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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
Date: Wed, 13 Oct 2021 16:55:43 +0200 (CEST)	[thread overview]
Message-ID: <20211013145322.817101108@linutronix.de> (raw)
In-Reply-To: 20211013142847.120153383@linutronix.de

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;
 }
 


  parent reply	other threads:[~2021-10-13 14:55 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-13 14:55 [patch 00/21] x86/fpu: Move register state into a container struct (part 2) Thomas Gleixner
2021-10-13 14:55 ` [patch 01/21] x86/fpu: Provide struct fpstate Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 02/21] x86/fpu: Convert fpstate_init() to " Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 03/21] x86/fpu: Convert restore_fpregs_from_fpstate() " Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 04/21] x86/fpu: Replace KVMs xstate component clearing Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 05/21] x86/KVM: Convert to fpstate Thomas Gleixner
2021-10-13 15:11   ` Paolo Bonzini
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 06/21] x86/fpu: Convert tracing " Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 07/21] x86/fpu/regset: Convert " Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 08/21] x86/fpu/signal: " Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 09/21] x86/fpu/core: " Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 10/21] x86/math-emu: " Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 11/21] x86/fpu: Remove fpu::state Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` Thomas Gleixner [this message]
2021-10-21 15:12   ` [tip: x86/fpu] x86/fpu: Do not leak fpstate pointer on fork tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 13/21] x86/process: Move arch_thread_struct_whitelist() out of line Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 14/21] x86/fpu: Add size and mask information to fpstate Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 15/21] x86/fpu: Use fpstate::size Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 16/21] x86/fpu/xstate: Use fpstate for os_xsave() Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 17/21] x86/fpu/xstate: Use fpstate for xsave_to_user_sigframe() Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 18/21] x86/fpu: Use fpstate in fpu_copy_kvm_uabi_to_fpstate() Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 19/21] x86/fpu: Use fpstate in __copy_xstate_to_uabi_buf() Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 20/21] x86/fpu/xstate: Use fpstate for copy_uabi_to_xstate() Thomas Gleixner
2021-10-21 15:12   ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-10-13 14:55 ` [patch 21/21] x86/fpu/signal: Use fpstate for size and features Thomas Gleixner
2021-10-14 22:51   ` [patch V2 " Thomas Gleixner
2021-10-21 15:12     ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner

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