From 6db83cea1c975b9a102e17def7d2795814e1ae2b Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Fri, 27 Sep 2013 09:04:41 +0100 Subject: [PATCH] arm64: fix possible invalid FPSIMD initialization state If context switching happens during executing fpsimd_flush_thread(), stale value in FPSIMD registers will be saved into current thread's fpsimd_state by fpsimd_thread_switch(). That may cause invalid initialization state for the new process, so disable preemption when executing fpsimd_flush_thread(). Signed-off-by: Jiang Liu Cc: Jiang Liu Signed-off-by: Catalin Marinas --- arch/arm64/kernel/fpsimd.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 1f2e4d5a5c0f..bb785d23dbde 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -80,8 +80,10 @@ void fpsimd_thread_switch(struct task_struct *next) void fpsimd_flush_thread(void) { + preempt_disable(); memset(¤t->thread.fpsimd_state, 0, sizeof(struct fpsimd_state)); fpsimd_load_state(¤t->thread.fpsimd_state); + preempt_enable(); } #ifdef CONFIG_KERNEL_MODE_NEON -- 2.39.2