Re: [PATCH -tip V2] [BUGFIX] kprobes/x86: Do not jump-optimize kprobes on irq entry code

[kbuild test robot]

Hi Masami,

[auto build test ERROR on tip/auto-latest]
[also build test ERROR on v4.13-rc2 next-20170725]
[cannot apply to tip/x86/core]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Masami-Hiramatsu/kprobes-x86-Do-not-jump-optimize-kprobes-on-irq-entry-code/20170725-231634
config: x86_64-randconfig-x018-201730 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   arch/x86//kernel/kprobes/opt.c: In function 'can_optimize':
>> arch/x86//kernel/kprobes/opt.c:259:32: error: '__irqentry_text_start' undeclared (first use in this function)
         ((paddr >= (unsigned long)__irqentry_text_start) &&
                                   ^~~~~~~~~~~~~~~~~~~~~
   arch/x86//kernel/kprobes/opt.c:259:32: note: each undeclared identifier is reported only once for each function it appears in
>> arch/x86//kernel/kprobes/opt.c:260:32: error: '__irqentry_text_end' undeclared (first use in this function)
          (paddr <  (unsigned long)__irqentry_text_end)))
                                   ^~~~~~~~~~~~~~~~~~~

vim +/__irqentry_text_start +259 arch/x86//kernel/kprobes/opt.c

   241	
   242	/* Decode whole function to ensure any instructions don't jump into target */
   243	static int can_optimize(unsigned long paddr)
   244	{
   245		unsigned long addr, size = 0, offset = 0;
   246		struct insn insn;
   247		kprobe_opcode_t buf[MAX_INSN_SIZE];
   248	
   249		/* Lookup symbol including addr */
   250		if (!kallsyms_lookup_size_offset(paddr, &size, &offset))
   251			return 0;
   252	
   253		/*
   254		 * Do not optimize in the entry code due to the unstable
   255		 * stack handling and registers setup.
   256		 */
   257		if (((paddr >= (unsigned long)__entry_text_start) &&
   258		     (paddr <  (unsigned long)__entry_text_end)) ||
 > 259		    ((paddr >= (unsigned long)__irqentry_text_start) &&
 > 260		     (paddr <  (unsigned long)__irqentry_text_end)))
   261			return 0;
   262	
   263		/* Check there is enough space for a relative jump. */
   264		if (size - offset < RELATIVEJUMP_SIZE)
   265			return 0;
   266	
   267		/* Decode instructions */
   268		addr = paddr - offset;
   269		while (addr < paddr - offset + size) { /* Decode until function end */
   270			unsigned long recovered_insn;
   271			if (search_exception_tables(addr))
   272				/*
   273				 * Since some fixup code will jumps into this function,
   274				 * we can't optimize kprobe in this function.
   275				 */
   276				return 0;
   277			recovered_insn = recover_probed_instruction(buf, addr);
   278			if (!recovered_insn)
   279				return 0;
   280			kernel_insn_init(&insn, (void *)recovered_insn, MAX_INSN_SIZE);
   281			insn_get_length(&insn);
   282			/* Another subsystem puts a breakpoint */
   283			if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION)
   284				return 0;
   285			/* Recover address */
   286			insn.kaddr = (void *)addr;
   287			insn.next_byte = (void *)(addr + insn.length);
   288			/* Check any instructions don't jump into target */
   289			if (insn_is_indirect_jump(&insn) ||
   290			    insn_jump_into_range(&insn, paddr + INT3_SIZE,
   291						 RELATIVE_ADDR_SIZE))
   292				return 0;
   293			addr += insn.length;
   294		}
   295	
   296		return 1;
   297	}
   298	

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0-DAY kernel test infrastructure                Open Source Technology Center
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