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, 27 insertions, 0 deletions

diff --git a/drivers/pinctrl/intel/Makefile b/drivers/pinctrl/intel/Makefile
new file mode 100644
index 000000000..d0d868c9a
--- /dev/null
+++ b/drivers/pinctrl/intel/Makefile
@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0
+# Intel pin control drivers
+
+obj-$(CONFIG_PINCTRL_BAYTRAIL)		+= pinctrl-baytrail.o
+obj-$(CONFIG_PINCTRL_CHERRYVIEW)	+= pinctrl-cherryview.o
+obj-$(CONFIG_PINCTRL_LYNXPOINT)		+= pinctrl-lynxpoint.o
+obj-$(CONFIG_PINCTRL_TANGIER)		+= pinctrl-tangier.o
+obj-$(CONFIG_PINCTRL_MERRIFIELD)	+= pinctrl-merrifield.o
+obj-$(CONFIG_PINCTRL_MOOREFIELD)	+= pinctrl-moorefield.o
+obj-$(CONFIG_PINCTRL_INTEL)		+= pinctrl-intel.o
+obj-$(CONFIG_PINCTRL_INTEL_PLATFORM)	+= pinctrl-intel-platform.o
+obj-$(CONFIG_PINCTRL_ALDERLAKE)		+= pinctrl-alderlake.o
+obj-$(CONFIG_PINCTRL_BROXTON)		+= pinctrl-broxton.o
+obj-$(CONFIG_PINCTRL_CANNONLAKE)	+= pinctrl-cannonlake.o
+obj-$(CONFIG_PINCTRL_CEDARFORK)		+= pinctrl-cedarfork.o
+obj-$(CONFIG_PINCTRL_DENVERTON)		+= pinctrl-denverton.o
+obj-$(CONFIG_PINCTRL_ELKHARTLAKE)	+= pinctrl-elkhartlake.o
+obj-$(CONFIG_PINCTRL_EMMITSBURG)	+= pinctrl-emmitsburg.o
+obj-$(CONFIG_PINCTRL_GEMINILAKE)	+= pinctrl-geminilake.o
+obj-$(CONFIG_PINCTRL_ICELAKE)		+= pinctrl-icelake.o
+obj-$(CONFIG_PINCTRL_JASPERLAKE)	+= pinctrl-jasperlake.o
+obj-$(CONFIG_PINCTRL_LAKEFIELD)		+= pinctrl-lakefield.o
+obj-$(CONFIG_PINCTRL_LEWISBURG)		+= pinctrl-lewisburg.o
+obj-$(CONFIG_PINCTRL_METEORLAKE)	+= pinctrl-meteorlake.o
+obj-$(CONFIG_PINCTRL_METEORPOINT)	+= pinctrl-meteorpoint.o
+obj-$(CONFIG_PINCTRL_SUNRISEPOINT)	+= pinctrl-sunrisepoint.o
+obj-$(CONFIG_PINCTRL_TIGERLAKE)		+= pinctrl-tigerlake.o