[PATCH v6 1/2] x86/kexec: fix potential cmem->ranges out of memory

[PATCH v6 1/2] x86/kexec: fix potential cmem->ranges out of memory

[Coiby Xu]

From: fuqiang wang <fuqiang.wang@easystack.cn>

In memmap_exclude_ranges(), elfheader will be excluded from crashk_res.
In the current x86 architecture code, the elfheader is always allocated
at crashk_res.start. It seems that there won't be a new split range.
But it depends on the allocation position of elfheader in crashk_res. To
avoid potential out of memory in future, add a extra slot. Otherwise
loading the kdump kernel will fail because crash_exclude_mem_range will
return -ENOMEM. random kexec_buf for passing dm crypt keys may cause a
range split too,
add another extra slot here.

The similar issue also exists in fill_up_crash_elf_data(). The range to
be excluded is [0, 1M], start (0) is special and will not appear in the
middle of existing cmem->ranges[]. But in cast the low 1M could be
changed in the future, add a extra slot too.

Previously discussed link:
[1] https://lore.kernel.org/kexec/ZXk2oBf%2FT1Ul6o0c@MiWiFi-R3L-srv/
[2] https://lore.kernel.org/kexec/273284e8-7680-4f5f-8065-c5d780987e59@easystack.cn/
[3] https://lore.kernel.org/kexec/ZYQ6O%2F57sHAPxTHm@MiWiFi-R3L-srv/

Signed-off-by: fuqiang wang <fuqiang.wang@easystack.cn>
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>
---
v5->v6:
- rebase onto v6.17-rc4

v4->v5 (Baoquan):
- This is on top of Coiby's LUKS patchset in branch mm-nonmm-unstable of
  akpm/mm.git. I did some adaption based on Coiby's patches.
- [PATCH v9 0/8] Support kdump with LUKS encryption by reusing LUKS volume keys

 arch/x86/kernel/crash.c | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index c6b12bed173d..5efdcd95a283 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -165,8 +165,18 @@ static struct crash_mem *fill_up_crash_elf_data(void)
 	/*
 	 * Exclusion of crash region, crashk_low_res and/or crashk_cma_ranges
 	 * may cause range splits. So add extra slots here.
+	 *
+	 * Exclusion of low 1M may not cause another range split, because the
+	 * range of exclude is [0, 1M] and the condition for splitting a new
+	 * region is that the start, end parameters are both in a certain
+	 * existing region in cmem and cannot be equal to existing region's
+	 * start or end. Obviously, the start of [0, 1M] cannot meet this
+	 * condition.
+	 *
+	 * But in order to lest the low 1M could be changed in the future,
+	 * (e.g. [start, 1M]), add a extra slot.
 	 */
-	nr_ranges += 2 + crashk_cma_cnt;
+	nr_ranges += 3 + crashk_cma_cnt;
 	cmem = vzalloc(struct_size(cmem, ranges, nr_ranges));
 	if (!cmem)
 		return NULL;
@@ -323,10 +333,15 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
 	struct crash_mem *cmem;
 
 	/*
-	 * Using random kexec_buf for passing dm crypt keys may cause a range
-	 * split. So use two slots here.
+	 * In the current x86 architecture code, the elfheader is always
+	 * allocated at crashk_res.start. But it depends on the allocation
+	 * position of elfheader in crashk_res. To avoid potential out of
+	 * bounds in future, add an extra slot.
+	 *
+	 * And using random kexec_buf for passing dm crypt keys may cause a
+	 * range split too, add another extra slot here.
 	 */
-	nr_ranges = 2;
+	nr_ranges = 3;
 	cmem = vzalloc(struct_size(cmem, ranges, nr_ranges));
 	if (!cmem)
 		return -ENOMEM;

base-commit: b320789d6883cc00ac78ce83bccbfe7ed58afcf0
-- 
2.51.0

[PATCH v6 2/2] crash: Add KUnit tests for crash_exclude_mem_range

[Coiby Xu]

crash_exclude_mem_range seems to be a simple function but there have been
multiple attempts to fix it,
 - commit a2e9a95d2190 ("kexec: Improve & fix crash_exclude_mem_range()
   to handle overlapping ranges")
 - commit 6dff31597264 ("crash_core: fix and simplify the logic of
   crash_exclude_mem_range()")

