From: Rusty Russell Don't abuse CONFIG_DEBUG_KERNEL, add CONFIG_DEBUG_PARAVIRT. Signed-off-by: Rusty Russell Cc: Jeremy Fitzhardinge Cc: Chris Wright Cc: Zachary Amsden Cc: Andi Kleen Signed-off-by: Andrew Morton --- arch/i386/Kconfig.debug | 10 ++++++++++ arch/i386/kernel/alternative.c | 2 +- 2 files changed, 11 insertions(+), 1 deletion(-) diff -puN arch/i386/Kconfig.debug~paravirtualization-patch-inline-replacements-for-fix arch/i386/Kconfig.debug --- a/arch/i386/Kconfig.debug~paravirtualization-patch-inline-replacements-for-fix +++ a/arch/i386/Kconfig.debug @@ -85,4 +85,14 @@ config DOUBLEFAULT option saves about 4k and might cause you much additional grey hair. +config DEBUG_PARAVIRT + bool "Enable some paravirtualization debugging" + default y + depends on PARAVIRT && DEBUG_KERNEL + help + Currently deliberately clobbers regs which are allowed to be + clobbered in inlined paravirt hooks, even in native mode. + If turning this off solves a problem, then DISABLE_INTERRUPTS() or + ENABLE_INTERRUPTS() is lying about what registers can be clobbered. + endmenu diff -puN arch/i386/kernel/alternative.c~paravirtualization-patch-inline-replacements-for-fix arch/i386/kernel/alternative.c --- a/arch/i386/kernel/alternative.c~paravirtualization-patch-inline-replacements-for-fix +++ a/arch/i386/kernel/alternative.c @@ -359,7 +359,7 @@ void apply_paravirt(struct paravirt_patc used = paravirt_ops.patch(p->instrtype, p->clobbers, p->instr, p->len); -#ifdef CONFIG_DEBUG_KERNEL +#ifdef CONFIG_DEBUG_PARAVIRT /* Deliberately clobber regs using "not %reg" to find bugs. */ for (i = 0; i < 3; i++) { if (p->len - used >= 2 && (p->clobbers & (1 << i))) { _