[PATCH 3.10 122/129] arm64: fix possible invalid FPSIMD initialization state
From: Greg Kroah-Hartman
Date: Mon Jan 06 2014 - 18:02:59 EST
3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jiang Liu <jiang.liu@xxxxxxxxxx>
commit 6db83cea1c975b9a102e17def7d2795814e1ae2b upstream.
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 <jiang.liu@xxxxxxxxxx>
Cc: Jiang Liu <liuj97@xxxxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/fpsimd.c | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -79,8 +79,10 @@ void fpsimd_thread_switch(struct task_st
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();
}
/*
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/