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, 48 insertions, 0 deletions

diff --git a/drivers/phy/intel/Kconfig b/drivers/phy/intel/Kconfig
new file mode 100644
index 000000000..ac42bb2fb
--- /dev/null
+++ b/drivers/phy/intel/Kconfig
@@ -0,0 +1,48 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Phy drivers for Intel platforms
+#
+config PHY_INTEL_KEEMBAY_EMMC
+	tristate "Intel Keem Bay EMMC PHY driver"
+	depends on ARCH_KEEMBAY || COMPILE_TEST
+	depends on HAS_IOMEM
+	select GENERIC_PHY
+	select REGMAP_MMIO
+	help
+	  Choose this option if you have an Intel Keem Bay SoC.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called phy-keembay-emmc.ko.
+
+config PHY_INTEL_KEEMBAY_USB
+	tristate "Intel Keem Bay USB PHY driver"
+	depends on ARCH_KEEMBAY || COMPILE_TEST
+	depends on HAS_IOMEM
+	select GENERIC_PHY
+	select REGMAP_MMIO
+	help
+	  Choose this option if you have an Intel Keem Bay SoC.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called phy-keembay-usb.ko.
+
+config PHY_INTEL_LGM_COMBO
+	bool "Intel Lightning Mountain ComboPHY driver"
+	depends on X86 || COMPILE_TEST
+	depends on OF && HAS_IOMEM
+	select MFD_SYSCON
+	select GENERIC_PHY
+	select REGMAP
+	help
+	  Enable this to support Intel ComboPhy.
+
+	  This driver configures ComboPhy subsystem on Intel gateway
+	  chipsets which provides PHYs for various controllers, EMAC,
+	  SATA and PCIe.
+
+config PHY_INTEL_LGM_EMMC
+	tristate "Intel Lightning Mountain EMMC PHY driver"
+	depends on X86 || COMPILE_TEST
+	select GENERIC_PHY
+	help
+	  Enable this to support the Intel EMMC PHY