4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chunyan Zhang <zhang.lyra@xxxxxxxxx>
[ 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.Huang@xxxxxxxxxxxxxx>
Signed-off-by: Chunyan Zhang <zhang.lyra@xxxxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
+#ifdef CONFIG_CPU_SW_DOMAIN_PAN
+ ldr r5, [sp, #9*4] @ *err_ptr
+#else
ldr r5, [sp, #8*4] @ *err_ptr
+#endif
str r4, [r5]
ldmia sp, {r1, r2} @ retrieve dst, len
add r2, r2, r1