So add a set of unit tests to verify the correctness of current
implementation. Shall we change the function in the future, the unit
tests can also help prevent any regression. For example, we may make the
function smarter by allocating extra crash_mem range on demand thus
there is no need for the caller to foresee any memory range split or
address -ENOMEM failure.

The testing strategy is to verify the correctness of base case. The
base case is there is one to-be-excluded range A and one existing range
B. Then we can exhaust all possibilities of the position of A regarding
B. For example, here are two combinations,
    Case: A is completely inside B (causes split)
      Original:       [----B----]
      Exclude:          {--A--}
      Result:         [B1] .. [B2]

    Case: A overlaps B's left part
      Original:       [----B----]
      Exclude:  {---A---}
      Result:           [..B..]

In theory we can prove the correctness by induction,
   - Base case: crash_exclude_mem_range is correct in the case where n=1
     (n is the number of existing ranges).
   - Inductive step: If crash_exclude_mem_range is correct for n=k
     existing ranges, then the it's also correct for n=k+1 ranges.

But for the sake of simplicity, simply use unit tests to cover the base
case together with two regression tests.

Note most of exclude_single_range_test code is generated by Google
Gemini with some small tweaks. The function specification, function body
and the exhausting test strategy are presented as prompts.

Signed-off-by: Coiby Xu <coxu@redhat.com>
Assisted-by: Google Gemini
---
 kernel/Kconfig.kexec     |  11 ++
 kernel/Makefile          |   1 +
 kernel/crash_core.c      |  14 ++
 kernel/crash_core_test.c | 343 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 369 insertions(+)
 create mode 100644 kernel/crash_core_test.c

diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec
index 1224dd937df0..422270d64820 100644
--- a/kernel/Kconfig.kexec
+++ b/kernel/Kconfig.kexec
@@ -148,6 +148,17 @@ config CRASH_DM_CRYPT_CONFIGS
 	  CRASH_DM_CRYPT cannot directly select CONFIGFS_FS, because that
 	  is required to be built-in.
 
+config CRASH_DUMP_KUNIT_TEST
+	tristate "Unit Tests for kernel crash dumps" if !KUNIT_ALL_TESTS
+	depends on CRASH_DUMP && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This option builds KUnit unit tests for kernel crash dumps. The unit
+	  tests will be used to verify the correctness of covered functions and
+	  also prevent any regression.
+
+	  If unsure, say N.
+
 config CRASH_HOTPLUG
 	bool "Update the crash elfcorehdr on system configuration changes"
 	default y
diff --git a/kernel/Makefile b/kernel/Makefile
index c60623448235..216a7dfc3a68 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -78,6 +78,7 @@ obj-$(CONFIG_CRASH_RESERVE) += crash_reserve.o
 obj-$(CONFIG_KEXEC_CORE) += kexec_core.o
 obj-$(CONFIG_CRASH_DUMP) += crash_core.o
 obj-$(CONFIG_CRASH_DM_CRYPT) += crash_dump_dm_crypt.o
+obj-$(CONFIG_CRASH_DUMP_KUNIT_TEST) += crash_core_test.o
 obj-$(CONFIG_KEXEC) += kexec.o
 obj-$(CONFIG_KEXEC_FILE) += kexec_file.o
 obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index a4ef79591eb2..961a035aaea7 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -274,6 +274,20 @@ int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
 	return 0;
 }
 
