2018-12-14 09:55:05 +00:00
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Tue, 11 Dec 2018 15:10:33 +0100
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Subject: [PATCH] x86/fpu: Disable preemption around local_bh_disable()
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2019-02-27 18:51:46 +00:00
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.25-rt16.tar.xz
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2018-12-14 09:55:05 +00:00
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__fpu__restore_sig() restores the content of the FPU state in the CPUs
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and in order to avoid concurency it disbles BH. On !RT it also disables
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preemption but on RT we can get preempted in BH.
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Add preempt_disable() while the FPU state is restored.
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Cc: stable-rt@vger.kernel.org
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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arch/x86/kernel/fpu/signal.c | 2 ++
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1 file changed, 2 insertions(+)
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--- a/arch/x86/kernel/fpu/signal.c
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+++ b/arch/x86/kernel/fpu/signal.c
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@@ -344,10 +344,12 @@ static int __fpu__restore_sig(void __use
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sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
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}
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+ preempt_disable();
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local_bh_disable();
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fpu->initialized = 1;
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fpu__restore(fpu);
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local_bh_enable();
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+ preempt_enable();
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return err;
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} else {
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