diff mbox series

[06/12] drm/client: Constify modes

Message ID 20240404203336.10454-7-ville.syrjala@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series drm/client: Use after free and debug improvements | expand

Commit Message

Ville Syrjala April 4, 2024, 8:33 p.m. UTC 
From: Ville Syrjälä <ville.syrjala@linux.intel.com>

The modes used by the client code live on the connectors' mode
lists, which are not owned by the client code, and thus it has
no business modifying the modes. Mark the modes const to make
that fact abundantly clear.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/drm_client_modeset.c | 36 +++++++++++++++-------------
 1 file changed, 19 insertions(+), 17 deletions(-)

Comments

kernel test robot April 5, 2024, 7:01 a.m. UTC | #1 
Hi Ville,

kernel test robot noticed the following build warnings:

[auto build test WARNING on drm-misc/drm-misc-next]
[also build test WARNING on drm-intel/for-linux-next drm-intel/for-linux-next-fixes drm-tip/drm-tip linus/master v6.9-rc2 next-20240405]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ville-Syrjala/drm-client-Fully-protect-modes-with-dev-mode_config-mutex/20240405-043540
base:   git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
patch link:    https://lore.kernel.org/r/20240404203336.10454-7-ville.syrjala%40linux.intel.com
patch subject: [PATCH 06/12] drm/client: Constify modes
config: i386-randconfig-012-20240405 (https://download.01.org/0day-ci/archive/20240405/202404051422.BpYVK6TP-lkp@intel.com/config)
compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240405/202404051422.BpYVK6TP-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/202404051422.BpYVK6TP-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/gpu/drm/drm_client_modeset.c:1241:0:
   drivers/gpu/drm/tests/drm_client_modeset_test.c: In function 'drm_test_pick_cmdline_res_1920_1080_60':
>> drivers/gpu/drm/tests/drm_client_modeset_test.c:108:7: warning: assignment discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
     mode = drm_connector_pick_cmdline_mode(connector);
          ^


vim +/const +108 drivers/gpu/drm/tests/drm_client_modeset_test.c

8fc0380f6ba7e9 Maxime Ripard 2022-11-14   84  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   85  static void drm_test_pick_cmdline_res_1920_1080_60(struct kunit *test)
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   86  {
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   87  	struct drm_client_modeset_test_priv *priv = test->priv;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   88  	struct drm_device *drm = priv->drm;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   89  	struct drm_connector *connector = &priv->connector;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   90  	struct drm_cmdline_mode *cmdline_mode = &connector->cmdline_mode;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   91  	struct drm_display_mode *expected_mode, *mode;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   92  	const char *cmdline = "1920x1080@60";
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   93  	int ret;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   94  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   95  	expected_mode = drm_mode_find_dmt(priv->drm, 1920, 1080, 60, false);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   96  	KUNIT_ASSERT_NOT_NULL(test, expected_mode);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   97  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   98  	KUNIT_ASSERT_TRUE(test,
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   99  			  drm_mode_parse_command_line_for_connector(cmdline,
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  100  								    connector,
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  101  								    cmdline_mode));
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  102  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  103  	mutex_lock(&drm->mode_config.mutex);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  104  	ret = drm_helper_probe_single_connector_modes(connector, 1920, 1080);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  105  	mutex_unlock(&drm->mode_config.mutex);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  106  	KUNIT_ASSERT_GT(test, ret, 0);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  107  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14 @108  	mode = drm_connector_pick_cmdline_mode(connector);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  109  	KUNIT_ASSERT_NOT_NULL(test, mode);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  110  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  111  	KUNIT_EXPECT_TRUE(test, drm_mode_equal(expected_mode, mode));
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  112  }
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  113
kernel test robot April 6, 2024, 9:59 p.m. UTC | #2 
Hi Ville,

kernel test robot noticed the following build errors:

