在 2018-03-22四的 22:21 +0000，James Hogan写道：
On Fri, Mar 16, 2018 at 03:55:16PM +0800, Huacai Chen wrote:
diff --git a/arch/mips/boot/compressed/decompress.c b/arch/mips/boot/compressed/decompress.c index fdf99e9..5ba431c 100644 --- a/arch/mips/boot/compressed/decompress.c +++ b/arch/mips/boot/compressed/decompress.c @@ -78,11 +78,6 @@ void error(char *x) unsigned long __stack_chk_guard;
...
diff --git a/arch/mips/boot/compressed/head.S b/arch/mips/boot/compressed/head.S index 409cb48..00d0ee0 100644 --- a/arch/mips/boot/compressed/head.S +++ b/arch/mips/boot/compressed/head.S @@ -32,6 +32,10 @@ start: bne a2, a0, 1b addiu a0, a0, 4
- PTR_LA a0, __stack_chk_guard
- PTR_LI a1, 0x000a0dff
- sw a1, 0(a0)
Hi James
Huacai Can't reply this mail. His chenhc@lemote.com is blcoked by Linux-MIPS mailing list while his Gmail didn't receive this email, so I'm replying for him.
Should that not be LONG_S? Otherwise big endian MIPS64 would get a word-swapped canary (which is probably mostly harmless, but still).
Yes, he said it's considerable.
Also I think it worth mentioning in the commit message the MIPS configuration you hit this with, presumably a Loongson one? For me decompress_kernel() gets a stack guard on loongson3_defconfig, but not malta_defconfig or malta_defconfig + 64-bit. I presume its sensitive to the compiler inlining stuff into decompress_kernel() or something such that it suddenly qualifies for a stack guard.
Have you tested with CONFIG_CC_STACKPROTECTOR_STRONG=y ? Huacai reproduced the issue by this[1] config with GCC 4.9.
[1] https://github.com/loongson-community/linux-stable/blob/rebase-4.14 /arch/mips/configs/loongson3_defconfig
Cheers James