From 87cdb98affe54b6f390f4622b254569b90820817 Mon Sep 17 00:00:00 2001 From: Ingo Molnar <mingo@kernel.org> Date: Fri, 3 Apr 2015 11:06:43 +0200 Subject: [PATCH] x86/fpu: Add debugging check to fpu__save() Document the function a bit more and add debugging check that we are only running this with the current task. Reviewed-by: Borislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/kernel/i387.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index ac47278cde71..66f1053ae2cd 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -119,9 +119,13 @@ EXPORT_SYMBOL(__kernel_fpu_end); /* * Save the FPU state (initialize it if necessary): + * + * This only ever gets called for the current task. */ void fpu__save(struct task_struct *tsk) { + WARN_ON(tsk != current); + preempt_disable(); if (__thread_has_fpu(tsk)) { if (use_eager_fpu()) { -- GitLab