drivers/gpu/drm/ast/ast_mode.c:1232:3: warning: Use of memory after it is freed [clang-analyzer-unix.Malloc]
From: kernel test robot
Date: Tue Jan 18 2022 - 02:33:29 EST
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: fb3b0673b7d5b477ed104949450cd511337ba3c6
commit: 55dc449a7c60d3df5a8f0b71bbae9d5173c864f5 drm/ast: Handle failed I2C initialization gracefully
date: 4 weeks ago
config: riscv-randconfig-c006-20220113 (https://download.01.org/0day-ci/archive/20220114/202201141416.VfNXpsi5-lkp@xxxxxxxxx/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project d1021978b8e7e35dcc30201ca1731d64b5a602a8)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv64-linux-gnu
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=55dc449a7c60d3df5a8f0b71bbae9d5173c864f5
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 55dc449a7c60d3df5a8f0b71bbae9d5173c864f5
# save the config file to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv clang-analyzer
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
clang-analyzer warnings: (new ones prefixed by >>)
>> drivers/gpu/drm/ast/ast_mode.c:1232:3: warning: Use of memory after it is freed [clang-analyzer-unix.Malloc]
drm_connector_update_edid_property(&ast_connector->base, edid);
^ ~~~~
drivers/gpu/drm/ast/ast_mode.c:1217:6: note: Assuming field 'tx_chip_type' is equal to AST_TX_DP501
if (ast->tx_chip_type == AST_TX_DP501) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/ast/ast_mode.c:1217:2: note: Taking true branch
if (ast->tx_chip_type == AST_TX_DP501) {
^
drivers/gpu/drm/ast/ast_mode.c:1220:7: note: Assuming 'edid' is non-null
if (!edid)
^~~~~
drivers/gpu/drm/ast/ast_mode.c:1220:3: note: Taking false branch
if (!edid)
^
drivers/gpu/drm/ast/ast_mode.c:1224:7: note: Assuming 'flags' is false
if (flags)
^~~~~
drivers/gpu/drm/ast/ast_mode.c:1224:3: note: Taking false branch
if (flags)
^
drivers/gpu/drm/ast/ast_mode.c:1227:4: note: Memory is released
kfree(edid);
^~~~~~~~~~~
drivers/gpu/drm/ast/ast_mode.c:1229:7: note: 'flags' is false
if (!flags && ast_connector->i2c)
^~~~~
drivers/gpu/drm/ast/ast_mode.c:1229:6: note: Left side of '&&' is true
if (!flags && ast_connector->i2c)
^
drivers/gpu/drm/ast/ast_mode.c:1229:16: note: Assuming field 'i2c' is null
if (!flags && ast_connector->i2c)
^~~~~~~~~~~~~~~~~~
drivers/gpu/drm/ast/ast_mode.c:1229:2: note: Taking false branch
if (!flags && ast_connector->i2c)
^
drivers/gpu/drm/ast/ast_mode.c:1231:6: note: 'edid' is non-null
if (edid) {
^~~~
drivers/gpu/drm/ast/ast_mode.c:1231:2: note: Taking true branch
if (edid) {
^
drivers/gpu/drm/ast/ast_mode.c:1232:3: note: Use of memory after it is freed
drm_connector_update_edid_property(&ast_connector->base, edid);
^ ~~~~
vim +1232 drivers/gpu/drm/ast/ast_mode.c
312fec1405dd54 Dave Airlie 2012-02-29 1204
4961eb60f14553 Thomas Zimmermann 2019-11-07 1205 /*
4961eb60f14553 Thomas Zimmermann 2019-11-07 1206 * Connector
4961eb60f14553 Thomas Zimmermann 2019-11-07 1207 */
4961eb60f14553 Thomas Zimmermann 2019-11-07 1208
312fec1405dd54 Dave Airlie 2012-02-29 1209 static int ast_get_modes(struct drm_connector *connector)
312fec1405dd54 Dave Airlie 2012-02-29 1210 {
312fec1405dd54 Dave Airlie 2012-02-29 1211 struct ast_connector *ast_connector = to_ast_connector(connector);
fa7dbd7688849d Thomas Zimmermann 2020-06-17 1212 struct ast_private *ast = to_ast_private(connector->dev);
55dc449a7c60d3 Thomas Zimmermann 2021-12-06 1213 struct edid *edid = NULL;
83c6620bae3f14 Dave Airlie 2014-03-28 1214 bool flags = false;
55dc449a7c60d3 Thomas Zimmermann 2021-12-06 1215 int ret;
6c9bd4432b2527 Gregory Williams 2021-07-30 1216
83c6620bae3f14 Dave Airlie 2014-03-28 1217 if (ast->tx_chip_type == AST_TX_DP501) {
83c6620bae3f14 Dave Airlie 2014-03-28 1218 ast->dp501_maxclk = 0xff;
83c6620bae3f14 Dave Airlie 2014-03-28 1219 edid = kmalloc(128, GFP_KERNEL);
83c6620bae3f14 Dave Airlie 2014-03-28 1220 if (!edid)
83c6620bae3f14 Dave Airlie 2014-03-28 1221 return -ENOMEM;
312fec1405dd54 Dave Airlie 2012-02-29 1222
83c6620bae3f14 Dave Airlie 2014-03-28 1223 flags = ast_dp501_read_edid(connector->dev, (u8 *)edid);
83c6620bae3f14 Dave Airlie 2014-03-28 1224 if (flags)
83c6620bae3f14 Dave Airlie 2014-03-28 1225 ast->dp501_maxclk = ast_get_dp501_max_clk(connector->dev);
83c6620bae3f14 Dave Airlie 2014-03-28 1226 else
83c6620bae3f14 Dave Airlie 2014-03-28 1227 kfree(edid);
83c6620bae3f14 Dave Airlie 2014-03-28 1228 }
55dc449a7c60d3 Thomas Zimmermann 2021-12-06 1229 if (!flags && ast_connector->i2c)
312fec1405dd54 Dave Airlie 2012-02-29 1230 edid = drm_get_edid(connector, &ast_connector->i2c->adapter);
312fec1405dd54 Dave Airlie 2012-02-29 1231 if (edid) {
c555f02371c338 Daniel Vetter 2018-07-09 @1232 drm_connector_update_edid_property(&ast_connector->base, edid);
312fec1405dd54 Dave Airlie 2012-02-29 1233 ret = drm_add_edid_modes(connector, edid);
993dcb05e47e35 Jani Nikula 2012-08-15 1234 kfree(edid);
312fec1405dd54 Dave Airlie 2012-02-29 1235 return ret;
6c9bd4432b2527 Gregory Williams 2021-07-30 1236 }
c555f02371c338 Daniel Vetter 2018-07-09 1237 drm_connector_update_edid_property(&ast_connector->base, NULL);
312fec1405dd54 Dave Airlie 2012-02-29 1238 return 0;
312fec1405dd54 Dave Airlie 2012-02-29 1239 }
312fec1405dd54 Dave Airlie 2012-02-29 1240
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