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, 33 insertions, 0 deletions

diff --git a/drivers/input/serio/Makefile b/drivers/input/serio/Makefile
new file mode 100644
index 000000000..7f5137dc0
--- /dev/null
+++ b/drivers/input/serio/Makefile
@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the input core drivers.
+#
+
+# Each configuration option enables a list of files.
+
+obj-$(CONFIG_SERIO)		+= serio.o
+obj-$(CONFIG_SERIO_I8042)	+= i8042.o
+obj-$(CONFIG_SERIO_PARKBD)	+= parkbd.o
+obj-$(CONFIG_SERIO_SERPORT)	+= serport.o
+obj-$(CONFIG_SERIO_RPCKBD)	+= rpckbd.o
+obj-$(CONFIG_SERIO_SA1111)	+= sa1111ps2.o
+obj-$(CONFIG_SERIO_AMBAKMI)	+= ambakmi.o
+obj-$(CONFIG_SERIO_Q40KBD)	+= q40kbd.o
+obj-$(CONFIG_SERIO_GSCPS2)	+= gscps2.o
+obj-$(CONFIG_HP_SDC)		+= hp_sdc.o
+obj-$(CONFIG_HIL_MLC)		+= hp_sdc_mlc.o hil_mlc.o
+obj-$(CONFIG_SERIO_PCIPS2)	+= pcips2.o
+obj-$(CONFIG_SERIO_PS2MULT)	+= ps2mult.o
+obj-$(CONFIG_SERIO_MACEPS2)	+= maceps2.o
+obj-$(CONFIG_SERIO_SGI_IOC3)	+= ioc3kbd.o
+obj-$(CONFIG_SERIO_LIBPS2)	+= libps2.o
+obj-$(CONFIG_SERIO_RAW)		+= serio_raw.o
+obj-$(CONFIG_SERIO_AMS_DELTA)	+= ams_delta_serio.o
+obj-$(CONFIG_SERIO_ALTERA_PS2)	+= altera_ps2.o
+obj-$(CONFIG_SERIO_ARC_PS2)	+= arc_ps2.o
+obj-$(CONFIG_SERIO_APBPS2)	+= apbps2.o
+obj-$(CONFIG_SERIO_OLPC_APSP)	+= olpc_apsp.o
+obj-$(CONFIG_HYPERV_KEYBOARD)	+= hyperv-keyboard.o
+obj-$(CONFIG_SERIO_SUN4I_PS2)	+= sun4i-ps2.o
+obj-$(CONFIG_SERIO_GPIO_PS2)	+= ps2-gpio.o
+obj-$(CONFIG_USERIO)		+= userio.o