From mboxrd@z Thu Jan  1 00:00:00 1970
From: Michael Ellerman <mpe@ellerman.id.au>
Date: Tue, 15 Jul 2014 03:19:30 +0000
Subject: Re: [PATCH v5 2/2] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64
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List-Id: <linux-ia64.vger.kernel.org>
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	 <20140702070029.14689.18485.stgit@kbuild-fedora.novalocal>
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To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.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>, Ingo Molnar <mingo@kernel.org>, linux-tip-commits@vger.kernel.org, akataria@vmware.com, anil.s.keshavamurthy@intel.com, "Suzuki K. Poulose" <suzuki@in.ibm.com>, 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>, Ananth N Mavinakayanahalli <ananth@in.ibm.com>, linuxppc-dev@lists.ozlabs.org, rdunlap@infradead.org, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, dl9pf@gmx.de, Andrew Morton <akpm@linux-foundation.org>, Linus Torvalds <torvalds@linux-foundation.org>, "David S. Miller" <davem@davemloft.net>

On Wed, 2014-07-02 at 07:00 +0000, Masami Hiramatsu wrote:
> On ia64 and ppc64, the function pointer does not point the
> entry address of the function, but the address of function
> discriptor (which contains the entry address and misc
> data.) Since the kprobes passes the function pointer stored
> by NOKPROBE_SYMBOL() to kallsyms_lookup_size_offset() for
> initalizing its blacklist, it fails and reports many errors
> as below.
> 
>   Failed to find blacklist 0001013168300000
>   Failed to find blacklist 0001013000f0a000
>   Failed to find blacklist 000101315f70a000
>   Failed to find blacklist 000101324c80a000
>   Failed to find blacklist 0001013063f0a000
>   Failed to find blacklist 000101327800a000
>   Failed to find blacklist 0001013277f0a000
>   Failed to find blacklist 000101315a70a000
>   Failed to find blacklist 0001013277e0a000
>   Failed to find blacklist 000101305a20a000
>   Failed to find blacklist 0001013277d0a000
>   Failed to find blacklist 00010130bdc0a000
>   Failed to find blacklist 00010130dc20a000
>   Failed to find blacklist 000101309a00a000
>   Failed to find blacklist 0001013277c0a000
>   Failed to find blacklist 0001013277b0a000
>   Failed to find blacklist 0001013277a0a000
>   Failed to find blacklist 000101327790a000
>   Failed to find blacklist 000101303140a000
>   Failed to find blacklist 0001013a3280a000
> 
> To fix this bug, this introduces function_entry() macro to
> retrieve the entry address from the given function pointer,
> and uses for kallsyms_lookup_size_offset() while initializing
> blacklist.
> 
> Changes in v5:
>  - Use arch_deref_entry_point() instead of function_entry().
> 
> Changes in v4:
>  - Add kernel_text_address() check for verifying the address.
>  - Moved on the latest linus tree.
> 
> Changes in v3:
>  - Fix a bug to get blacklist address based on function entry
>    instead of function descriptor. (Suzuki's work, Thanks!)
> 
> Changes in V2:
>  - Use function_entry() macro when lookin up symbols instead
>    of storing it.
>  - Update for the latest -next.
> 
> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Reported-by: Tony Luck <tony.luck@gmail.com>
> Tested-by: Tony Luck <tony.luck@intel.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>

Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (for powerpc)

Ben, can you take this in your tree?

cheers