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Message-ID: <1500523343.2055.2.camel@gmail.com>
Subject: Re: [lkp-robot] [include/linux/string.h]  6974f0c455:
 kernel_BUG_at_lib/string.c
From: Daniel Micay <danielmicay@gmail.com>
To: kernel test robot <xiaolong.ye@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>, Arnd Bergmann <arnd@arndb.de>,
        Mark Rutland <mark.rutland@arm.com>, Daniel Axtens <dja@axtens.net>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Chris Metcalf <cmetcalf@ezchip.com>,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
        Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>, lkp@01.org
Date: Thu, 20 Jul 2017 00:02:23 -0400
In-Reply-To: <20170720014238.GH27396@yexl-desktop>
References: <20170720014238.GH27396@yexl-desktop>
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> [    8.134886]  arch_prepare_optimized_kprobe+0xd5/0x171
> [    8.134886]  arch_prepare_optimized_kprobe+0xd5/0x171

Probably this:

	/* Copy arch-dep-instance from template */
	memcpy(buf, &optprobe_template_entry, TMPL_END_IDX);

Not a real bug, just technically undefined because these are u32:

typedef u32 kprobe_opcode_t;

extern __visible kprobe_opcode_t optprobe_template_entry;
extern __visible kprobe_opcode_t optprobe_template_val;
extern __visible kprobe_opcode_t optprobe_template_call;
extern __visible kprobe_opcode_t optprobe_template_end;
extern __visible kprobe_opcode_t optprobe_template_sub_sp;
extern __visible kprobe_opcode_t optprobe_template_add_sp;
extern __visible kprobe_opcode_t optprobe_template_restore_begin;
extern __visible kprobe_opcode_t optprobe_template_restore_orig_insn;
extern __visible kprobe_opcode_t optprobe_template_restore_end;

Could be switched to unknown size arrays like optprobe_template_entry[]
but it might be best to just mark the kprobe code with #define
__NO_FORTIFY.