ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faultsgrafted

When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set,
a user fault may trigger show_pte() without any lock.
If another thread in the same process concurrently calls munmap(),
the page table pages may be freed while show_pte() is still traversing
them, causing a use-after-free in show_pte().

If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table
of PMD are freed when show_pte() is running.

Acquire mmap_write_lock() around show_pte() for user faults to fix the
contention.

For user faults, additionally restrict that show_pte() is called only
when the addr is a user-space address (addr < TASK_SIZE). This is because
the lock of tsk->mm only protects the virtual memory of user address space,
furthermore, dumping the page tables of a kernel-space address for user
faults is unnecessary and may have security implications.

Keep everything unchanged for kernel faults, because the kernel is
already in the "oops" state, acquiring a lock may risk a deadlock.

Co-developed-by: Qi Xi <xiqi2@huawei.com>

Fixes: 6d021b724481 ("ARM: dump pgd, pmd and pte states on unhandled data abort faults")
Link: https://lore.kernel.org/20260716014022.2823-1-xieyuanbin1@huawei.com
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Qi Xi <xiqi2@huawei.com>
Signed-off-by: Xie Yuanbin <xieyuanbin1@huawei.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
new file mode 100644
index 000000000..d7aa516bc
--- /dev/null
+++ b/drivers/phy/Makefile
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the phy drivers.
+#
+
+obj-$(CONFIG_PHY_COMMON_PROPS)		+= phy-common-props.o
+obj-$(CONFIG_PHY_COMMON_PROPS_TEST)	+= phy-common-props-test.o
+obj-$(CONFIG_GENERIC_PHY)		+= phy-core.o
+obj-$(CONFIG_GENERIC_PHY_MIPI_DPHY)	+= phy-core-mipi-dphy.o
+obj-$(CONFIG_PHY_AIROHA_PCIE)		+= phy-airoha-pcie.o
+obj-$(CONFIG_PHY_CAN_TRANSCEIVER)	+= phy-can-transceiver.o
+obj-$(CONFIG_PHY_ECONET_PCIE)		+= phy-econet-pcie.o
+obj-$(CONFIG_PHY_EYEQ5_ETH)		+= phy-eyeq5-eth.o
+obj-$(CONFIG_PHY_GOOGLE_USB)		+= phy-google-usb.o
+obj-$(CONFIG_USB_LGM_PHY)		+= phy-lgm-usb.o
+obj-$(CONFIG_PHY_LPC18XX_USB_OTG)	+= phy-lpc18xx-usb-otg.o
+obj-$(CONFIG_PHY_NXP_PTN3222)		+= phy-nxp-ptn3222.o
+obj-$(CONFIG_PHY_NXP_TJA1145)		+= phy-nxp-tja1145.o
+obj-$(CONFIG_PHY_PISTACHIO_USB)		+= phy-pistachio-usb.o
+obj-$(CONFIG_PHY_SNPS_EUSB2)		+= phy-snps-eusb2.o
+obj-$(CONFIG_PHY_XGENE)			+= phy-xgene.o
+
+obj-$(CONFIG_GENERIC_PHY)		+= allwinner/	\
+					   amlogic/	\
+					   apple/	\
+					   axiado/	\
+					   broadcom/	\
+					   cadence/	\
+					   canaan/	\
+					   eswin/	\
+					   freescale/	\
+					   hisilicon/	\
+					   ingenic/	\
+					   intel/	\
+					   lantiq/	\
+					   marvell/	\
+					   mediatek/	\
+					   microchip/	\
+					   motorola/	\
+					   mscc/	\
+					   nuvoton/	\
+					   qualcomm/	\
+					   ralink/	\
+					   realtek/	\
+					   renesas/	\
+					   rockchip/	\
+					   samsung/	\
+					   socionext/	\
+					   sophgo/	\
+					   spacemit/	\
+					   st/		\
+					   starfive/	\
+					   sunplus/	\
+					   tegra/	\
+					   ti/		\
+					   xilinx/