[12/21] x86/fpu: Do not leak fpstate pointer on fork

Message ID	20211013145322.817101108@linutronix.de (mailing list archive)
State	New, archived
Headers	show Return-Path: <kvm-owner@kernel.org> Message-ID: <20211013145322.817101108@linutronix.de> From: Thomas Gleixner <tglx@linutronix.de> To: LKML <linux-kernel@vger.kernel.org> Cc: x86@kernel.org, "Chang S. Bae" <chang.seok.bae@intel.com>, Dave Hansen <dave.hansen@linux.intel.com>, Arjan van de Ven <arjan@linux.intel.com>, kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com> Subject: [patch 12/21] x86/fpu: Do not leak fpstate pointer on fork References: <20211013142847.120153383@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Date: Wed, 13 Oct 2021 16:55:43 +0200 (CEST) Precedence: bulk
Series	x86/fpu: Move register state into a container struct (part 2) \| expand [00/21] x86/fpu: Move register state into a container struct (part 2) [01/21] x86/fpu: Provide struct fpstate [02/21] x86/fpu: Convert fpstate_init() to struct fpstate [03/21] x86/fpu: Convert restore_fpregs_from_fpstate() to struct fpstate [04/21] x86/fpu: Replace KVMs xstate component clearing [05/21] x86/KVM: Convert to fpstate [06/21] x86/fpu: Convert tracing to fpstate [07/21] x86/fpu/regset: Convert to fpstate [08/21] x86/fpu/signal: Convert to fpstate [09/21] x86/fpu/core: Convert to fpstate [10/21] x86/math-emu: Convert to fpstate [11/21] x86/fpu: Remove fpu::state [12/21] x86/fpu: Do not leak fpstate pointer on fork [13/21] x86/process: Move arch_thread_struct_whitelist() out of line [14/21] x86/fpu: Add size and mask information to fpstate [15/21] x86/fpu: Use fpstate::size [16/21] x86/fpu/xstate: Use fpstate for os_xsave() [17/21] x86/fpu/xstate: Use fpstate for xsave_to_user_sigframe() [18/21] x86/fpu: Use fpstate in fpu_copy_kvm_uabi_to_fpstate() [19/21] x86/fpu: Use fpstate in __copy_xstate_to_uabi_buf() [20/21] x86/fpu/xstate: Use fpstate for copy_uabi_to_xstate() [21/21] x86/fpu/signal: Use fpstate for size and features

Message ID

20211013145322.817101108@linutronix.de (mailing list archive)

State

New, archived

Headers

Message-ID: <20211013145322.817101108@linutronix.de>
From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, "Chang S. Bae" <chang.seok.bae@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Arjan van de Ven <arjan@linux.intel.com>,
        kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Subject: [patch 12/21] x86/fpu: Do not leak fpstate pointer on fork
References: <20211013142847.120153383@linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Date: Wed, 13 Oct 2021 16:55:43 +0200 (CEST)
Precedence: bulk

Series

x86/fpu: Move register state into a container struct (part 2) | expand

Commit Message

Thomas Gleixner Oct. 13, 2021, 2:55 p.m. UTC

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 parents
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 <tglx@linutronix.de>
---
 arch/x86/kernel/process.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -87,6 +87,8 @@  int arch_dup_task_struct(struct task_str
 #ifdef CONFIG_VM86
 	dst->thread.vm86 = NULL;
 #endif
+	/* Drop the copied pointer to current's fpstate */
+	dst->thread.fpu.fpstate = NULL;
 	return 0;
 }

[12/21] x86/fpu: Do not leak fpstate pointer on fork

Commit Message

Patch