From: Jinchao Wang <wangjinchao600@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H . Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
David Hildenbrand <david@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Matthew Wilcox <willy@infradead.org>,
Alan Stern <stern@rowland.harvard.edu>,
Randy Dunlap <rdunlap@infradead.org>,
Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>, Mike Rapoport <rppt@kernel.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-trace-kernel@vger.kernel.org,
linux-perf-users@vger.kernel.org, linux-doc@vger.kernel.org,
Jinchao Wang <wangjinchao600@gmail.com>
Subject: [RFC PATCH v2 12/13] mm/kwatch: add KUnit tests for the watch expression parser
Date: Fri, 17 Jul 2026 09:07:02 -0400 [thread overview]
Message-ID: <20260717130702.1903917-1-wangjinchao600@gmail.com> (raw)
In-Reply-To: <20260717125023.1895892-1-wangjinchao600@gmail.com>
Cover base anchors (stack, argN, absolute address), positive and
negative offsets, dereference chains, and rejection of malformed
expressions (missing offsets, bad argument index, junk offsets).
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
---
mm/kwatch/.kunitconfig | 9 +++
mm/kwatch/Kconfig | 12 ++++
mm/kwatch/Makefile | 1 +
mm/kwatch/deref_test.c | 146 +++++++++++++++++++++++++++++++++++++++++
4 files changed, 168 insertions(+)
create mode 100644 mm/kwatch/.kunitconfig
create mode 100644 mm/kwatch/deref_test.c
diff --git a/mm/kwatch/.kunitconfig b/mm/kwatch/.kunitconfig
new file mode 100644
index 000000000000..7e977ddf0da1
--- /dev/null
+++ b/mm/kwatch/.kunitconfig
@@ -0,0 +1,9 @@
+CONFIG_KUNIT=y
+CONFIG_KWATCH=y
+CONFIG_KWATCH_KUNIT_TEST=y
+CONFIG_PERF_EVENTS=y
+CONFIG_HAVE_HW_BREAKPOINT=y
+CONFIG_HAVE_REINSTALL_HW_BREAKPOINT=y
+CONFIG_KPROBES=y
+CONFIG_KRETPROBES=y
+CONFIG_PRINTK=y
diff --git a/mm/kwatch/Kconfig b/mm/kwatch/Kconfig
index 9daf6d4463ef..6ec9aa448ece 100644
--- a/mm/kwatch/Kconfig
+++ b/mm/kwatch/Kconfig
@@ -14,3 +14,15 @@ config KWATCH
exact instruction causing the illegal access.
If unsure, say N.
+
+config KWATCH_KUNIT_TEST
+ bool "KUnit tests for KWatch" if !KUNIT_ALL_TESTS
+ # Built into the kwatch module, so it must be y; a bool cannot be
+ # enabled when KWATCH is a module (KWATCH=m would force it off).
+ depends on KWATCH=y && KUNIT
+ default KUNIT_ALL_TESTS
+ help
+ Enable KUnit tests for the KWatch kernel module.
+ This suite tests the core parsing logic, the pointer-chasing
+ finite state machine, and edge cases involving complex watchpoint
+ expressions. If unsure, say N.
