3.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> commit 2cd3949f702692cf4c5d05b463f19cd706a92dd3 upstream. We have some very similarly named command-line options: arch/x86/kernel/cpu/common.c:__setup("noxsave", x86_xsave_setup); arch/x86/kernel/cpu/common.c:__setup("noxsaveopt", x86_xsaveopt_setup); arch/x86/kernel/cpu/common.c:__setup("noxsaves", x86_xsaves_setup); __setup() is designed to match options that take arguments, like "foo=bar" where you would have: __setup("foo", x86_foo_func...); The problem is that "noxsave" actually _matches_ "noxsaves" in the same way that "foo" matches "foo=bar". If you boot an old kernel that does not know about "noxsaves" with "noxsaves" on the command line, it will interpret the argument as "noxsave", which is not what you want at all. This makes the "noxsave" handler only return success when it finds an *exact* match. [ tglx: We really need to make __setup() more robust. ] Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Dave Hansen <dave@xxxxxxxx> Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx> Cc: x86@xxxxxxxxxx Link: http://lkml.kernel.org/r/20141111220133.FE053984@xxxxxxxxxxxxxxxxxx Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/cpu/common.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -146,6 +146,8 @@ EXPORT_PER_CPU_SYMBOL_GPL(gdt_page); static int __init x86_xsave_setup(char *s) { + if (strlen(s)) + return 0; setup_clear_cpu_cap(X86_FEATURE_XSAVE); setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT); setup_clear_cpu_cap(X86_FEATURE_XSAVES); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html