x86/fpu: Change math_error() to use unlazy_fpu(), kill (now) unused save_init_fpu()

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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 <oleg@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1423252925-14451-4-git-send-email-riel@redhat.com
Signed-off-by: Borislav Petkov <bp@suse.de>

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Oleg Nesterov 2015-02-06 15:02:00 -05:00 • committed by Borislav Petkov

parent 1a2a7f4ec8

commit 08a744c6bf

2 changed files with 1 additions and 19 deletions

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18

arch/x86/include/asm/fpu-internal.h

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2

arch/x86/kernel/traps.c

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