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| author | Oleg Nesterov <oleg@redhat.com> | 2015-03-13 09:53:10 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-03-13 12:44:29 +0100 |
| commit | f4c3686386393c120710dd34df2a74183ab805fd (patch) | |
| tree | 41bea4fc661250f749387f635691b6c094512020 | |
| parent | a7c80ebcac3068b1c3cb27d538d29558c30010c8 (diff) | |
| download | linux-f4c3686386393c120710dd34df2a74183ab805fd.tar.gz linux-f4c3686386393c120710dd34df2a74183ab805fd.tar.bz2 linux-f4c3686386393c120710dd34df2a74183ab805fd.zip | |
x86/fpu: Drop_fpu() should not assume that tsk equals current
drop_fpu() does clear_used_math() and usually this is correct
because tsk == current.
However switch_fpu_finish()->restore_fpu_checking() is called before
__switch_to() updates the "current_task" variable. If it fails,
we will wrongly clear the PF_USED_MATH flag of the previous task.
So use clear_stopped_child_used_math() instead.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Riikonen <priikone@iki.fi>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150309171041.GB11388@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/include/asm/fpu-internal.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index 0dbc08282291..72ba21a8b5fc 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -370,7 +370,7 @@ static inline void drop_fpu(struct task_struct *tsk) preempt_disable(); tsk->thread.fpu_counter = 0; __drop_fpu(tsk); - clear_used_math(); + clear_stopped_child_used_math(tsk); preempt_enable(); } |