[PATCH v3 0/8] char: misc: Various cleanup for miscdevice

[PATCH v3 0/8] char: misc: Various cleanup for miscdevice

[Zijun Hu]

This patch series is to do cleanup for:

- Miscdevice APIs
- Miscdevice kunit test cases
- Drivers which use miscdevice APIs

Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
---
Previous discussion link:
https://lore.kernel.org/all/20250620-rfc_miscdev-v1-1-fda25d502a37@oss.qualcomm.com

---
Changes in v3:
- Drop the change which allocates 4 fixed minors for watchdog
- Correct tile and commit message
- Link to v2: https://lore.kernel.org/r/20250701-rfc_miscdev-v2-0-3eb22bf533be@oss.qualcomm.com

---
Zijun Hu (8):
      char: misc: Move drivers/misc/misc_minor_kunit.c to drivers/char/
      char: misc: Adapt and add test cases for simple minor space division
      char: misc: Disallow registering miscdevice whose minor > MISC_DYNAMIC_MINOR
      char: misc: Add a reentry test case about dynamic minor request
      char: misc: Make registering miscdevice reentry who wants dynamic minor
      char: misc: Does not request module for miscdevice with dynamic minor
      char: misc: Register fixed minor EISA_EEPROM_MINOR in linux/miscdevice.h
      sparc: kernel: apc: Remove macro APC_MINOR definition

 arch/sparc/kernel/apc.c                   |  3 +-
 drivers/char/Makefile                     |  1 +
 drivers/char/misc.c                       | 16 +++++-
 drivers/{misc => char}/misc_minor_kunit.c | 95 +++++++++++++++++++++----------
 drivers/misc/Makefile                     |  1 -
 drivers/parisc/eisa_eeprom.c              |  2 -
 include/linux/miscdevice.h                |  9 +++
 7 files changed, 89 insertions(+), 38 deletions(-)
---
base-commit: 626e89412dfb88766d90d842af4d9ec432d8526f
change-id: 20250701-rfc_miscdev-35dd3310c7c0

Best regards,
-- 
Zijun Hu <zijun.hu@oss.qualcomm.com>

[PATCH v3 1/8] char: misc: Move drivers/misc/misc_minor_kunit.c to drivers/char/

[Zijun Hu]

From: Zijun Hu <zijun.hu@oss.qualcomm.com>

drivers/misc/misc_minor_kunit.c is to test APIs defined in
drivers/char/misc.c, but is not in the same directory as the later.

Move misc_minor_kunit.c to drivers/char/.

Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
---
 drivers/char/Makefile                     | 1 +
 drivers/{misc => char}/misc_minor_kunit.c | 0
 drivers/misc/Makefile                     | 1 -
 3 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index e9b360cdc99a7fee9c70eabcffe9caf763552aa2..7d10d92edcedbff5957d6c5c3426aa9400c94e43 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -6,6 +6,7 @@
 obj-y				+= mem.o random.o
 obj-$(CONFIG_TTY_PRINTK)	+= ttyprintk.o
 obj-y				+= misc.o
+obj-$(CONFIG_TEST_MISC_MINOR)   += misc_minor_kunit.o
 obj-$(CONFIG_ATARI_DSP56K)	+= dsp56k.o
 obj-$(CONFIG_VIRTIO_CONSOLE)	+= virtio_console.o
 obj-$(CONFIG_UV_MMTIMER)	+= uv_mmtimer.o
diff --git a/drivers/misc/misc_minor_kunit.c b/drivers/char/misc_minor_kunit.c
similarity index 100%
rename from drivers/misc/misc_minor_kunit.c
rename to drivers/char/misc_minor_kunit.c
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 917b9a7183aa1db63cc4049c042c3437f6756a1a..94f44e6c2db79dedc3839bbfb53e10cde103fbc6 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -23,7 +23,6 @@ obj-$(CONFIG_SENSORS_BH1770)	+= bh1770glc.o
 obj-$(CONFIG_SENSORS_APDS990X)	+= apds990x.o
 obj-$(CONFIG_ENCLOSURE_SERVICES) += enclosure.o
 obj-$(CONFIG_KGDB_TESTS)	+= kgdbts.o
-obj-$(CONFIG_TEST_MISC_MINOR)	+= misc_minor_kunit.o
 obj-$(CONFIG_SGI_XP)		+= sgi-xp/
 obj-$(CONFIG_SGI_GRU)		+= sgi-gru/
 obj-$(CONFIG_SMPRO_ERRMON)	+= smpro-errmon.o

