x86/entry/32: Fix IRET exception

commit 40ad2199580e248dce2a2ebb722854180c334b9e upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 019dbac6fe9d436abc140b0e0c34e9a02d955985..f4335ac9692ff612e50761e8978272004dfc0d16 100644 (file)
--- 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