[kbuild-all] drivers/gpu/drm/bridge/analogix/anx7625.c:754:4: warning: Value stored to 'ret' is never read [clang-analyzer-deadcode.DeadStores]

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 614cb2751d3150850d459bee596c397f344a7936 commit: c489573b5b6ce6442ad4658d9d5ec77839b91622 Merge drm/drm-next into drm-misc-next date: 10 months ago config: x86_64-randconfig-c001-20210813 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 767496d19cb9a1fbba57ff08095faa161998ee36) 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 # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout c489573b5b6ce6442ad4658d9d5ec77839b91622 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 clang-analyzer If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; clang-analyzer warnings: (new ones prefixed by >>) ^ ~ net/9p/client.c:2093:2: note: Value stored to 'err' is never read err = 0; ^ ~ net/9p/client.c:2153:2: warning: Value stored to 'err' is never read [clang-analyzer-deadcode.DeadStores] err = 0; ^ ~ net/9p/client.c:2153:2: note: Value stored to 'err' is never read err = 0; ^ ~ net/9p/client.c:2184:2: warning: Value stored to 'err' is never read [clang-analyzer-deadcode.DeadStores] err = 0; ^ ~ net/9p/client.c:2184:2: note: Value stored to 'err' is never read err = 0; ^ ~ net/9p/client.c:2214:2: warning: Value stored to 'err' is never read [clang-analyzer-deadcode.DeadStores] err = 0; ^ ~ net/9p/client.c:2214:2: note: Value stored to 'err' is never read err = 0; ^ ~ net/9p/client.c:2247:2: warning: Value stored to 'err' is never read [clang-analyzer-deadcode.DeadStores] err = 0; ^ ~ net/9p/client.c:2247:2: note: Value stored to 'err' is never read err = 0; ^ ~ net/9p/client.c:2281:2: warning: Value stored to 'err' is never read [clang-analyzer-deadcode.DeadStores] err = 0; ^ ~ net/9p/client.c:2281:2: note: Value stored to 'err' is never read err = 0; ^ ~ Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 5 warnings generated. fs/jffs2/nodelist.c:600:9: warning: Access to field 'flash_offset' results in a dereference of a null pointer (loaded from variable 'ref') [clang-analyzer-core.NullDereference] while (ref->flash_offset != REF_EMPTY_NODE) { ^ fs/jffs2/nodelist.c:665:6: note: Assuming 'size' is not equal to 0 if (!size) ^~~~~ fs/jffs2/nodelist.c:665:2: note: Taking false branch if (!size) ^ fs/jffs2/nodelist.c:667:15: note: Assuming 'size' is <= field 'free_size' if (unlikely(size > jeb->free_size)) { ^ include/linux/compiler.h:78:42: note: expanded from macro 'unlikely' # define unlikely(x) __builtin_expect(!!(x), 0) ^ fs/jffs2/nodelist.c:667:2: note: Taking false branch if (unlikely(size > jeb->free_size)) { ^ fs/jffs2/nodelist.c:673:6: note: Assuming field 'last_node' is null if (jeb->last_node && ref_obsolete(jeb->last_node)) { ^~~~~~~~~~~~~~ fs/jffs2/nodelist.c:673:21: note: Left side of '&&' is false if (jeb->last_node && ref_obsolete(jeb->last_node)) { ^ fs/jffs2/nodelist.c:685:3: note: Calling 'jffs2_link_node_ref' jffs2_link_node_ref(c, jeb, ofs, size, NULL); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ fs/jffs2/nodelist.c:592:9: note: Assuming field 'allocated_refs' is not equal to 0 BUG_ON(!jeb->allocated_refs); ^ include/asm-generic/bug.h:63:45: note: expanded from macro 'BUG_ON' #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) ^~~~~~~~~ include/linux/compiler.h:78:42: note: expanded from macro 'unlikely' # define unlikely(x) __builtin_expect(!!(x), 0) ^ fs/jffs2/nodelist.c:592:2: note: Taking false branch BUG_ON(!jeb->allocated_refs); ^ include/asm-generic/bug.h:63:32: note: expanded from macro 'BUG_ON' #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) ^ fs/jffs2/nodelist.c:592:2: note: Loop condition is false. Exiting loop BUG_ON(!jeb->allocated_refs); ^ include/asm-generic/bug.h:63:27: note: expanded from macro 'BUG_ON' #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) ^ fs/jffs2/nodelist.c:595:2: note: Null pointer value stored to 'ref' ref = jeb->last_node; ^~~~~~~~~~~~~~~~~~~~ fs/jffs2/nodelist.c:600:9: note: Access to field 'flash_offset' results in a dereference of a null pointer (loaded from variable 'ref') while (ref->flash_offset != REF_EMPTY_NODE) { ^~~ Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 4 warnings generated. Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 4 warnings generated. Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 7 warnings generated. ret = sp_tx_rst_aux(ctx); ^ ~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/bridge/analogix/anx7625.c:754:4: note: Value stored to 'ret' is never read ret = sp_tx_rst_aux(ctx); ^ ~~~~~~~~~~~~~~~~~~ Suppressed 6 warnings (6 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 8 warnings generated. drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c:536:2: warning: Value stored to 'err' is never read [clang-analyzer-deadcode.DeadStores] err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2], ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c:536:2: note: Value stored to 'err' is never read err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P2], ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Suppressed 7 warnings (7 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 7 warnings generated. Suppressed 7 warnings (7 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 8 warnings generated. drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c:424:2: warning: Value stored to 'reg' is never read [clang-analyzer-deadcode.DeadStores] reg = readl(dp->reg_base + ANALOGIX_DP_SYS_CTL_3); ^ drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c:424:2: note: Value stored to 'reg' is never read Suppressed 7 warnings (6 in non-user code, 1 with check filters). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 5 warnings generated. Suppressed 5 warnings (5 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 6 warnings generated. Suppressed 6 warnings (6 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 11 warnings generated. Suppressed 11 warnings (11 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 11 warnings generated. Suppressed 11 warnings (11 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 11 warnings generated. Suppressed 11 warnings (11 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 5 warnings generated. drivers/iio/magnetometer/hmc5843_core.c:127:8: warning: Excessive padding in 'struct hmc5843_chip_info' (8 padding bytes, where 0 is optimal). Optimal fields order: channels, regval_to_samp_freq, regval_to_nanoscale, n_regval_to_samp_freq, n_regval_to_nanoscale, consider reordering the fields or adding explicit padding members [clang-analyzer-optin.performance.Padding] struct hmc5843_chip_info { ~~~~~~~^~~~~~~~~~~~~~~~~~~ drivers/iio/magnetometer/hmc5843_core.c:127:8: note: Excessive padding in 'struct hmc5843_chip_info' (8 padding bytes, where 0 is optimal). Optimal fields order: channels, regval_to_samp_freq, regval_to_nanoscale, n_regval_to_samp_freq, n_regval_to_nanoscale, consider reordering the fields or adding explicit padding members struct hmc5843_chip_info { ~~~~~~~^~~~~~~~~~~~~~~~~~~ Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 6 warnings generated. Suppressed 6 warnings (6 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 4 warnings generated. Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 7 warnings generated. drivers/iio/potentiometer/mcp41010.c:58:8: warning: Excessive padding in 'struct mcp41010_data' (86 padding bytes, where 22 is optimal). Optimal fields order: buf, value, spi, cfg, lock, consider reordering the fields or adding explicit padding members [clang-analyzer-optin.performance.Padding] struct mcp41010_data { ~~~~~~~^~~~~~~~~~~~~~~ drivers/iio/potentiometer/mcp41010.c:58:8: note: Excessive padding in 'struct mcp41010_data' (86 padding bytes, where 22 is optimal). Optimal fields order: buf, value, spi, cfg, lock, consider reordering the fields or adding explicit padding members struct mcp41010_data { ~~~~~~~^~~~~~~~~~~~~~~ Suppressed 6 warnings (6 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 4 warnings generated. Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 4 warnings generated. Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 6 warnings generated. Suppressed 6 warnings (6 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 4 warnings generated. Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 4 warnings generated. Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 4 warnings generated. Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. 4 warnings generated. Suppressed 4 warnings (4 in non-user code). Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well. vim +/ret +754 drivers/gpu/drm/bridge/analogix/anx7625.c 8bdfc5dae4e3ba Xin Ji 2020-09-18 720 8bdfc5dae4e3ba Xin Ji 2020-09-18 721 static int segments_edid_read(struct anx7625_data *ctx, 8bdfc5dae4e3ba Xin Ji 2020-09-18 722 u8 segment, u8 *buf, u8 offset) 8bdfc5dae4e3ba Xin Ji 2020-09-18 723 { 8bdfc5dae4e3ba Xin Ji 2020-09-18 724 u8 cnt; 8bdfc5dae4e3ba Xin Ji 2020-09-18 725 int ret; 8bdfc5dae4e3ba Xin Ji 2020-09-18 726 struct device *dev = &ctx->client->dev; 8bdfc5dae4e3ba Xin Ji 2020-09-18 727 8bdfc5dae4e3ba Xin Ji 2020-09-18 728 /* Write address only */ 8bdfc5dae4e3ba Xin Ji 2020-09-18 729 ret = anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, 8bdfc5dae4e3ba Xin Ji 2020-09-18 730 AP_AUX_ADDR_7_0, 0x30); 8bdfc5dae4e3ba Xin Ji 2020-09-18 731 ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, 8bdfc5dae4e3ba Xin Ji 2020-09-18 732 AP_AUX_COMMAND, 0x04); 8bdfc5dae4e3ba Xin Ji 2020-09-18 733 ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, 8bdfc5dae4e3ba Xin Ji 2020-09-18 734 AP_AUX_CTRL_STATUS, 8bdfc5dae4e3ba Xin Ji 2020-09-18 735 AP_AUX_CTRL_ADDRONLY | AP_AUX_CTRL_OP_EN); 8bdfc5dae4e3ba Xin Ji 2020-09-18 736 8bdfc5dae4e3ba Xin Ji 2020-09-18 737 ret |= wait_aux_op_finish(ctx); 8bdfc5dae4e3ba Xin Ji 2020-09-18 738 /* Write segment address */ 8bdfc5dae4e3ba Xin Ji 2020-09-18 739 ret |= sp_tx_aux_wr(ctx, segment); 8bdfc5dae4e3ba Xin Ji 2020-09-18 740 /* Data read */ 8bdfc5dae4e3ba Xin Ji 2020-09-18 741 ret |= anx7625_reg_write(ctx, ctx->i2c.rx_p0_client, 8bdfc5dae4e3ba Xin Ji 2020-09-18 742 AP_AUX_ADDR_7_0, 0x50); 8bdfc5dae4e3ba Xin Ji 2020-09-18 743 if (ret) { 8bdfc5dae4e3ba Xin Ji 2020-09-18 744 DRM_DEV_ERROR(dev, "IO error : aux initial fail.\n"); 8bdfc5dae4e3ba Xin Ji 2020-09-18 745 return ret; 8bdfc5dae4e3ba Xin Ji 2020-09-18 746 } 8bdfc5dae4e3ba Xin Ji 2020-09-18 747 8bdfc5dae4e3ba Xin Ji 2020-09-18 748 for (cnt = 0; cnt <= EDID_TRY_CNT; cnt++) { 8bdfc5dae4e3ba Xin Ji 2020-09-18 749 sp_tx_aux_wr(ctx, offset); 8bdfc5dae4e3ba Xin Ji 2020-09-18 750 /* Set I2C read com 0x01 mot = 0 and read 16 bytes */ 8bdfc5dae4e3ba Xin Ji 2020-09-18 751 ret = sp_tx_aux_rd(ctx, 0xf1); 8bdfc5dae4e3ba Xin Ji 2020-09-18 752 8bdfc5dae4e3ba Xin Ji 2020-09-18 753 if (ret) { 8bdfc5dae4e3ba Xin Ji 2020-09-18 @754 ret = sp_tx_rst_aux(ctx); 8bdfc5dae4e3ba Xin Ji 2020-09-18 755 DRM_DEV_ERROR(dev, "segment read fail, reset!\n"); 8bdfc5dae4e3ba Xin Ji 2020-09-18 756 } else { 8bdfc5dae4e3ba Xin Ji 2020-09-18 757 ret = anx7625_reg_block_read(ctx, ctx->i2c.rx_p0_client, 8bdfc5dae4e3ba Xin Ji 2020-09-18 758 AP_AUX_BUFF_START, 8bdfc5dae4e3ba Xin Ji 2020-09-18 759 MAX_DPCD_BUFFER_SIZE, buf); 8bdfc5dae4e3ba Xin Ji 2020-09-18 760 if (ret > 0) 8bdfc5dae4e3ba Xin Ji 2020-09-18 761 break; 8bdfc5dae4e3ba Xin Ji 2020-09-18 762 } 8bdfc5dae4e3ba Xin Ji 2020-09-18 763 } 8bdfc5dae4e3ba Xin Ji 2020-09-18 764 8bdfc5dae4e3ba Xin Ji 2020-09-18 765 if (cnt > EDID_TRY_CNT) 8bdfc5dae4e3ba Xin Ji 2020-09-18 766 return -EIO; 8bdfc5dae4e3ba Xin Ji 2020-09-18 767 8bdfc5dae4e3ba Xin Ji 2020-09-18 768 return 0; 8bdfc5dae4e3ba Xin Ji 2020-09-18 769 } 8bdfc5dae4e3ba Xin Ji 2020-09-18 770 :::::: The code at line 754 was first introduced by commit :::::: 8bdfc5dae4e3ba4d99dfb430ef43249e5f1b7730 drm/bridge: anx7625: Add anx7625 MIPI DSI/DPI to DP :::::: TO: Xin Ji <xji(a)analogixsemi.com&gt; :::::: CC: Sam Ravnborg <sam(a)ravnborg.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org