-- 
2.34.1

[PATCH v3 2/8] char: misc: Adapt and add test cases for simple minor space division

[Zijun Hu]

From: Zijun Hu <zijun.hu@oss.qualcomm.com>

Adapt and add test cases for next change which Regards minor
which > MISC_DYNAMIC_MINOR as invalid parameter when register
miscdevice, hence get a simple minor space division below:

|<  255 : Fixed minor code
|== 255 : Indicator to request dynamic minor code
|>  255 : Dynamic minor code requested, 1048320 minor codes totally.

Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
---
 drivers/char/misc_minor_kunit.c | 51 +++++++++++++++++------------------------
 1 file changed, 21 insertions(+), 30 deletions(-)

diff --git a/drivers/char/misc_minor_kunit.c b/drivers/char/misc_minor_kunit.c
index 30eceac5f1b6402b0f918af6f56602ed1a6c14ec..81e2ef488a6f6ae7138c7dd8bcbeffe38aa65933 100644
--- a/drivers/char/misc_minor_kunit.c
+++ b/drivers/char/misc_minor_kunit.c
@@ -7,12 +7,6 @@
 #include <linux/file.h>
 #include <linux/init_syscalls.h>
 
-/* dynamic minor (2) */
-static struct miscdevice dev_dynamic_minor = {
-	.minor  = 2,
-	.name   = "dev_dynamic_minor",
-};
-
 /* static minor (LCD_MINOR) */
 static struct miscdevice dev_static_minor = {
 	.minor  = LCD_MINOR,
@@ -25,16 +19,6 @@ static struct miscdevice dev_misc_dynamic_minor = {
 	.name   = "dev_misc_dynamic_minor",
 };
 
-static void kunit_dynamic_minor(struct kunit *test)
-{
-	int ret;
-
-	ret = misc_register(&dev_dynamic_minor);
-	KUNIT_EXPECT_EQ(test, 0, ret);
-	KUNIT_EXPECT_EQ(test, 2, dev_dynamic_minor.minor);
-	misc_deregister(&dev_dynamic_minor);
-}
-
 static void kunit_static_minor(struct kunit *test)
 {
 	int ret;
@@ -157,13 +141,7 @@ static bool is_valid_dynamic_minor(int minor)
 {
 	if (minor < 0)
 		return false;
-	if (minor == MISC_DYNAMIC_MINOR)
-		return false;
-	if (minor >= 0 && minor <= 15)
-		return false;
-	if (minor >= 128 && minor < MISC_DYNAMIC_MINOR)
-		return false;
-	return true;
+	return minor > MISC_DYNAMIC_MINOR;
 }
 
 static int miscdev_test_open(struct inode *inode, struct file *file)
@@ -557,7 +535,7 @@ static void __init miscdev_test_conflict(struct kunit *test)
 	 */
 	miscstat.minor = miscdyn.minor;
 	ret = misc_register(&miscstat);
-	KUNIT_EXPECT_EQ(test, ret, -EBUSY);
+	KUNIT_EXPECT_EQ(test, ret, -EINVAL);
 	if (ret == 0)
 		misc_deregister(&miscstat);
 
@@ -590,8 +568,9 @@ static void __init miscdev_test_conflict_reverse(struct kunit *test)
 	misc_deregister(&miscdyn);
 
 	ret = misc_register(&miscstat);
-	KUNIT_EXPECT_EQ(test, ret, 0);
-	KUNIT_EXPECT_EQ(test, miscstat.minor, miscdyn.minor);
+	KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+	if (ret == 0)
+		misc_deregister(&miscstat);
 
