From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Matthew Whitehead <tedheadster@gmail.com>,
Andy Lutomirski <luto@kernel.org>
Subject: [PATCH 4.4 04/13] x86/traps: Ignore high word of regs->cs in early_fixup_exception()
Date: Wed, 7 Dec 2016 08:07:43 +0100 [thread overview]
Message-ID: <20161207070716.507248027@linuxfoundation.org> (raw)
In-Reply-To: <20161207070716.317145973@linuxfoundation.org>
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andy Lutomirski <luto@kernel.org>
commit fc0e81b2bea0ebceb71889b61d2240856141c9ee upstream.
On the 80486 DX, it seems that some exceptions may leave garbage in
the high bits of CS. This causes sporadic failures in which
early_fixup_exception() refuses to fix up an exception.
As far as I can tell, this has been buggy for a long time, but the
problem seems to have been exacerbated by commits:
1e02ce4cccdc ("x86: Store a per-cpu shadow copy of CR4")
e1bfc11c5a6f ("x86/init: Fix cr4_init_shadow() on CR4-less machines")
This appears to have broken for as long as we've had early
exception handling.
[ This backport should apply to kernels from 3.4 - 4.5. ]
Fixes: 4c5023a3fa2e ("x86-32: Handle exception table entries during early boot")
Cc: H. Peter Anvin <hpa@zytor.com>
Reported-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/head_32.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -571,7 +571,7 @@ early_idt_handler_common:
movl %eax,%ds
movl %eax,%es
- cmpl $(__KERNEL_CS),32(%esp)
+ cmpw $(__KERNEL_CS),32(%esp)
jne 10f
leal 28(%esp),%eax # Pointer to %eip
next prev parent reply other threads:[~2016-12-07 7:08 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20161207070805epcas3p1487b13063215635759cae58441ad906a@epcas3p1.samsung.com>
2016-12-07 7:07 ` [PATCH 4.4 00/13] 4.4.37-stable review Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 01/13] ARC: Dont use "+l" inline asm constraint Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 02/13] zram: fix unbalanced idr management at hot removal Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 03/13] kasan: update kasan_global for gcc 7 Greg Kroah-Hartman
2016-12-07 7:07 ` Greg Kroah-Hartman [this message]
2016-12-07 7:07 ` [PATCH 4.4 05/13] ALSA: pcm : Call kill_fasync() in stream lock Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 06/13] rcu: Fix soft lockup for rcu_nocb_kthread Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 07/13] PCI: Export pcie_find_root_port Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 09/13] mwifiex: printk() overflow with 32-byte SSIDs Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 10/13] pwm: Fix device reference leak Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 11/13] arm64: cpufeature: Schedule enable() calls instead of calling them via IPI Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 12/13] arm64: mm: Set PSTATE.PAN from the cpu_enable_pan() call Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 13/13] arm64: suspend: Reconfigure PSTATE after resume from idle Greg Kroah-Hartman
2016-12-07 16:07 ` [PATCH 4.4 00/13] 4.4.37-stable review Guenter Roeck
2016-12-07 18:17 ` Shuah Khan
[not found] ` <5847f96a.45f6c20a.fab5.7b38@mx.google.com>
[not found] ` <m2inqvekqu.fsf@baylibre.com>
2016-12-08 16:25 ` Greg Kroah-Hartman
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