diff --git a/mm/kwatch/Makefile b/mm/kwatch/Makefile
index 02d7917602f1..1d223d73b461 100644
--- a/mm/kwatch/Makefile
+++ b/mm/kwatch/Makefile
@@ -1,3 +1,4 @@
obj-$(CONFIG_KWATCH) += kwatch.o
kwatch-y := core.o deref.o task_ctx.o hwbp.o probe.o anchor.o
+kwatch-$(CONFIG_KWATCH_KUNIT_TEST) += deref_test.o
diff --git a/mm/kwatch/deref_test.c b/mm/kwatch/deref_test.c
new file mode 100644
index 000000000000..35919dd24d92
--- /dev/null
+++ b/mm/kwatch/deref_test.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <kunit/test.h>
+#include "kwatch.h"
+#include <linux/string.h>
+
+static void kwatch_test_parse_deref_chain(struct kunit *test)
+{
+ struct kwatch_config cfg;
+ int ret;
+
+ // Test 1: stack
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "stack");
+ KUNIT_EXPECT_EQ(test, ret, 0);
+ KUNIT_EXPECT_EQ(test, cfg.base, KWATCH_BASE_STACK);
+ KUNIT_EXPECT_EQ(test, cfg.offset_count, 1);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[0], 0);
+
+ // Test 2: arg1
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "arg1");
+ KUNIT_EXPECT_EQ(test, ret, 0);
+ KUNIT_EXPECT_EQ(test, cfg.base, KWATCH_BASE_ARG1);
+ KUNIT_EXPECT_EQ(test, cfg.offset_count, 1);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[0], 0);
+
+ // Test 3: arg6+8
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "arg6+8");
+ KUNIT_EXPECT_EQ(test, ret, 0);
+ KUNIT_EXPECT_EQ(test, cfg.base, KWATCH_BASE_ARG6);
+ KUNIT_EXPECT_EQ(test, cfg.offset_count, 1);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[0], 8);
+
+ // Test 4: arg2-16
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "arg2-16");
+ KUNIT_EXPECT_EQ(test, ret, 0);
+ KUNIT_EXPECT_EQ(test, cfg.base, KWATCH_BASE_ARG2);
+ KUNIT_EXPECT_EQ(test, cfg.offset_count, 1);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[0], -16);
+
+ // Test 5: arg3->8
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "arg3->8");
+ KUNIT_EXPECT_EQ(test, ret, 0);
+ KUNIT_EXPECT_EQ(test, cfg.base, KWATCH_BASE_ARG3);
+ KUNIT_EXPECT_EQ(test, cfg.offset_count, 2);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[0], 0);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[1], 8);
+
+ // Test 6: arg4+8->16
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "arg4+8->16");
+ KUNIT_EXPECT_EQ(test, ret, 0);
+ KUNIT_EXPECT_EQ(test, cfg.base, KWATCH_BASE_ARG4);
+ KUNIT_EXPECT_EQ(test, cfg.offset_count, 2);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[0], 8);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[1], 16);
+
+ // Test 7: arg5-8->-16
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "arg5-8->-16");
+ KUNIT_EXPECT_EQ(test, ret, 0);
+ KUNIT_EXPECT_EQ(test, cfg.base, KWATCH_BASE_ARG5);
+ KUNIT_EXPECT_EQ(test, cfg.offset_count, 2);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[0], -8);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[1], -16);
+
+ // Test 8: stack->0->8
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "stack->0->8");
+ KUNIT_EXPECT_EQ(test, ret, 0);
+ KUNIT_EXPECT_EQ(test, cfg.base, KWATCH_BASE_STACK);
+ KUNIT_EXPECT_EQ(test, cfg.offset_count, 3);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[0], 0);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[1], 0);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[2], 8);
+
+ // Test 9: arg1->+8
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "arg1->+8");
+ KUNIT_EXPECT_EQ(test, ret, 0);
+ KUNIT_EXPECT_EQ(test, cfg.base, KWATCH_BASE_ARG1);
+ KUNIT_EXPECT_EQ(test, cfg.offset_count, 2);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[0], 0);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[1], 8);
+
+ // Test 9.1: arg1-> (implicit 0 should fail)
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "arg1->");
+ KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+
+ // Test 9.2: stack->->8 (implicit 0 should fail)
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "stack->->8");
+ KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+
+ // Test 10: Invalid base
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "invalid_base");
+ KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+
+ // Test 11: Invalid offset
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "arg1+abc");
+ KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+
+ // Test 12: Invalid arg
+ memset(&cfg, 0, sizeof(cfg));
+ ret = kwatch_deref_parse(&cfg, "arg7");
+ KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+
+ // Test 13: Absolute address. Use a width-appropriate literal: a 64-bit
+ // address would overflow unsigned long and fail kstrtoul() on 32-bit.
