Folks, after picking up Josh's objtool updates I gave clang a test ride again.
clan is built with https://github.com/ClangBuiltLinux/tc-build.git That's using the llvm master branch. top commit is: 0c99d19470b ("[OPENMP]Fix sharing of threadprivate variables with TLS support.") I merged git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git core/urgent into the tip of Linus tree to pick up the latest objtool changes. Here are the results for different configs: 1) defconfig objtool warnings: drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x88: redundant UACCESS disable 2) debian distro config objtool warnings: drivers/gpu/drm/amd/amdgpu/atom.o: warning: objtool: atom_op_move() falls through to next function atom_op_and() drivers/infiniband/hw/hfi1/platform.o: warning: objtool: tune_serdes() falls through to next function apply_tx_lanes() drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x86: redundant UACCESS disable drivers/gpu/drm/radeon/evergreen_cs.o: warning: objtool: evergreen_cs_parse() falls through to next function evergreen_dma_cs_parse() Build fails with: clang-10: error: unknown argument: '-mpreferred-stack-boundary=4' make[5]: *** [linux/scripts/Makefile.build:279: drivers/gpu/drm/amd/amdgpu/../display/dc/dcn20/dcn20_resource.o] Error 1 3) allmodconfig: objtool warnings: arch/x86/kernel/signal.o: warning: objtool: x32_setup_rt_frame()+0x255: call to memset() with UACCESS enabled arch/x86/kernel/signal.o: warning: objtool: __setup_rt_frame()+0x254: call to memset() with UACCESS enabled arch/x86/ia32/ia32_signal.o: warning: objtool: ia32_setup_rt_frame()+0x247: call to memset() with UACCESS enabled mm/kasan/common.o: warning: objtool: kasan_report()+0x52: call to __stack_chk_fail() with UACCESS enabled drivers/ata/sata_dwc_460ex.o: warning: objtool: sata_dwc_bmdma_start_by_tag()+0x3a0: can't find switch jump table lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0x88: call to memset() with UACCESS enabled lib/ubsan.o: warning: objtool: ubsan_type_mismatch_common()+0x610: call to __stack_chk_fail() with UACCESS enabled lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0x88: call to memset() with UACCESS enabled drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x56: redundant UACCESS disable Build fails with: ERROR: "__compiletime_assert_2801" [drivers/net/wireless/intel/iwlwifi/iwlwifi.ko] undefined! ERROR: "__compiletime_assert_2446" [drivers/net/wireless/intel/iwlwifi/iwlwifi.ko] undefined! ERROR: "__compiletime_assert_2452" [drivers/net/wireless/intel/iwlwifi/iwlwifi.ko] undefined! ERROR: "__compiletime_assert_2790" [drivers/net/wireless/intel/iwlwifi/iwlwifi.ko] undefined! This also emits a boatload of warnings like this: linux/fs/nfs/dir.c:451:34: warning: variable 'wq' is uninitialized when used within its own initialization [-Wuninitialized] DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); ^~ linux/include/linux/wait.h:74:63: note: expanded from macro 'DECLARE_WAIT_QUEUE_HEAD_ONSTACK' struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name) ~~~~ ^~~~ linux/include/linux/wait.h:72:33: note: expanded from macro '__WAIT_QUEUE_HEAD_INIT_ONSTACK' ({ init_waitqueue_head(&name); name; }) Thanks, tglx