+/**
+ * crash_exclude_mem_range - exclude a mem range for existing ranges
+ * @mem: mem->range contains an array of ranges sorted in ascending order
+ * @mstart: the start of to-be-excluded range
+ * @mend: the start of to-be-excluded range
+ *
+ * If you are unsure if a range split will happen, to avoid function call
+ * failure because of -ENOMEM, always make sure
+ *    mem->max_nr_ranges == mem->nr_ranges + 1
+ * before calling the function each time.
+ *
+ * returns 0 if a memory range is excluded successfully
+ * return -ENOMEM if mem->ranges doesn't have space to hold split ranges
+ */
 int crash_exclude_mem_range(struct crash_mem *mem,
 			    unsigned long long mstart, unsigned long long mend)
 {
diff --git a/kernel/crash_core_test.c b/kernel/crash_core_test.c
new file mode 100644
index 000000000000..8aadf6801530
--- /dev/null
+++ b/kernel/crash_core_test.c
@@ -0,0 +1,343 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <kunit/test.h>
+#include <linux/crash_core.h> // For struct crash_mem and struct range if defined there
+
+// Helper to create and initialize crash_mem
+static struct crash_mem *create_crash_mem(struct kunit *test, unsigned int max_ranges,
+					  unsigned int nr_initial_ranges,
+					  const struct range *initial_ranges)
+{
+	struct crash_mem *mem;
+	size_t alloc_size;
+
+	// Check if max_ranges can even hold initial_ranges
+	if (max_ranges < nr_initial_ranges) {
+		kunit_err(test, "max_ranges (%u) < nr_initial_ranges (%u)\n",
+			  max_ranges, nr_initial_ranges);
+		return NULL;
+	}
+
+	alloc_size = sizeof(struct crash_mem) + (size_t)max_ranges * sizeof(struct range);
+	mem = kunit_kzalloc(test, alloc_size, GFP_KERNEL);
+	if (!mem) {
+		kunit_err(test, "Failed to allocate crash_mem\n");
+		return NULL;
+	}
+
+	mem->max_nr_ranges = max_ranges;
+	mem->nr_ranges = nr_initial_ranges;
+	if (initial_ranges && nr_initial_ranges > 0) {
+		memcpy(mem->ranges, initial_ranges,
+		       nr_initial_ranges * sizeof(struct range));
+	}
+
+	return mem;
+}
+
+// Helper to compare ranges for assertions
+static void assert_ranges_equal(struct kunit *test,
+				const struct range *actual_ranges,
+				unsigned int actual_nr_ranges,
+				const struct range *expected_ranges,
+				unsigned int expected_nr_ranges,
+				const char *case_name)
+{
+	unsigned int i;
+
+	KUNIT_ASSERT_EQ_MSG(test, expected_nr_ranges, actual_nr_ranges,
+			    "%s: Number of ranges mismatch.", case_name);
+
+	for (i = 0; i < expected_nr_ranges; i++) {
+		KUNIT_ASSERT_EQ_MSG(test, expected_ranges[i].start, actual_ranges[i].start,
+				    "%s: Range %u start mismatch.", case_name, i);
+		KUNIT_ASSERT_EQ_MSG(test, expected_ranges[i].end, actual_ranges[i].end,
+				    "%s: Range %u end mismatch.", case_name, i);
+	}
+}
+
+// Structure for test parameters
+struct exclude_test_param {
+	const char *description;
+	unsigned long long exclude_start;
+	unsigned long long exclude_end;
+	unsigned int initial_max_ranges;
+	const struct range *initial_ranges;
+	unsigned int initial_nr_ranges;
+	const struct range *expected_ranges;
+	unsigned int expected_nr_ranges;
+	int expected_ret;
+};
+
+static void run_exclude_test_case(struct kunit *test, const struct exclude_test_param *params)
+{
+	struct crash_mem *mem;
+	int ret;
+
+	kunit_info(test, "%s", params->description);
+
+	mem = create_crash_mem(test, params->initial_max_ranges,
+			       params->initial_nr_ranges, params->initial_ranges);
+	if (!mem)
+		return; // Error already logged by create_crash_mem or kunit_kzalloc
+
+	ret = crash_exclude_mem_range(mem, params->exclude_start, params->exclude_end);
+
+	KUNIT_ASSERT_EQ_MSG(test, params->expected_ret, ret,
+			    "%s: Return value mismatch.", params->description);
+
+	if (params->expected_ret == 0) {
+		assert_ranges_equal(test, mem->ranges, mem->nr_ranges,
+				    params->expected_ranges, params->expected_nr_ranges,
+				    params->description);
+	} else {