+ memset(&cfg, 0, sizeof(cfg));
+#if BITS_PER_LONG == 64
+ ret = kwatch_deref_parse(&cfg, "0xffffffff81000000+8");
+#else
+ ret = kwatch_deref_parse(&cfg, "0xc1000000+8");
+#endif
+ KUNIT_EXPECT_EQ(test, ret, 0);
+ KUNIT_EXPECT_EQ(test, cfg.base, KWATCH_BASE_ABS_ADDR);
+#if BITS_PER_LONG == 64
+ KUNIT_EXPECT_EQ(test, cfg.sym_addr, 0xffffffff81000000UL);
+#else
+ KUNIT_EXPECT_EQ(test, cfg.sym_addr, 0xc1000000UL);
+#endif
+ KUNIT_EXPECT_EQ(test, cfg.offset_count, 1);
+ KUNIT_EXPECT_EQ(test, cfg.offsets[0], 8);
+}
+
+static struct kunit_case kwatch_deref_test_cases[] = {
+ KUNIT_CASE(kwatch_test_parse_deref_chain),
+ {}
+};
+
+static struct kunit_suite kwatch_deref_test_suite = {
+ .name = "kwatch_deref",
+ .test_cases = kwatch_deref_test_cases,
+};
+
+kunit_test_suite(kwatch_deref_test_suite);
+
+MODULE_DESCRIPTION("KUnit tests for the KWatch watch expression parser");
+MODULE_LICENSE("GPL");
--
2.53.0
next prev parent reply other threads:[~2026-07-17 13:07 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-17 12:50 [RFC PATCH v2 00/13] mm/kwatch: dynamic hardware watchpoints for hunting memory corruption Jinchao Wang
2026-07-17 13:02 ` [RFC PATCH v2 01/13] arch: add HAVE_REINSTALL_HW_BREAKPOINT Jinchao Wang
2026-07-17 13:02 ` [RFC PATCH v2 02/13] x86/hw_breakpoint: Unify breakpoint install/uninstall Jinchao Wang
2026-07-17 13:03 ` [RFC PATCH v2 03/13] x86/hw_breakpoint: Add arch_reinstall_hw_breakpoint Jinchao Wang
2026-07-17 13:03 ` [RFC PATCH v2 04/13] HWBP: Add modify_wide_hw_breakpoint_local() API Jinchao Wang
2026-07-17 13:04 ` [RFC PATCH v2 05/13] mm/kwatch: add watch expression parser and dereference engine Jinchao Wang
2026-07-17 13:04 ` [RFC PATCH v2 06/13] mm/kwatch: add lockless per-task context pool Jinchao Wang
2026-07-17 13:04 ` [RFC PATCH v2 07/13] stacktrace: export stack_trace_save_regs() Jinchao Wang
2026-07-17 13:05 ` [RFC PATCH v2 08/13] mm/kwatch: add hardware breakpoint backend Jinchao Wang
2026-07-17 13:05 ` [RFC PATCH v2 09/13] mm/kwatch: add probe lifecycle runtime Jinchao Wang
2026-07-17 13:06 ` [RFC PATCH v2 10/13] mm/kwatch: add anchor thread for global watchpoints Jinchao Wang
2026-07-17 13:06 ` [RFC PATCH v2 11/13] mm/kwatch: add debugfs control plane Jinchao Wang
2026-07-17 13:07 ` Jinchao Wang [this message]
2026-07-17 13:07 ` [RFC PATCH v2 13/13] Documentation/dev-tools: document KWatch Jinchao Wang
2026-07-17 13:41 ` [RFC PATCH v2 00/13] mm/kwatch: dynamic hardware watchpoints for hunting memory corruption Dave Hansen
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