directly from do_int3/do_debug Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-24 11:26 ` Jiri Kosina
2014-04-17 8:17 ` [PATCH -tip v9 09/26] x86: Call exception_enter after kprobes handled Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-06-13 17:14 ` Frederic Weisbecker
2014-06-14 5:44 ` Masami Hiramatsu
2014-06-14 6:47 ` [PATCH -tip ] [Bugfix] x86/kprobes: Fix build errors and blacklist context_track_user Masami Hiramatsu
2014-06-14 8:58 ` [tip:perf/urgent] " tip-bot for Masami Hiramatsu
2014-06-16 15:52 ` [PATCH -tip ] [Bugfix] " Frederic Weisbecker
2014-04-17 8:17 ` [PATCH -tip v9 10/26] kprobes/x86: Allow probe on some kprobe preparation functions Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:17 ` [PATCH -tip v9 11/26] kprobes: Allow probe on some kprobe functions Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 12/26] ftrace/*probes: Allow probing on some functions Masami Hiramatsu
2014-04-24 10:59 ` [tip:perf/kprobes] kprobes, ftrace: " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 13/26] x86: Allow kprobes on text_poke/hw_breakpoint Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, x86: Allow kprobes on text_poke/ hw_breakpoint tip-bot for Masami Hiramatsu
2014-04-24 11:26 ` Jiri Kosina
2014-04-17 8:18 ` [PATCH -tip v9 14/26] x86: Use NOKPROBE_SYMBOL() instead of __kprobes annotation Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 15/26] kprobes: Use NOKPROBE_SYMBOL macro instead of __kprobes Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 16/26] ftrace/kprobes: Use NOKPROBE_SYMBOL macro in ftrace Masami Hiramatsu
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, ftrace: " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 17/26] notifier: Use NOKPROBE_SYMBOL macro in notifier Masami Hiramatsu
2014-04-17 14:40 ` Josh Triplett
2014-04-24 11:00 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 18/26] sched: Use NOKPROBE_SYMBOL macro in sched Masami Hiramatsu
2014-04-24 11:01 ` [tip:perf/kprobes] kprobes, " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 19/26] kprobes: Show blacklist entries via debugfs Masami Hiramatsu
2014-04-24 11:01 ` [tip:perf/kprobes] " tip-bot for Masami Hiramatsu
2014-04-17 8:18 ` [PATCH -tip v9 20/26] kprobes: Support blacklist functions in module Masami Hiramatsu
2014-04-24 8:56 ` Ingo Molnar
2014-04-24 11:24 ` Masami Hiramatsu
2014-04-25 8:19 ` Ingo Molnar
2014-04-25 10:12 ` Masami Hiramatsu
2014-04-25 10:55 ` Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 21/26] kprobes: Use NOKPROBE_SYMBOL() in sample modules Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 22/26] kprobes/x86: Use kprobe_blacklist for .kprobes.text and .entry.text Masami Hiramatsu
2014-04-24 8:58 ` Ingo Molnar
2014-04-24 11:22 ` Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 23/26] kprobes/x86: Remove unneeded preempt_disable/enable in interrupt handlers Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 24/26] kprobes: Enlarge hash table to 512 entries Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 25/26] kprobes: Introduce kprobe cache to reduce cache misshits Masami Hiramatsu
2014-04-24 9:01 ` Ingo Molnar
2014-04-24 11:38 ` Masami Hiramatsu
2014-04-25 8:20 ` Ingo Molnar
2014-04-25 9:43 ` Masami Hiramatsu
2014-04-26 7:12 ` Ingo Molnar
2014-04-27 12:49 ` Masami Hiramatsu
2014-04-17 8:19 ` [PATCH -tip v9 26/26] ftrace: Introduce FTRACE_OPS_FL_SELF_FILTER for ftrace-kprobe Masami Hiramatsu
2014-04-17 8:37 ` [PATCH -tip v9 00/26] kprobes: introduce NOKPROBE_SYMBOL, bugfixes and scalbility efforts Ingo Molnar
2014-04-17 8:53 ` Masami Hiramatsu
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