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, 121 insertions, 0 deletions

diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
new file mode 100644
index 000000000..66944a4f4
--- /dev/null
+++ b/tools/perf/tests/Build
@@ -0,0 +1,121 @@
+# SPDX-License-Identifier: GPL-2.0
+
+perf-test-y += builtin-test.o
+perf-test-y += tests-scripts.o
+perf-test-y += parse-events.o
+perf-test-y += uncore-event-sorting.o
+perf-test-y += dso-data.o
+perf-test-y += vmlinux-kallsyms.o
+perf-test-y += openat-syscall.o
+perf-test-y += openat-syscall-all-cpus.o
+perf-test-$(CONFIG_LIBTRACEEVENT) += openat-syscall-tp-fields.o
+perf-test-y += mmap-basic.o
+perf-test-y += perf-record.o
+perf-test-y += evsel-roundtrip-name.o
+perf-test-$(CONFIG_LIBTRACEEVENT) += evsel-tp-sched.o
+perf-test-y += fdarray.o
+perf-test-y += pmu.o
+perf-test-y += pmu-events.o
+perf-test-y += hists_common.o
+perf-test-y += hists_link.o
+perf-test-y += hists_filter.o
+perf-test-y += hists_output.o
+perf-test-y += hists_cumulate.o
+perf-test-y += bp_signal.o
+perf-test-y += bp_signal_overflow.o
+perf-test-y += bp_account.o
+perf-test-y += wp.o
+perf-test-y += task-exit.o
+perf-test-y += sw-clock.o
+perf-test-y += mmap-thread-lookup.o
+perf-test-y += thread-maps-share.o
+perf-test-$(CONFIG_LIBTRACEEVENT) += switch-tracking.o
+perf-test-y += keep-tracking.o
+perf-test-y += code-reading.o
+perf-test-y += sample-parsing.o
+perf-test-y += parse-no-sample-id-all.o
+perf-test-y += kmod-path.o
+perf-test-y += thread-map.o
+perf-test-y += topology.o
+perf-test-y += mem.o
+perf-test-y += cpumap.o
+perf-test-y += stat.o
+perf-test-y += event_update.o
+perf-test-y += event-times.o
+perf-test-y += expr.o
+perf-test-y += backward-ring-buffer.o
+perf-test-y += sdt.o
+perf-test-y += is_printable_array.o
+perf-test-y += bitmap.o
+perf-test-y += perf-hooks.o
+perf-test-y += unit_number__scnprintf.o
+perf-test-y += mem2node.o
+perf-test-y += maps.o
+perf-test-y += time-utils-test.o
+perf-test-y += genelf.o
+perf-test-y += api-io.o
+perf-test-y += demangle-java-test.o
+perf-test-y += demangle-ocaml-test.o
+perf-test-y += demangle-rust-v0-test.o
+perf-test-y += pfm.o
+perf-test-y += parse-metric.o
+perf-test-y += pe-file-parsing.o
+perf-test-y += expand-cgroup.o
+perf-test-y += perf-time-to-tsc.o
+perf-test-y += dlfilter-test.o
+perf-test-y += sigtrap.o
+perf-test-y += event_groups.o
+perf-test-y += symbols.o
+perf-test-y += util.o
+perf-test-y += hwmon_pmu.o
+perf-test-y += tool_pmu.o
+perf-test-y += subcmd-help.o
+perf-test-y += kallsyms-split.o
+
+ifeq ($(SRCARCH),$(filter $(SRCARCH),x86 arm arm64 powerpc))
+perf-test-$(CONFIG_DWARF_UNWIND) += dwarf-unwind.o
+endif
+
+CFLAGS_dwarf-unwind.o += -fno-optimize-sibling-calls
+
+perf-test-y += workloads/
+
+ifdef SHELLCHECK
+  SHELL_TESTS := $(shell find tests/shell -executable -type f -name '*.sh')
+  SHELL_TEST_LOGS := $(SHELL_TESTS:tests/shell/%=shell/%.shellcheck_log)
+else
+  SHELL_TESTS :=
+  SHELL_TEST_LOGS :=
+endif
+
+$(OUTPUT)%.shellcheck_log: %
+	$(call rule_mkdir)
+	$(Q)$(call echo-cmd,test)$(SHELLCHECK) "$<" > $@ || (cat $@ && rm $@ && false)
+
+perf-test-y += $(SHELL_TEST_LOGS)
+
+ifdef MYPY
+  PY_TESTS := $(shell find tests/shell -type f -name '*.py')
+  MYPY_TEST_LOGS := $(PY_TESTS:tests/shell/%=shell/%.mypy_log)
+else
+  MYPY_TEST_LOGS :=
+endif
+
+$(OUTPUT)%.mypy_log: %
+	$(call rule_mkdir)
+	$(Q)$(call echo-cmd,test)mypy "$<" > $@ || (cat $@ && rm $@ && false)
+
+perf-test-y += $(MYPY_TEST_LOGS)
+
+ifdef PYLINT
+  PY_TESTS := $(shell find tests/shell -type f -name '*.py')
+  PYLINT_TEST_LOGS := $(PY_TESTS:tests/shell/%=shell/%.pylint_log)
+else
+  PYLINT_TEST_LOGS :=
+endif
+
+$(OUTPUT)%.pylint_log: %
+	$(call rule_mkdir)
+	$(Q)$(call echo-cmd,test)pylint "$<" > $@ || (cat $@ && rm $@ && false)
+
+perf-test-y += $(PYLINT_TEST_LOGS)