+		// If an error is expected, nr_ranges might still be relevant to check
+		// depending on the exact point of failure. For ENOMEM on split,
+		// nr_ranges shouldn't have changed.
+		KUNIT_ASSERT_EQ_MSG(test, params->initial_nr_ranges,
+				    mem->nr_ranges,
+				    "%s: Number of ranges mismatch on error.",
+				    params->description);
+	}
+}
+
+/*
+ * Test Strategy 1: One to-be-excluded range A and one existing range B.
+ *
+ * Exhaust all possibilities of the position of A regarding B.
+ */
+
+static const struct range single_range_b = { .start = 100, .end = 199 };
+
+static const struct exclude_test_param exclude_single_range_test_data[] = {
+	{
+		.description = "1.1: A is left of B, no overlap",
+		.exclude_start = 10, .exclude_end = 50,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = &single_range_b, .expected_nr_ranges = 1,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.2: A's right boundary touches B's left boundary",
+		.exclude_start = 10, .exclude_end = 99,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = &single_range_b, .expected_nr_ranges = 1,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.3: A overlaps B's left part",
+		.exclude_start = 50, .exclude_end = 149,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = (const struct range[]){{ .start = 150, .end = 199 }},
+		.expected_nr_ranges = 1,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.4: A is completely inside B",
+		.exclude_start = 120, .exclude_end = 179,
+		.initial_max_ranges = 2, // Needs space for split
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = (const struct range[]){
+			{ .start = 100, .end = 119 },
+			{ .start = 180, .end = 199 }
+		},
+		.expected_nr_ranges = 2,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.5: A overlaps B's right part",
+		.exclude_start = 150, .exclude_end = 249,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = (const struct range[]){{ .start = 100, .end = 149 }},
+		.expected_nr_ranges = 1,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.6: A's left boundary touches B's right boundary",
+		.exclude_start = 200, .exclude_end = 250,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = &single_range_b, .expected_nr_ranges = 1,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.7: A is right of B, no overlap",
+		.exclude_start = 250, .exclude_end = 300,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = &single_range_b, .expected_nr_ranges = 1,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.8: A completely covers B and extends beyond",
+		.exclude_start = 50, .exclude_end = 250,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = NULL, .expected_nr_ranges = 0,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.9: A covers B and extends to the left",
+		.exclude_start = 50, .exclude_end = 199, // A ends exactly where B ends
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = NULL, .expected_nr_ranges = 0,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.10: A covers B and extends to the right",
+		.exclude_start = 100, .exclude_end = 250, // A starts exactly where B starts
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = NULL, .expected_nr_ranges = 0,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.11: A is identical to B",
+		.exclude_start = 100, .exclude_end = 199,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = NULL, .expected_nr_ranges = 0,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.12: A is a point, left of B, no overlap",
+		.exclude_start = 10, .exclude_end = 10,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = &single_range_b, .expected_nr_ranges = 1,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.13: A is a point, at start of B",
+		.exclude_start = 100, .exclude_end = 100,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = (const struct range[]){{ .start = 101, .end = 199 }},
