We are not supposed to call kernel_fpu_disable() if we have not
previously enabled it.
Also use kernel_fpu_disable()/enable() in the __kernel_fpu_begin/end()
primitives, instead of writing to in_kernel_fpu directly,
so that we get the debugging checks.
Reviewed-by: Borislav Petkov <b...@alien8.de>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: Fenghua Yu <fenghua...@intel.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
arch/x86/kernel/fpu/core.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 587e4ab46f59..bcf705751d02 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -17,6 +17,7 @@ static void kernel_fpu_disable(void)
static void kernel_fpu_enable(void)
{
+ WARN_ON_ONCE(!this_cpu_read(in_kernel_fpu));
this_cpu_write(in_kernel_fpu, false);
}
@@ -77,7 +78,7 @@ void __kernel_fpu_begin(void)
{
struct task_struct *me = current;
- this_cpu_write(in_kernel_fpu, true);
+ kernel_fpu_disable();
if (__thread_has_fpu(me)) {
__save_init_fpu(me);
@@ -100,7 +101,7 @@ void __kernel_fpu_end(void)
stts();
}
- this_cpu_write(in_kernel_fpu, false);
+ kernel_fpu_enable();
}
EXPORT_SYMBOL(__kernel_fpu_end);
--
2.1.0
--
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