 	/*
 	 * Try to register a dynamic minor after registering a static minor
@@ -601,20 +580,32 @@ static void __init miscdev_test_conflict_reverse(struct kunit *test)
 	miscdyn.minor = MISC_DYNAMIC_MINOR;
 	ret = misc_register(&miscdyn);
 	KUNIT_EXPECT_EQ(test, ret, 0);
-	KUNIT_EXPECT_NE(test, miscdyn.minor, miscstat.minor);
+	KUNIT_EXPECT_EQ(test, miscdyn.minor, miscstat.minor);
 	KUNIT_EXPECT_TRUE(test, is_valid_dynamic_minor(miscdyn.minor));
 	if (ret == 0)
 		misc_deregister(&miscdyn);
+}
 
-	miscdev_test_can_open(test, &miscstat);
+/* Take minor(> MISC_DYNAMIC_MINOR) as invalid when register miscdevice */
+static void __init miscdev_test_invalid_input(struct kunit *test)
+{
+	struct miscdevice misc_test = {
+		.minor = MISC_DYNAMIC_MINOR + 1,
+		.name = "misc_test",
+		.fops = &miscdev_test_fops,
+	};
+	int ret;
 
-	misc_deregister(&miscstat);
+	ret = misc_register(&misc_test);
+	KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+	if (ret == 0)
+		misc_deregister(&misc_test);
 }
 
 static struct kunit_case test_cases[] = {
-	KUNIT_CASE(kunit_dynamic_minor),
 	KUNIT_CASE(kunit_static_minor),
 	KUNIT_CASE(kunit_misc_dynamic_minor),
+	KUNIT_CASE(miscdev_test_invalid_input),
 	KUNIT_CASE_PARAM(miscdev_test_twice, miscdev_gen_params),
 	KUNIT_CASE_PARAM(miscdev_test_duplicate_minor, miscdev_gen_params),
 	KUNIT_CASE(miscdev_test_duplicate_name),

-- 
2.34.1

[PATCH v3 3/8] char: misc: Disallow registering miscdevice whose minor > MISC_DYNAMIC_MINOR

[Zijun Hu]

From: Zijun Hu <zijun.hu@oss.qualcomm.com>

Currently, It is allowed to register miscdevice with minor > 255
which is defined by macro MISC_DYNAMIC_MINOR, and cause:

- Chaos regarding division and management of minor codes.
- Registering failure if the minor was allocated to other dynamic request.

Fortunately, in-kernel users have not had such usage yet.
Fix by refusing to register miscdevice whose minor > 255.

Also bring in a very simple minor code space division and management:

|<  255 : Fixed minor code
|== 255 : Indicator to request dynamic minor code
|>  255 : Dynamic minor code requested, 1048320 minor codes totally
And all fixed minors allocated should be registered in 'linux/miscdevice.h'

Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
---
 drivers/char/misc.c        | 6 ++++++
 include/linux/miscdevice.h | 8 ++++++++
 2 files changed, 14 insertions(+)

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 558302a64dd908aee30341547a5413df1af71459..b8e66466184fa21fb66d968db7950e0b5669ac43 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -210,6 +210,12 @@ int misc_register(struct miscdevice *misc)
 	int err = 0;
 	bool is_dynamic = (misc->minor == MISC_DYNAMIC_MINOR);
 
+	if (misc->minor > MISC_DYNAMIC_MINOR) {
+		pr_err("Invalid fixed minor %d for miscdevice '%s'\n",
+		       misc->minor, misc->name);
+		return -EINVAL;
+	}
+
 	INIT_LIST_HEAD(&misc->list);
 
 	mutex_lock(&misc_mtx);
diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
index 3e6deb00fc8535a7571f85489c74979e18385bad..565b88efeb23d02b7d91df1cd7df4bdcf2898224 100644
--- a/include/linux/miscdevice.h
+++ b/include/linux/miscdevice.h
@@ -71,6 +71,14 @@
 #define USERIO_MINOR		240
 #define VHOST_VSOCK_MINOR	241
 #define RFKILL_MINOR		242
+
+/*
+ * Misc char device minor code space division related to below macro:
+ *
+ * <  255  : Fixed minor code
+ * == 255  : Indicator to request dynamic minor code
+ * >  255  : Dynamic minor code requested, 1048320 minor codes totally.
+ */
 #define MISC_DYNAMIC_MINOR	255
 
 struct miscdevice {

-- 
2.34.1

[PATCH v3 4/8] char: misc: Add a reentry test case about dynamic minor request

[Zijun Hu]

From: Zijun Hu <zijun.hu@oss.qualcomm.com>

Add a case to test reentry about requesting dynamic minor:

1) Provide Both @dev_A and @dev_B want to request dynamic minor by
   initializing their minor to MISC_DYNAMIC_MINOR.

