4.9-stable review patch.  If anyone has any objections, please let me know.


From: Chunyan Zhang <zhang.l...@gmail.com>

[ Upstream commit 36b0cb84ee858f02c256d26f0cb4229c78e3399e ]

An additional 'ip' will be pushed to the stack, for restoring the
DACR later, if CONFIG_CPU_SW_DOMAIN_PAN defined.

However, the fixup still get the err_ptr by add #8*4 to sp, which
results in the fact that the code area pointed by the LR will be
overwritten, or the kernel will crash if CONFIG_DEBUG_RODATA is enabled.

This patch fixes the stack mismatch.

Fixes: a5e090acbf54 ("ARM: software-based priviledged-no-access support")
Signed-off-by: Lvqiang Huang <lvqiang.hu...@spreadtrum.com>
Signed-off-by: Chunyan Zhang <zhang.l...@gmail.com>
Signed-off-by: Russell King <rmk+ker...@armlinux.org.uk>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
 arch/arm/lib/csumpartialcopyuser.S |    4 ++++
 1 file changed, 4 insertions(+)

--- a/arch/arm/lib/csumpartialcopyuser.S
+++ b/arch/arm/lib/csumpartialcopyuser.S
@@ -85,7 +85,11 @@
                .pushsection .text.fixup,"ax"
                .align  4
 9001:          mov     r4, #-EFAULT
+               ldr     r5, [sp, #9*4]          @ *err_ptr
                ldr     r5, [sp, #8*4]          @ *err_ptr
                str     r4, [r5]
                ldmia   sp, {r1, r2}            @ retrieve dst, len
                add     r2, r2, r1

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