From 08a744c6bfded3d5fa66f94263f81773226113d1 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 6 Feb 2015 15:02:00 -0500 Subject: [PATCH] x86/fpu: Change math_error() to use unlazy_fpu(), kill (now) unused save_init_fpu() math_error() calls save_init_fpu() after conditional_sti(), this means that the caller can be preempted. If !use_eager_fpu() we can hit the WARN_ON_ONCE(!__thread_has_fpu(tsk)) and/or save the wrong FPU state. Change math_error() to use unlazy_fpu() and kill save_init_fpu(). Signed-off-by: Oleg Nesterov Signed-off-by: Rik van Riel Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1423252925-14451-4-git-send-email-riel@redhat.com Signed-off-by: Borislav Petkov --- arch/x86/include/asm/fpu-internal.h | 18 ------------------ arch/x86/kernel/traps.c | 2 +- 2 files changed, 1 insertion(+), 19 deletions(-) diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index e97622f57722..02f2e0817918 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -517,24 +517,6 @@ static inline void __save_fpu(struct task_struct *tsk) fpu_fxsave(&tsk->thread.fpu); } -/* - * These disable preemption on their own and are safe - */ -static inline void save_init_fpu(struct task_struct *tsk) -{ - WARN_ON_ONCE(!__thread_has_fpu(tsk)); - - if (use_eager_fpu()) { - __save_fpu(tsk); - return; - } - - preempt_disable(); - __save_init_fpu(tsk); - __thread_fpu_end(tsk); - preempt_enable(); -} - /* * i387 state interaction */ diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 88900e288021..9d889f74e806 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -663,7 +663,7 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr) /* * Save the info for the exception handler and clear the error. */ - save_init_fpu(task); + unlazy_fpu(task); task->thread.trap_nr = trapnr; task->thread.error_code = error_code; info.si_signo = SIGFPE; -- 2.39.5