[auto build test ERROR on drm-misc/drm-misc-next]
[also build test ERROR on drm-intel/for-linux-next drm-intel/for-linux-next-fixes drm-tip/drm-tip linus/master v6.9-rc2 next-20240405]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ville-Syrjala/drm-client-Fully-protect-modes-with-dev-mode_config-mutex/20240405-043540
base:   git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
patch link:    https://lore.kernel.org/r/20240404203336.10454-7-ville.syrjala%40linux.intel.com
patch subject: [PATCH 06/12] drm/client: Constify modes
config: hexagon-allyesconfig (https://download.01.org/0day-ci/archive/20240407/202404070528.NgbaKKH3-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project 546dc2245ffc4cccd0b05b58b7a5955e355a3b27)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240407/202404070528.NgbaKKH3-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/202404070528.NgbaKKH3-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from drivers/gpu/drm/drm_client_modeset.c:16:
   In file included from include/drm/drm_atomic.h:31:
   In file included from include/drm/drm_crtc.h:32:
   In file included from include/drm/drm_modes.h:33:
   In file included from include/drm/drm_connector.h:32:
   In file included from include/drm/drm_util.h:35:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:547:31: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from drivers/gpu/drm/drm_client_modeset.c:16:
   In file included from include/drm/drm_atomic.h:31:
   In file included from include/drm/drm_crtc.h:32:
   In file included from include/drm/drm_modes.h:33:
   In file included from include/drm/drm_connector.h:32:
   In file included from include/drm/drm_util.h:35:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:573:61: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from drivers/gpu/drm/drm_client_modeset.c:16:
   In file included from include/drm/drm_atomic.h:31:
   In file included from include/drm/drm_crtc.h:32:
   In file included from include/drm/drm_modes.h:33:
   In file included from include/drm/drm_connector.h:32:
   In file included from include/drm/drm_util.h:35:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:328:
   include/asm-generic/io.h:584:33: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   In file included from drivers/gpu/drm/drm_client_modeset.c:16:
   In file included from include/drm/drm_atomic.h:31:
   In file included from include/drm/drm_crtc.h:32:
   In file included from include/drm/drm_modes.h:33:
   In file included from include/drm/drm_connector.h:32:
   In file included from include/drm/drm_util.h:36:
   In file included from include/linux/kgdb.h:19:
   In file included from include/linux/kprobes.h:28:
   In file included from include/linux/ftrace.h:13:
   In file included from include/linux/kallsyms.h:13:
   In file included from include/linux/mm.h:2208:
   include/linux/vmstat.h:522:36: error: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Werror,-Wenum-enum-conversion]
     522 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   In file included from drivers/gpu/drm/drm_client_modeset.c:1241:
>> drivers/gpu/drm/tests/drm_client_modeset_test.c:108:7: error: assigning to 'struct drm_display_mode *' from 'const struct drm_display_mode *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
     108 |         mode = drm_connector_pick_cmdline_mode(connector);
         |              ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   8 errors generated.


vim +108 drivers/gpu/drm/tests/drm_client_modeset_test.c

8fc0380f6ba7e9 Maxime Ripard 2022-11-14   84  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   85  static void drm_test_pick_cmdline_res_1920_1080_60(struct kunit *test)
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   86  {
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   87  	struct drm_client_modeset_test_priv *priv = test->priv;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   88  	struct drm_device *drm = priv->drm;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   89  	struct drm_connector *connector = &priv->connector;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   90  	struct drm_cmdline_mode *cmdline_mode = &connector->cmdline_mode;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   91  	struct drm_display_mode *expected_mode, *mode;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   92  	const char *cmdline = "1920x1080@60";
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   93  	int ret;
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   94  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   95  	expected_mode = drm_mode_find_dmt(priv->drm, 1920, 1080, 60, false);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   96  	KUNIT_ASSERT_NOT_NULL(test, expected_mode);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   97  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   98  	KUNIT_ASSERT_TRUE(test,
8fc0380f6ba7e9 Maxime Ripard 2022-11-14   99  			  drm_mode_parse_command_line_for_connector(cmdline,
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  100  								    connector,
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  101  								    cmdline_mode));
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  102  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  103  	mutex_lock(&drm->mode_config.mutex);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  104  	ret = drm_helper_probe_single_connector_modes(connector, 1920, 1080);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  105  	mutex_unlock(&drm->mode_config.mutex);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  106  	KUNIT_ASSERT_GT(test, ret, 0);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  107  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14 @108  	mode = drm_connector_pick_cmdline_mode(connector);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  109  	KUNIT_ASSERT_NOT_NULL(test, mode);
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  110  
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  111  	KUNIT_EXPECT_TRUE(test, drm_mode_equal(expected_mode, mode));
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  112  }
8fc0380f6ba7e9 Maxime Ripard 2022-11-14  113
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
index cf1de06f99aa..384a9f8227a0 100644
--- a/drivers/gpu/drm/drm_client_modeset.c
+++ b/drivers/gpu/drm/drm_client_modeset.c
@@ -117,10 +117,10 @@  drm_client_find_modeset(struct drm_client_dev *client, struct drm_crtc *crtc)
 	return NULL;
 }
 
-static struct drm_display_mode *
+static const struct drm_display_mode *
 drm_connector_get_tiled_mode(struct drm_connector *connector)
 {
-	struct drm_display_mode *mode;
+	const struct drm_display_mode *mode;
 
 	list_for_each_entry(mode, &connector->modes, head) {
 		if (mode->hdisplay == connector->tile_h_size &&
@@ -130,10 +130,10 @@  drm_connector_get_tiled_mode(struct drm_connector *connector)
 	return NULL;
 }
 
