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Subject[tip: x86/urgent] x86/entry/32: Fix IRET exception
The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: 40ad2199580e248dce2a2ebb722854180c334b9e
Gitweb: https://git.kernel.org/tip/40ad2199580e248dce2a2ebb722854180c334b9e
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Wed, 20 Nov 2019 13:05:06 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Thu, 21 Nov 2019 19:37:43 +01:00

x86/entry/32: Fix IRET exception

As reported by Lai, the commit 3c88c692c287 ("x86/stackframe/32:
Provide consistent pt_regs") wrecked the IRET EXTABLE entry by making
.Lirq_return not point at IRET.

Fix this by placing IRET_FRAME in RESTORE_REGS, to mirror how
FIXUP_FRAME is part of SAVE_ALL.

Fixes: 3c88c692c287 ("x86/stackframe/32: Provide consistent pt_regs")
Reported-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: stable@kernel.org
---
arch/x86/entry/entry_32.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 019dbac..f4335ac 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -357,6 +357,7 @@
2: popl %es
3: popl %fs
POP_GS \pop
+ IRET_FRAME
.pushsection .fixup, "ax"
4: movl $0, (%esp)
jmp 1b
@@ -1075,7 +1076,6 @@ restore_all:
/* Restore user state */
RESTORE_REGS pop=4 # skip orig_eax/error_code
.Lirq_return:
- IRET_FRAME
/*
* ARCH_HAS_MEMBARRIER_SYNC_CORE rely on IRET core serialization
* when returning from IPI handler and when returning from
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