From f0cbc8b3cdf7d1c724155cd9cecffe329bb96119 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 13 Oct 2021 16:55:43 +0200 Subject: [PATCH] x86/fpu: Do not leak fpstate pointer on fork If fork fails early then the copied task struct would carry the fpstate pointer of the parent task. Not a problem right now, but later when dynamically allocated buffers are available, keeping the pointer might result in freeing the parent's buffer. Set it to NULL which prevents that. If fork reaches clone_thread(), the pointer will be correctly set to the new task context. Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20211013145322.817101108@linutronix.de --- arch/x86/kernel/process.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 5cd82082353e..c74c7e889e9d 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -87,6 +87,8 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) #ifdef CONFIG_VM86 dst->thread.vm86 = NULL; #endif + /* Drop the copied pointer to current's fpstate */ + dst->thread.fpu.fpstate = NULL; return 0; } -- 2.11.0