2) Register then de-register @dev_A.

3) Register @dev_B.

4) Register @dev_A again without reinitialization.

5) Check if @dev_A can be registered successfully.

Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
---
 drivers/char/misc_minor_kunit.c | 44 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/drivers/char/misc_minor_kunit.c b/drivers/char/misc_minor_kunit.c
index 81e2ef488a6f6ae7138c7dd8bcbeffe38aa65933..9f1f77c04f9f1be56bc94cab4127ecb941e128b2 100644
--- a/drivers/char/misc_minor_kunit.c
+++ b/drivers/char/misc_minor_kunit.c
@@ -602,6 +602,49 @@ static void __init miscdev_test_invalid_input(struct kunit *test)
 		misc_deregister(&misc_test);
 }
 
+/*
+ * Verify if @miscdyn_a can still be registered successfully without
+ * reinitialization even if its minor ever owned was requested by
+ * another miscdevice such as @miscdyn_b.
+ */
+static void __init miscdev_test_dynamic_reentry(struct kunit *test)
+{
+	struct miscdevice miscdyn_a = {
+		.name = "miscdyn_a",
+		.minor = MISC_DYNAMIC_MINOR,
+		.fops = &miscdev_test_fops,
+	};
+	struct miscdevice miscdyn_b = {
+		.name = "miscdyn_b",
+		.minor = MISC_DYNAMIC_MINOR,
+		.fops = &miscdev_test_fops,
+	};
+	int ret, minor_a;
+
+	ret = misc_register(&miscdyn_a);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+	KUNIT_EXPECT_TRUE(test, is_valid_dynamic_minor(miscdyn_a.minor));
+	minor_a = miscdyn_a.minor;
+	if (ret != 0)
+		return;
+	misc_deregister(&miscdyn_a);
+
+	ret = misc_register(&miscdyn_b);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, miscdyn_b.minor, minor_a);
+	if (ret != 0)
+		return;
+
+	ret = misc_register(&miscdyn_a);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+	KUNIT_EXPECT_TRUE(test, is_valid_dynamic_minor(miscdyn_a.minor));
+	KUNIT_EXPECT_NE(test, miscdyn_a.minor, miscdyn_b.minor);
+	if (ret == 0)
+		misc_deregister(&miscdyn_a);
+
+	misc_deregister(&miscdyn_b);
+}
+
 static struct kunit_case test_cases[] = {
 	KUNIT_CASE(kunit_static_minor),
 	KUNIT_CASE(kunit_misc_dynamic_minor),
@@ -611,6 +654,7 @@ static struct kunit_case test_cases[] = {
 	KUNIT_CASE(miscdev_test_duplicate_name),
 	KUNIT_CASE(miscdev_test_duplicate_name_leak),
 	KUNIT_CASE_PARAM(miscdev_test_duplicate_error, miscdev_gen_params),
+	KUNIT_CASE(miscdev_test_dynamic_reentry),
 	{}
 };
 

-- 
2.34.1

[PATCH v3 5/8] char: misc: Make registering miscdevice reentry who wants dynamic minor

[Zijun Hu]

From: Zijun Hu <zijun.hu@oss.qualcomm.com>

misc_deregister() frees dynamic minor @misc->minor but does not reset it
and cause kunit test case miscdev_test_dynamic_reentry() failure:

| Invalid fixed minor 257 for miscdevice 'miscdyn_a'
| #miscdev_test_dynamic_reentry: ASSERTION FAILED at misc_minor_kunit.c:639
| Expected ret == 0, but
| ret == -22 (0xffffffffffffffea)
| [FAILED] miscdev_test_dynamic_reentry

misc_register()/misc_deregister() are sometimes invoked by driver's
probe()/remove() separately, which has reentry requirement.

Fix by resetting @misc->minor to MISC_DYNAMIC_MINOR in misc_deregister()
as error handling of misc_register() does.

Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
---
 drivers/char/misc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index b8e66466184fa21fb66d968db7950e0b5669ac43..96ed343cf5c8509a09855020049a9af82a3ede95 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -288,6 +288,8 @@ void misc_deregister(struct miscdevice *misc)
 	list_del(&misc->list);
 	device_destroy(&misc_class, MKDEV(MISC_MAJOR, misc->minor));
 	misc_minor_free(misc->minor);
+	if (misc->minor > MISC_DYNAMIC_MINOR)
+		misc->minor = MISC_DYNAMIC_MINOR;
 	mutex_unlock(&misc_mtx);
 }
 EXPORT_SYMBOL(misc_deregister);

-- 
2.34.1

[PATCH v3 6/8] char: misc: Does not request module for miscdevice with dynamic minor

[Zijun Hu]

From: Zijun Hu <zijun.hu@oss.qualcomm.com>

misc_open() may request module for miscdevice with dynamic minor
which is meaningless since macro MODULE_ALIAS_MISCDEV() is not
applicable for dynamic minor.

Fix by only requesting module for miscdevice with fixed minor.

Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
---
 drivers/char/misc.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 96ed343cf5c8509a09855020049a9af82a3ede95..a0aae0fc792666a7bdc0ba00da9dc02ff9cead42 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -132,7 +132,8 @@ static int misc_open(struct inode *inode, struct file *file)
 		break;
 	}
 
-	if (!new_fops) {
+	/* Only request module for fixed minor code */
+	if (!new_fops && minor < MISC_DYNAMIC_MINOR) {
 		mutex_unlock(&misc_mtx);
 		request_module("char-major-%d-%d", MISC_MAJOR, minor);
 		mutex_lock(&misc_mtx);
@@ -144,10 +145,11 @@ static int misc_open(struct inode *inode, struct file *file)
 			new_fops = fops_get(iter->fops);
 			break;
 		}
-		if (!new_fops)
-			goto fail;
 	}
 
+	if (!new_fops)
+		goto fail;
+
 	/*
 	 * Place the miscdevice in the file's
 	 * private_data so it can be used by the

-- 
2.34.1

[PATCH v3 7/8] char: misc: Register fixed minor EISA_EEPROM_MINOR in linux/miscdevice.h

[Zijun Hu]

From: Zijun Hu <zijun.hu@oss.qualcomm.com>

Move fixed minor EISA_EEPROM_MINOR definition to linux/miscdevice.h.

Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
---
 drivers/parisc/eisa_eeprom.c | 2 --
 include/linux/miscdevice.h   | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/parisc/eisa_eeprom.c b/drivers/parisc/eisa_eeprom.c
index 443b15422fc179c7379082bb165ea2bb80785fb3..601cbb22574fd64b0c6be568442d5064d38a2c20 100644
--- a/drivers/parisc/eisa_eeprom.c
+++ b/drivers/parisc/eisa_eeprom.c
@@ -15,8 +15,6 @@
 #include <linux/uaccess.h>
 #include <asm/eisa_eeprom.h>
 
-#define 	EISA_EEPROM_MINOR 241
-
 static loff_t eisa_eeprom_llseek(struct file *file, loff_t offset, int origin)
 {
 	return fixed_size_llseek(file, offset, origin, HPEE_MAX_LENGTH);
diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h
index 565b88efeb23d02b7d91df1cd7df4bdcf2898224..7d0aa718499cc1867790e98eb6b84c1673091905 100644
--- a/include/linux/miscdevice.h
+++ b/include/linux/miscdevice.h
@@ -70,6 +70,7 @@
 #define UHID_MINOR		239
 #define USERIO_MINOR		240
 #define VHOST_VSOCK_MINOR	241
+#define EISA_EEPROM_MINOR	241
 #define RFKILL_MINOR		242
 
 /*

-- 
2.34.1

[PATCH v3 8/8] sparc: kernel: apc: Remove macro APC_MINOR definition

[Zijun Hu]

From: Zijun Hu <zijun.hu@oss.qualcomm.com>

Macro APC_MINOR is defined as MISC_DYNAMIC_MINOR to request dynamic
minor, but its name 'APC_MINOR' looks like fixed minor.