+		.expected_nr_ranges = 1,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.14: A is a point, in middle of B (causes split)",
+		.exclude_start = 150, .exclude_end = 150,
+		.initial_max_ranges = 2, // Needs space for split
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = (const struct range[]){
+			{ .start = 100, .end = 149 },
+			{ .start = 151, .end = 199 }
+		},
+		.expected_nr_ranges = 2,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.15: A is a point, at end of B",
+		.exclude_start = 199, .exclude_end = 199,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = (const struct range[]){{ .start = 100, .end = 198 }},
+		.expected_nr_ranges = 1,
+		.expected_ret = 0,
+	},
+	{
+		.description = "1.16: A is a point, right of B, no overlap",
+		.exclude_start = 250, .exclude_end = 250,
+		.initial_max_ranges = 1,
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = &single_range_b, .expected_nr_ranges = 1,
+		.expected_ret = 0,
+	},
+	// ENOMEM case for single range split
+	{
+		.description = "1.17: A completely inside B (split), no space (ENOMEM)",
+		.exclude_start = 120, .exclude_end = 179,
+		.initial_max_ranges = 1, // Not enough for split
+		.initial_ranges = &single_range_b, .initial_nr_ranges = 1,
+		.expected_ranges = NULL, // Not checked on error by assert_ranges_equal for content
+		.expected_nr_ranges = 1, // Should remain unchanged
+		.expected_ret = -ENOMEM,
+	},
+};
+
+
+static void exclude_single_range_test(struct kunit *test)
+{
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(exclude_single_range_test_data); i++) {
+		kunit_log(KERN_INFO, test, "Running: %s", exclude_single_range_test_data[i].description);
+		run_exclude_test_case(test, &exclude_single_range_test_data[i]);
+		// KUnit will stop on first KUNIT_ASSERT failure within run_exclude_test_case
+	}
+}
+
+/*
+ * Test Strategy 2: Regression test.
+ */
+
+static const struct exclude_test_param exclude_range_regression_test_data[] = {
+	// Test data from commit a2e9a95d2190
+	{
+		.description = "2.1: exclude low 1M",
+		.exclude_start = 0, .exclude_end = (1 << 20) - 1,
+		.initial_max_ranges = 3,
+		.initial_ranges = (const struct range[]){
+			{ .start = 0, .end = 0x3efff },
+			{ .start = 0x3f000, .end = 0x3ffff },
+			{ .start = 0x40000, .end = 0x9ffff }
+		},
+		.initial_nr_ranges = 3,
+		.expected_nr_ranges = 0,
+		.expected_ret = 0,
+	},
+	// Test data from https://lore.kernel.org/all/ZXrY7QbXAlxydsSC@MiWiFi-R3L-srv/T/#u
+	{
+		.description = "2.2: when range out of bound",
+		.exclude_start = 100, .exclude_end = 200,
+		.initial_max_ranges = 3,
+		.initial_ranges = (const struct range[]){
+			{ .start = 1, .end = 299 },
+			{ .start = 401, .end = 1000 },
+			{ .start = 1001, .end = 2000 }
+		},
+		.initial_nr_ranges = 3,
+		.expected_ranges = NULL, // Not checked on error by assert_ranges_equal for content
+		.expected_nr_ranges = 3, // Should remain unchanged
+		.expected_ret = -ENOMEM
+	},
+
+};
+
+
+static void exclude_range_regression_test(struct kunit *test)
+{
+	size_t i;
+
+	for (i = 0; i < ARRAY_SIZE(exclude_range_regression_test_data); i++) {
+		kunit_log(KERN_INFO, test, "Running: %s", exclude_range_regression_test_data[i].description);
+		run_exclude_test_case(test, &exclude_range_regression_test_data[i]);
+		// KUnit will stop on first KUNIT_ASSERT failure within run_exclude_test_case
+	}
+}
+
+/*
+ * KUnit Test Suite
+ */
+static struct kunit_case crash_exclude_mem_range_test_cases[] = {
+	KUNIT_CASE(exclude_single_range_test),
+	KUNIT_CASE(exclude_range_regression_test),
+	{}
+};
+
+static struct kunit_suite crash_exclude_mem_range_suite = {
+	.name = "crash_exclude_mem_range_tests",
+	.test_cases = crash_exclude_mem_range_test_cases,
+	// .init and .exit can be NULL if not needed globally for the suite
+};
+
+kunit_test_suite(crash_exclude_mem_range_suite);
+
+MODULE_DESCRIPTION("crash dump KUnit test suite");
+MODULE_LICENSE("GPL");
-- 
2.51.0

