From 1039bffd6ae9c75b42b7d148d6c1106134107b66 Mon Sep 17 00:00:00 2001 From: Xie Yuanbin Date: Tue, 28 Jul 2026 03:16:42 +0100 Subject: ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults 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 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) Reviewed-by: Linus Walleij Signed-off-by: Qi Xi Signed-off-by: Xie Yuanbin Signed-off-by: Russell King --- tools/perf/scripts/Build | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 tools/perf/scripts/Build (limited to 'tools/perf/scripts/Build') diff --git a/tools/perf/scripts/Build b/tools/perf/scripts/Build new file mode 100644 index 000000000..91229a1fe --- /dev/null +++ b/tools/perf/scripts/Build @@ -0,0 +1,30 @@ +ifeq ($(CONFIG_LIBTRACEEVENT),y) + perf-util-$(CONFIG_LIBPERL) += perl/Perf-Trace-Util/ +endif +perf-util-$(CONFIG_LIBPYTHON) += python/Perf-Trace-Util/ + +ifdef MYPY + PY_TESTS := $(shell find python -type f -name '*.py') + MYPY_TEST_LOGS := $(PY_TESTS:python/%=python/%.mypy_log) +else + MYPY_TEST_LOGS := +endif + +$(OUTPUT)%.mypy_log: % + $(call rule_mkdir) + $(Q)$(call echo-cmd,test)mypy "$<" > $@ || (cat $@ && rm $@ && false) + +perf-y += $(MYPY_TEST_LOGS) + +ifdef PYLINT + PY_TESTS := $(shell find python -type f -name '*.py') + PYLINT_TEST_LOGS := $(PY_TESTS:python/%=python/%.pylint_log) +else + PYLINT_TEST_LOGS := +endif + +$(OUTPUT)%.pylint_log: % + $(call rule_mkdir) + $(Q)$(call echo-cmd,test)pylint "$<" > $@ || (cat $@ && rm $@ && false) + +perf-y += $(PYLINT_TEST_LOGS) -- cgit v1.3.1