Re: [v3 PATCH 05/10] x86/insn-kernel: Add support to resolve 16-bit addressing encodings (fwd)

[Julia Lawall]

Check the type of seg on line 267.

julia

---------- Forwarded message ----------
Date: Thu, 26 Jan 2017 05:24:40 +0800
From: kbuild test robot <fengguang.wu@xxxxxxxxx>
To: kbuild@xxxxxx
Cc: Julia Lawall <julia.lawall@xxxxxxx>
Subject: Re: [v3 PATCH 05/10] x86/insn-kernel: Add support to resolve 16-bit
    addressing encodings

In-Reply-To: <20170125202353.101059-6-ricardo.neri-calderon@xxxxxxxxxxxxxxx>

Hi Ricardo,

[auto build test WARNING on tip/auto-latest]
[also build test WARNING on v4.10-rc5 next-20170125]
[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/Ricardo-Neri/x86-Enable-User-Mode-Instruction-Prevention/20170126-043345
:::::: branch date: 51 minutes ago
:::::: commit date: 51 minutes ago

>> arch/x86/lib/insn-kernel.c:267:6-9: WARNING: Unsigned expression compared with zero: seg < 0

git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 574de0de238ef30c816985006f02f7a1dbba92aa
vim +267 arch/x86/lib/insn-kernel.c

574de0de Ricardo Neri 2017-01-25  251  		addr = (seg << 4) + regs_get_register(regs, addr_offset1);
574de0de Ricardo Neri 2017-01-25  252  	} else {
574de0de Ricardo Neri 2017-01-25  253  		ret = get_reg_offset_16(insn, regs, &addr_offset1,
574de0de Ricardo Neri 2017-01-25  254  					&addr_offset2);
574de0de Ricardo Neri 2017-01-25  255  		if (ret < 0)
574de0de Ricardo Neri 2017-01-25  256  			goto out_err;
574de0de Ricardo Neri 2017-01-25  257  		/*
574de0de Ricardo Neri 2017-01-25  258  		 * Don't fail on invalid offset values. They might be invalid
574de0de Ricardo Neri 2017-01-25  259  		 * because they are not supported. Instead, use them in the
574de0de Ricardo Neri 2017-01-25  260  		 * calculation only if they contain a valid value.
574de0de Ricardo Neri 2017-01-25  261  		 */
574de0de Ricardo Neri 2017-01-25  262  		if (addr_offset1 >= 0)
574de0de Ricardo Neri 2017-01-25  263  			addr1 = regs_get_register(regs, addr_offset1);
574de0de Ricardo Neri 2017-01-25  264  		if (addr_offset2 >= 0)
574de0de Ricardo Neri 2017-01-25  265  			addr2 = regs_get_register(regs, addr_offset2);
574de0de Ricardo Neri 2017-01-25  266  		seg = __get_segment_selector_16(regs, insn, addr_offset1);
574de0de Ricardo Neri 2017-01-25 @267  		if (seg < 0)
574de0de Ricardo Neri 2017-01-25  268  			goto out_err;
574de0de Ricardo Neri 2017-01-25  269  		addr =  (seg << 4) + addr1 + addr2;
574de0de Ricardo Neri 2017-01-25  270  	}
574de0de Ricardo Neri 2017-01-25  271  	addr += insn->displacement.value;
574de0de Ricardo Neri 2017-01-25  272
574de0de Ricardo Neri 2017-01-25  273  	return (void __user *)addr;
574de0de Ricardo Neri 2017-01-25  274  out_err:
574de0de Ricardo Neri 2017-01-25  275  	return (void __user *)-1;

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