-static struct drm_display_mode *
+static const struct drm_display_mode *
 drm_connector_fallback_non_tiled_mode(struct drm_connector *connector)
 {
-	struct drm_display_mode *mode;
+	const struct drm_display_mode *mode;
 
 	list_for_each_entry(mode, &connector->modes, head) {
 		if (mode->hdisplay == connector->tile_h_size &&
@@ -144,10 +144,10 @@  drm_connector_fallback_non_tiled_mode(struct drm_connector *connector)
 	return NULL;
 }
 
-static struct drm_display_mode *
+static const struct drm_display_mode *
 drm_connector_preferred_mode(struct drm_connector *connector, int width, int height)
 {
-	struct drm_display_mode *mode;
+	const struct drm_display_mode *mode;
 
 	list_for_each_entry(mode, &connector->modes, head) {
 		if (mode->hdisplay > width ||
@@ -159,10 +159,11 @@  drm_connector_preferred_mode(struct drm_connector *connector, int width, int hei
 	return NULL;
 }
 
-static struct drm_display_mode *drm_connector_pick_cmdline_mode(struct drm_connector *connector)
+static const struct drm_display_mode *
+drm_connector_pick_cmdline_mode(struct drm_connector *connector)
 {
-	struct drm_cmdline_mode *cmdline_mode;
-	struct drm_display_mode *mode;
+	const struct drm_cmdline_mode *cmdline_mode;
+	const struct drm_display_mode *mode;
 	bool prefer_non_interlace;
 
 	/*
@@ -258,13 +259,14 @@  static void drm_client_connectors_enabled(struct drm_connector **connectors,
 static bool drm_client_target_cloned(struct drm_device *dev,
 				     struct drm_connector **connectors,
 				     unsigned int connector_count,
-				     struct drm_display_mode **modes,
+				     const struct drm_display_mode **modes,
 				     struct drm_client_offset *offsets,
 				     bool *enabled, int width, int height)
 {
 	int count, i, j;
 	bool can_clone = false;
-	struct drm_display_mode *dmt_mode, *mode;
+	const struct drm_display_mode *mode;
+	struct drm_display_mode *dmt_mode;
 
 	/* only contemplate cloning in the single crtc case */
 	if (dev->mode_config.num_crtc > 1)
@@ -342,7 +344,7 @@  static bool drm_client_target_cloned(struct drm_device *dev,
 
 static int drm_client_get_tile_offsets(struct drm_connector **connectors,
 				       unsigned int connector_count,
-				       struct drm_display_mode **modes,
+				       const struct drm_display_mode **modes,
 				       struct drm_client_offset *offsets,
 				       int idx,
 				       int h_idx, int v_idx)
@@ -375,7 +377,7 @@  static int drm_client_get_tile_offsets(struct drm_connector **connectors,
 
 static bool drm_client_target_preferred(struct drm_connector **connectors,
 					unsigned int connector_count,
-					struct drm_display_mode **modes,
+					const struct drm_display_mode **modes,
 					struct drm_client_offset *offsets,
 					bool *enabled, int width, int height)
 {
@@ -492,7 +494,7 @@  static int drm_client_pick_crtcs(struct drm_client_dev *client,
 				 struct drm_connector **connectors,
 				 unsigned int connector_count,
 				 struct drm_crtc **best_crtcs,
-				 struct drm_display_mode **modes,
+				 const struct drm_display_mode **modes,
 				 int n, int width, int height)
 {
 	struct drm_device *dev = client->dev;
@@ -567,7 +569,7 @@  static bool drm_client_firmware_config(struct drm_client_dev *client,
 				       struct drm_connector **connectors,
 				       unsigned int connector_count,
 				       struct drm_crtc **crtcs,
-				       struct drm_display_mode **modes,
+				       const struct drm_display_mode **modes,
 				       struct drm_client_offset *offsets,
 				       bool *enabled, int width, int height)
 {
@@ -772,7 +774,7 @@  int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width,
 	struct drm_client_offset *offsets;
 	unsigned int connector_count = 0;
 	/* points to modes protected by mode_config.mutex */
-	struct drm_display_mode **modes;
+	const struct drm_display_mode **modes;
 	struct drm_crtc **crtcs;
 	int i, ret = 0;
 	bool *enabled;
@@ -844,7 +846,7 @@  int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width,
 	drm_client_modeset_release(client);
 
 	for (i = 0; i < connector_count; i++) {
-		struct drm_display_mode *mode = modes[i];
+		const struct drm_display_mode *mode = modes[i];
 		struct drm_crtc *crtc = crtcs[i];
 		struct drm_client_offset *offset = &offsets[i];