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Date: Mon, 1 Jan 2018 15:38:53 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Andy Lutomirski <luto@...nel.org>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Borislav Petkov <bp@...en8.de>,
Brian Gerst <brgerst@...il.com>,
Dave Hansen <dave.hansen@...el.com>,
David Laight <David.Laight@...lab.com>,
Kees Cook <keescook@...omium.org>,
"Kirill A. Shutemov" <kirill@...temov.name>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Peter Zijlstra <peterz@...radead.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...nel.org>
Subject: [PATCH 4.14 142/146] x86/espfix/64: Fix espfix double-fault handling on 5-level systems
4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andy Lutomirski <luto@...nel.org>
commit c739f930be1dd5fd949030e3475a884fe06dae9b upstream.
Using PGDIR_SHIFT to identify espfix64 addresses on 5-level systems
was wrong, and it resulted in panics due to unhandled double faults.
Use P4D_SHIFT instead, which is correct on 4-level and 5-level
machines.
This fixes a panic when running x86 selftests on 5-level machines.
Signed-off-by: Andy Lutomirski <luto@...nel.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: David Laight <David.Laight@...lab.com>
Cc: Kees Cook <keescook@...omium.org>
Cc: Kirill A. Shutemov <kirill@...temov.name>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Fixes: 1d33b219563f ("x86/espfix: Add support for 5-level paging")
Link: http://lkml.kernel.org/r/24c898b4f44fdf8c22d93703850fb384ef87cfdc.1513035461.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/x86/kernel/traps.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -361,7 +361,7 @@ dotraplinkage void do_double_fault(struc
*
* No need for ist_enter here because we don't use RCU.
*/
- if (((long)regs->sp >> PGDIR_SHIFT) == ESPFIX_PGD_ENTRY &&
+ if (((long)regs->sp >> P4D_SHIFT) == ESPFIX_PGD_ENTRY &&
regs->cs == __KERNEL_CS &&
regs->ip == (unsigned long)native_irq_return_iret)
{
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