Re: [PATCH v6 2/2] crash: Add KUnit tests for crash_exclude_mem_range

[kernel test robot]

Hi Coiby,

kernel test robot noticed the following build errors:

[auto build test ERROR on b320789d6883cc00ac78ce83bccbfe7ed58afcf0]

url:    https://github.com/intel-lab-lkp/linux/commits/Coiby-Xu/crash-Add-KUnit-tests-for-crash_exclude_mem_range/20250904-174105
base:   b320789d6883cc00ac78ce83bccbfe7ed58afcf0
patch link:    https://lore.kernel.org/r/20250904093855.1180154-2-coxu%40redhat.com
patch subject: [PATCH v6 2/2] crash: Add KUnit tests for crash_exclude_mem_range
config: x86_64-randconfig-073-20250908 (https://download.01.org/0day-ci/archive/20250909/202509090415.cOytgte4-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250909/202509090415.cOytgte4-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202509090415.cOytgte4-lkp@intel.com/

All errors (new ones prefixed by >>, old ones prefixed by <<):

>> ERROR: modpost: "crash_exclude_mem_range" [kernel/crash_core_test.ko] undefined!

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v6 2/2] crash: Add KUnit tests for crash_exclude_mem_range

[Coiby Xu]

On Tue, Sep 09, 2025 at 05:25:17AM +0800, kernel test robot wrote:
>Hi Coiby,

Hi,

>
>kernel test robot noticed the following build errors:
>
>[auto build test ERROR on b320789d6883cc00ac78ce83bccbfe7ed58afcf0]
>
>url:    https://github.com/intel-lab-lkp/linux/commits/Coiby-Xu/crash-Add-KUnit-tests-for-crash_exclude_mem_range/20250904-174105
>base:   b320789d6883cc00ac78ce83bccbfe7ed58afcf0
>patch link:    https://lore.kernel.org/r/20250904093855.1180154-2-coxu%40redhat.com
>patch subject: [PATCH v6 2/2] crash: Add KUnit tests for crash_exclude_mem_range
>config: x86_64-randconfig-073-20250908 (https://download.01.org/0day-ci/archive/20250909/202509090415.cOytgte4-lkp@intel.com/config)
>compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
>reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250909/202509090415.cOytgte4-lkp@intel.com/reproduce)
>
>If you fix the issue in a separate patch/commit (i.e. not just a new version of
>the same patch/commit), kindly add following tags
>| Reported-by: kernel test robot <lkp@intel.com>
>| Closes: https://lore.kernel.org/oe-kbuild-all/202509090415.cOytgte4-lkp@intel.com/
>
>All errors (new ones prefixed by >>, old ones prefixed by <<):
>
>>> ERROR: modpost: "crash_exclude_mem_range" [kernel/crash_core_test.ko] undefined!

Thanks for reporting this problem. This issue has already been fixed by
Andrew [1][2] earlier.

This issue happens because the KUnit tests can be built and run as a
kernel module. 

[1] https://lore.kernel.org/mm-commits/20250905031921.E0A26C4CEF0@smtp.kernel.org/
[2] https://lore.kernel.org/mm-commits/20250914001748.77104C4CEEB@smtp.kernel.org/

>
>-- 
>0-DAY CI Kernel Test Service
>https://github.com/intel/lkp-tests/wiki
>

-- 
Best regards,
Coiby