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From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
To: "Suzuki K. Poulose" <suzuki@in.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Tony Luck <tony.luck@gmail.com>,
	Jeremy Fitzhardinge <jeremy@goop.org>,
	linux-ia64@vger.kernel.org, sparse@chrisli.org,
	"H. Peter Anvin" <hpa@zytor.com>,
	akataria@vmware.com, 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,
	Thomas Gleixner <tglx@linutronix.de>,
	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 v2] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64
Date: Fri, 30 May 2014 11:47:44 +0900
Message-ID: <5387F150.5000307@hitachi.com> (raw)
In-Reply-To: <538786D8.1070303@in.ibm.com>

(2014/05/30 4:13), Suzuki K. Poulose wrote:
>> @@ -2042,7 +2043,8 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
>>  	unsigned long offset = 0, size = 0;
>>  
>>  	for (iter = start; iter < end; iter++) {
>> -		if (!kallsyms_lookup_size_offset(*iter, &size, &offset)) {
>> +		if (!kallsyms_lookup_size_offset(function_entry(*iter),
>> +						 &size, &offset)) {
> 
> On powerpc we will be able to resolve the *iter to func_descr and won't
> get the below error with/without this patch. So we have to actually
> verify the kprobe_blacklist contents to make sure everything is alright.
> 
>>  			pr_err("Failed to find blacklist %p\n", (void *)*iter);
>>  			continue;
>>  		}
>>
> 
> There is a bug here.
> You need to set the ent->start using the function_entry(*iter) and not
> *iter. Or else you just avoid the 'Warning' and still have an invalid
> black list. As shown below :
> 
>     2e:mon> ls kprobe_blacklist
>     kprobe_blacklist: c00000000104dad0
>     2e:mon> d c00000000104dad0 10
>     c00000000104dad0: c0000003aff800a0 c0000003aff809a0
>     2e:mon> d c0000003aff800a0 20 (struct kprobe_blacklist *)
>     c0000003aff800a0: c0000003aff800c0 c00000000104dad0
>     c0000003aff800b0: c0000000010ef138 c0000000010ef188
>                       start ^^         end ^^
>     2e:mon> la c0000000010ef138 (start)
>     c0000000010ef138: notify_die+0x0/0x10 <- still points to the
> function descriptor
>     2e:mon> la c0000000010ef188 (end)
>     c0000000010ef188: __blocking_notifier_call_chain+0x0/0x10
> 
> 
> Following patch fixes the issue, with the patch :
> 
> 1:mon> ls kprobe_blacklist
> kprobe_blacklist: c00000000104dad0
> 1:mon> d c00000000104dad0 10
> c00000000104dad0: c0000003ae1a00a0 c0000003ae1a09a0
> 1:mon> d c0000003ae1a00a0 20 (struct kprobe_blacklist *)
> c0000003ae1a00a0: c0000003ae1a00c0 c00000000104dad0
> c0000003ae1a00b0: c0000000000b14d0 c0000000000b1520
>                       start ^^         end ^^
> 1:mon> la c0000000000b14d0
> c0000000000b14d0: .notify_die+0x0/0x50
> 1:mon> la c0000000000b1520
> c0000000000b1520: .atomic_notifier_chain_register+0x0/0xa0
> 
> 1:mon> di c0000000000b14d0 10 (.notify_die)
> c0000000000b14d0  7c0802a6	mflr	r0
> c0000000000b14d4  7c691b78	mr	r9,r3
> 
> commit ed51674aca8e0496641f565421ab6691a873e80a
> Author: Suzuki K. Poulose <suzuki@in.ibm.com>
> Date:   Fri May 30 00:23:01 2014 +0530
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 3859c88..b81d626 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -2043,7 +2043,8 @@ static int __init
> populate_kprobe_blacklist(unsigned long *start,
>         unsigned long offset = 0, size = 0;
> 
>         for (iter = start; iter < end; iter++) {
> -               if (!kallsyms_lookup_size_offset(function_entry(*iter),
> +               unsigned long entry = function_entry(*iter);
> +               if (!kallsyms_lookup_size_offset(entry,
>                                                  &size, &offset)) {
>                         pr_err("Failed to find blacklist %p\n", (void
> *)*iter);
>                         continue;
> @@ -2052,8 +2053,8 @@ static int __init
> populate_kprobe_blacklist(unsigned long *start,
>                 ent = kmalloc(sizeof(*ent), GFP_KERNEL);
>                 if (!ent)
>                         return -ENOMEM;
> -               ent->start_addr = *iter;
> -               ent->end_addr = *iter + size;
> +               ent->start_addr = entry;
> +               ent->end_addr = entry + size;

Oops! right, I missed it :(
I'll update the patch including your fix and signed-off-by.

thank you!


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com



  reply index

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 [this message]
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
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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