Hi Alexei, I love your patch! Perhaps something to improve: [auto build test WARNING on bpf-next/master] url: https://github.com/0day-ci/linux/commits/Alexei-Starovoitov/bpf-Light-ske... base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: mips-buildonly-randconfig-r001-20220208 (https://download.01.org/0day-ci/archive/20220209/202202090005.4wGpcCXF-lk...) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project e8bff9ae54a55b4dbfeb6ba55f723abbd81bf494) 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 mips cross compiling tool for clang build # apt-get install binutils-mips-linux-gnu # https://github.com/0day-ci/linux/commit/cf2c9222692d0cb93d17ab3ff9f972b40... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Alexei-Starovoitov/bpf-Light-skeleton-for-the-kernel/20220205-071811 git checkout cf2c9222692d0cb93d17ab3ff9f972b40a0b7864 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash kernel/bpf/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): struct bpf_prog ^ fatal error: error in backend: Nested variants found in inline asm string: ' .set push .set mips64r2 .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/atomic.h", .line = 156, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif 1: ll $1, $2 # atomic_sub_return subu $0, $1, $3 sc $0, $2 beqz $0, 1b subu $0, $1, $3 .set pop ' PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script. Stack dump: 0. Program arguments: clang -Wp,-MMD,kernel/bpf/.syscall.o.d -nostdinc -Iarch/mips/include -I./arch/mips/include/generated -Iinclude -I./include -Iarch/mips/include/uapi -I./arch/mips/include/generated/uapi -Iinclude/uapi -I./include/generated/uapi -include include/linux/compiler-version.h -include include/linux/kconfig.h -include include/linux/compiler_types.h -D__KERNEL__ -DVMLINUX_LOAD_ADDRESS=0xffffffff80060000 -DLINKER_LOAD_ADDRESS=0x80060000 -DDATAOFFSET=0 -Qunused-arguments -fmacro-prefix-map== -DKBUILD_EXTRA_WARN1 -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE -Werror=implicit-function-declaration -Werror=implicit-int -Werror=return-type -Wno-format-security -std=gnu89 --target=mips-linux -fintegrated-as -Werror=unknown-warning-option -Werror=ignored-optimization-argument -mno-check-zero-division -mabi=32 -G 0 -mno-abicalls -fno-pic -pipe -msoft-float -DGAS_HAS_SET_HARDFLOAT -Wa,-msoft-float -ffreestanding -EB -fno-stack-check -march=mips32r2 -Wa,--trap -DTOOLCHAIN_SUPPORTS_VIRT -Iarch/mips/include/asm/mach-ath79 -Iarch/mips/include/asm/mach-generic -fno-asynchronous-unwind-tables -fno-delete-null-pointer-checks -Wno-frame-address -Wno-address-of-packed-member -O2 -Wframe-larger-than=1024 -fno-stack-protector -Wimplicit-fallthrough -Wno-gnu -mno-global-merge -Wno-unused-but-set-variable -Wno-unused-const-variable -ftrivial-auto-var-init=zero -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang -fno-stack-clash-protection -pg -Wdeclaration-after-statement -Wvla -Wno-pointer-sign -Wcast-function-type -Wno-array-bounds -fno-strict-overflow -fno-stack-check -Werror=date-time -Werror=incompatible-pointer-types -Wextra -Wunused -Wno-unused-parameter -Wmissing-declarations -Wmissing-format-attribute -Wmissing-prototypes -Wold-style-definition -Wmissing-include-dirs -Wunused-but-set-variable -Wunused-const-variable -Wno-missing-field-initializers -Wno-sign-compare -Wno-type-limits -I kernel/bpf -I ./kernel/bpf -ffunction-sections -fdata-sections -DKBUILD_MODFILE="kernel/bpf/syscall" -DKBUILD_BASENAME="syscall" -DKBUILD_MODNAME="syscall" -D__KBUILD_MODNAME=kmod_syscall -c -o kernel/bpf/syscall.o kernel/bpf/syscall.c 1. <eof> parser at end of file 2. Code generation 3. Running pass 'Function Pass Manager' on module 'kernel/bpf/syscall.c'. 4. Running pass 'Mips Assembly Printer' on function '@bpf_map_free_deferred' #0 0x0000564a3997132f Signals.cpp:0:0 #1 0x0000564a3996f20c llvm::sys::CleanupOnSignal(unsigned long) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x346420c) #2 0x0000564a398af687 llvm::CrashRecoveryContext::HandleExit(int) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x33a4687) #3 0x0000564a399678be llvm::sys::Process::Exit(int, bool) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x345c8be) #4 0x0000564a375aee3b (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x10a3e3b) #5 0x0000564a398b613c llvm::report_fatal_error(llvm::Twine const&, bool) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x33ab13c) #6 0x0000564a3a5a55a0 llvm::AsmPrinter::emitInlineAsm(llvm::MachineInstr const (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x409a5a0) #7 0x0000564a3a5a14d4 llvm::AsmPrinter::emitFunctionBody() (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x40964d4) #8 0x0000564a38016b57 llvm::MipsAsmPrinter::runOnMachineFunction(llvm::MachineFunction&) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x1b0bb57) #9 0x0000564a38cc85dd llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.53) MachineFunctionPass.cpp:0:0 #10 0x0000564a39103d97 llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x2bf8d97) #11 0x0000564a39103f11 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x2bf8f11) #12 0x0000564a39104a8f llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x2bf9a8f) #13 0x0000564a39c88ef7 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream> >) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x377def7) #14 0x0000564a3a8bdb63 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x43b2b63) #15 0x0000564a3b392e29 clang::ParseAST(clang::Sema&, bool, bool) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x4e87e29) #16 0x0000564a3a8bc99f clang::CodeGenAction::ExecuteAction() (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x43b199f) #17 0x0000564a3a2bb1e1 clang::FrontendAction::Execute() (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x3db01e1) #18 0x0000564a3a25211a clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x3d4711a) #19 0x0000564a3a37f85b (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x3e7485b) #20 0x0000564a375b03ec cc1_main(llvm::ArrayRef<char char (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x10a53ec) #21 0x0000564a375ad0bb ExecuteCC1Tool(llvm::SmallVectorImpl<char driver.cpp:0:0 #22 0x0000564a3a0e9c85 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> const::'lambda'()>(long) Job.cpp:0:0 #23 0x0000564a398af543 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x33a4543) #24 0x0000564a3a0ea57e clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> const (.part.216) Job.cpp:0:0 #25 0x0000564a3a0bf177 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x3bb4177) #26 0x0000564a3a0bfb57 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command >&) const (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x3bb4b57) #27 0x0000564a3a0c91e9 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command >&) (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x3bbe1e9) #28 0x0000564a374d626f main (/opt/cross/clang-e8bff9ae54/bin/clang-15+0xfcb26f) #29 0x00007fa3ac551d0a __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x26d0a) #30 0x0000564a375acbda _start (/opt/cross/clang-e8bff9ae54/bin/clang-15+0x10a1bda) clang-15: error: clang frontend command failed with exit code 70 (use -v to see invocation) clang version 15.0.0 (git://gitmirror/llvm_project e8bff9ae54a55b4dbfeb6ba55f723abbd81bf494) Target: mips-unknown-linux Thread model: posix InstalledDir: /opt/cross/clang-e8bff9ae54/bin clang-15: note: diagnostic msg: Makefile arch include kernel nr_bisected scripts source usr vim +/prog +4762 kernel/bpf/syscall.c 4759 4760 BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size) 4761 { 4763 4764 switch (cmd) { 4765 case BPF_MAP_CREATE: 4766 case BPF_MAP_UPDATE_ELEM: 4767 case BPF_MAP_FREEZE: 4768 case BPF_PROG_LOAD: 4769 case BPF_BTF_LOAD: 4770 case BPF_LINK_CREATE: 4771 case BPF_RAW_TRACEPOINT_OPEN: 4772 break; 4773 #ifdef CONFIG_BPF_JIT /* __bpf_prog_enter_sleepable used by trampoline and JIT */ 4774 case BPF_PROG_TEST_RUN: 4775 if (attr->test.data_in || attr->test.data_out || 4776 attr->test.ctx_out || attr->test.duration || 4777 attr->test.repeat || attr->test.flags) 4778 return -EINVAL; 4779 4780 prog = bpf_prog_get_type(attr->test.prog_fd, BPF_PROG_TYPE_SYSCALL); 4781 if (IS_ERR(prog)) 4782 return PTR_ERR(prog); 4783 4784 if (attr->test.ctx_size_in < prog->aux->max_ctx_offset || 4785 attr->test.ctx_size_in > U16_MAX) { 4786 bpf_prog_put(prog); 4787 return -EINVAL; 4788 } 4789 4790 if (!__bpf_prog_enter_sleepable(prog)) { 4791 /* recursion detected */ 4792 bpf_prog_put(prog); 4793 return -EBUSY; 4794 } 4795 attr->test.retval = bpf_prog_run(prog, (void *) (long) attr->test.ctx_in); 4796 __bpf_prog_exit_sleepable(prog, 0 /* bpf_prog_run does runtime stats */); 4797 bpf_prog_put(prog); 4798 return 0; 4799 #endif 4800 default: 4801 return -EINVAL; 4802 } 4803 return __sys_bpf(cmd, KERNEL_BPFPTR(attr), attr_size); 4804 } 4805 EXPORT_SYMBOL(bpf_sys_bpf); 4806 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org