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, 25 insertions, 0 deletions

diff --git a/drivers/net/ipa/Makefile b/drivers/net/ipa/Makefile
new file mode 100644
index 000000000..e148ec3c1
--- /dev/null
+++ b/drivers/net/ipa/Makefile
@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Qualcomm IPA driver.
+
+IPA_REG_VERSIONS	:=	3.1 3.5.1 4.2 4.5 4.7 4.9 4.11 5.0 5.5
+
+# Some IPA versions can reuse another set of GSI register definitions.
+GSI_REG_VERSIONS	:=	3.1 3.5.1 4.0 4.5 4.9 4.11 5.0
+
+IPA_DATA_VERSIONS	:=	3.1 3.5.1 4.2 4.5 4.7 4.9 4.11 5.0 5.2 5.5
+
+obj-$(CONFIG_QCOM_IPA)	+=	ipa.o
+
+ipa-y			:=	ipa_main.o ipa_power.o ipa_reg.o ipa_mem.o \
+				ipa_table.o ipa_interrupt.o gsi.o gsi_reg.o \
+				gsi_trans.o ipa_gsi.o ipa_smp2p.o ipa_uc.o \
+				ipa_endpoint.o ipa_cmd.o ipa_modem.o \
+				ipa_resource.o ipa_qmi.o ipa_qmi_msg.o \
+				ipa_sysfs.o
+
+ipa-y			+=	$(IPA_REG_VERSIONS:%=reg/ipa_reg-v%.o)
+
+ipa-y			+=	$(GSI_REG_VERSIONS:%=reg/gsi_reg-v%.o)
+
+ipa-y			+=	$(IPA_DATA_VERSIONS:%=data/ipa_data-v%.o)