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, 41 insertions, 0 deletions

diff --git a/drivers/input/mouse/Makefile b/drivers/input/mouse/Makefile
new file mode 100644
index 000000000..ed40f1416
--- /dev/null
+++ b/drivers/input/mouse/Makefile
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the mouse drivers.
+#
+
+# Each configuration option enables a list of files.
+
+obj-$(CONFIG_MOUSE_AMIGA)		+= amimouse.o
+obj-$(CONFIG_MOUSE_APPLETOUCH)		+= appletouch.o
+obj-$(CONFIG_MOUSE_ATARI)		+= atarimouse.o
+obj-$(CONFIG_MOUSE_BCM5974)		+= bcm5974.o
+obj-$(CONFIG_MOUSE_CYAPA)		+= cyapatp.o
+obj-$(CONFIG_MOUSE_ELAN_I2C)		+= elan_i2c.o
+obj-$(CONFIG_MOUSE_GPIO)		+= gpio_mouse.o
+obj-$(CONFIG_MOUSE_MAPLE)		+= maplemouse.o
+obj-$(CONFIG_MOUSE_PS2)			+= psmouse.o
+obj-$(CONFIG_MOUSE_RISCPC)		+= rpcmouse.o
+obj-$(CONFIG_MOUSE_SERIAL)		+= sermouse.o
+obj-$(CONFIG_MOUSE_SYNAPTICS_I2C)	+= synaptics_i2c.o
+obj-$(CONFIG_MOUSE_SYNAPTICS_USB)	+= synaptics_usb.o
+obj-$(CONFIG_MOUSE_VSXXXAA)		+= vsxxxaa.o
+
+cyapatp-objs := cyapa.o cyapa_gen3.o cyapa_gen5.o cyapa_gen6.o
+psmouse-objs := psmouse-base.o synaptics.o focaltech.o
+
+psmouse-$(CONFIG_MOUSE_PS2_ALPS)	+= alps.o
+psmouse-$(CONFIG_MOUSE_PS2_BYD)		+= byd.o
+psmouse-$(CONFIG_MOUSE_PS2_ELANTECH)	+= elantech.o
+psmouse-$(CONFIG_MOUSE_PS2_LOGIPS2PP)	+= logips2pp.o
+psmouse-$(CONFIG_MOUSE_PS2_LIFEBOOK)	+= lifebook.o
+psmouse-$(CONFIG_MOUSE_PS2_SENTELIC)	+= sentelic.o
+psmouse-$(CONFIG_MOUSE_PS2_TRACKPOINT)	+= trackpoint.o
+psmouse-$(CONFIG_MOUSE_PS2_TOUCHKIT)	+= touchkit_ps2.o
+psmouse-$(CONFIG_MOUSE_PS2_CYPRESS)	+= cypress_ps2.o
+psmouse-$(CONFIG_MOUSE_PS2_VMMOUSE)	+= vmmouse.o
+
+psmouse-$(CONFIG_MOUSE_PS2_SMBUS)	+= psmouse-smbus.o
+
+elan_i2c-objs := elan_i2c_core.o
+elan_i2c-$(CONFIG_MOUSE_ELAN_I2C_I2C)	+= elan_i2c_i2c.o
+elan_i2c-$(CONFIG_MOUSE_ELAN_I2C_SMBUS)	+= elan_i2c_smbus.o