Remove the macro definition and directly use MISC_DYNAMIC_MINOR instead.

Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
---
 arch/sparc/kernel/apc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/sparc/kernel/apc.c b/arch/sparc/kernel/apc.c
index d44725d37e30f388bf8cf19d72baf720f94da084..849db20e7165cdf48d4d36cf770dd6aaaa191b41 100644
--- a/arch/sparc/kernel/apc.c
+++ b/arch/sparc/kernel/apc.c
@@ -28,7 +28,6 @@
  * #define APC_DEBUG_LED
  */
 
-#define APC_MINOR	MISC_DYNAMIC_MINOR
 #define APC_OBPNAME	"power-management"
 #define APC_DEVNAME "apc"
 
@@ -138,7 +137,7 @@ static const struct file_operations apc_fops = {
 	.llseek =		noop_llseek,
 };
 
-static struct miscdevice apc_miscdev = { APC_MINOR, APC_DEVNAME, &apc_fops };
+static struct miscdevice apc_miscdev = { MISC_DYNAMIC_MINOR, APC_DEVNAME, &apc_fops };
 
 static int apc_probe(struct platform_device *op)
 {

-- 
2.34.1

Re: [PATCH v3 2/8] char: misc: Adapt and add test cases for simple minor space division

[kernel test robot]

Hi Zijun,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 626e89412dfb88766d90d842af4d9ec432d8526f]

url:    https://github.com/intel-lab-lkp/linux/commits/Zijun-Hu/char-misc-Move-drivers-misc-misc_minor_kunit-c-to-drivers-char/20250702-202131
base:   626e89412dfb88766d90d842af4d9ec432d8526f
patch link:    https://lore.kernel.org/r/20250702-rfc_miscdev-v3-2-d8925de7893d%40oss.qualcomm.com
patch subject: [PATCH v3 2/8] char: misc: Adapt and add test cases for simple minor space division
config: powerpc64-randconfig-002-20250704 (https://download.01.org/0day-ci/archive/20250704/202507041717.ZONOYCp2-lkp@intel.com/config)
compiler: powerpc64-linux-gcc (GCC) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250704/202507041717.ZONOYCp2-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/202507041717.ZONOYCp2-lkp@intel.com/

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

WARNING: modpost: vmlinux: section mismatch in reference: hash_debug_pagealloc_alloc_slots+0x98 (section: .text) -> memblock_alloc_try_nid (section: .init.text)
>> WARNING: modpost: vmlinux: section mismatch in reference: test_cases+0x60 (section: .data) -> miscdev_test_invalid_input (section: .init.text)

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

Re: [PATCH v3 4/8] char: misc: Add a reentry test case about dynamic minor request

[kernel test robot]

Hi Zijun,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 626e89412dfb88766d90d842af4d9ec432d8526f]

url:    https://github.com/intel-lab-lkp/linux/commits/Zijun-Hu/char-misc-Move-drivers-misc-misc_minor_kunit-c-to-drivers-char/20250702-202131
base:   626e89412dfb88766d90d842af4d9ec432d8526f
patch link:    https://lore.kernel.org/r/20250702-rfc_miscdev-v3-4-d8925de7893d%40oss.qualcomm.com
patch subject: [PATCH v3 4/8] char: misc: Add a reentry test case about dynamic minor request
config: powerpc64-randconfig-002-20250704 (https://download.01.org/0day-ci/archive/20250704/202507042031.3gfceqb3-lkp@intel.com/config)
compiler: powerpc64-linux-gcc (GCC) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250704/202507042031.3gfceqb3-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/202507042031.3gfceqb3-lkp@intel.com/

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

WARNING: modpost: vmlinux: section mismatch in reference: hash_debug_pagealloc_alloc_slots+0x98 (section: .text) -> memblock_alloc_try_nid (section: .init.text)
WARNING: modpost: vmlinux: section mismatch in reference: test_cases+0x60 (section: .data) -> miscdev_test_invalid_input (section: .init.text)
>> WARNING: modpost: vmlinux: section mismatch in reference: test_cases+0x180 (section: .data) -> miscdev_test_dynamic_reentry (section: .init.text)

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