On Thu, Jul 04, 2024 at 11:38:46AM +0800, kernel test robot wrote: > Hi Alexandre, > > kernel test robot noticed the following build errors: > > [auto build test ERROR on soc/for-next] > [also build test ERROR on linus/master v6.10-rc6 next-20240703] > [cannot apply to arnd-asm-generic/master robh/for-next tip/locking/core] > [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/Alexandre-Ghiti/riscv-Implement-cmpxchg32-64-using-Zacas/20240627-034946 > base: https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next > patch link: https://lore.kernel.org/r/20240626130347.520750-2-alexghiti%40rivosinc.com > patch subject: [PATCH v2 01/10] riscv: Implement cmpxchg32/64() using Zacas > config: riscv-randconfig-002-20240704 (https://download.01.org/0day-ci/archive/20240704/202407041157.odTZAYZ6-lkp@xxxxxxxxx/config) > compiler: clang version 16.0.6 (https://github.com/llvm/llvm-project 7cbf1a2591520c2491aa35339f227775f4d3adf6) > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240704/202407041157.odTZAYZ6-lkp@xxxxxxxxx/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@xxxxxxxxx> > | Closes: https://lore.kernel.org/oe-kbuild-all/202407041157.odTZAYZ6-lkp@xxxxxxxxx/ > > All errors (new ones prefixed by >>): > > >> kernel/sched/core.c:11873:7: error: cannot jump from this asm goto statement to one of its possible targets > if (try_cmpxchg(&pcpu_cid->cid, &lazy_cid, MM_CID_UNSET)) > ^ > include/linux/atomic/atomic-instrumented.h:4880:2: note: expanded from macro 'try_cmpxchg' > raw_try_cmpxchg(__ai_ptr, __ai_oldp, __VA_ARGS__); \ > ^ > include/linux/atomic/atomic-arch-fallback.h:192:9: note: expanded from macro 'raw_try_cmpxchg' > ___r = raw_cmpxchg((_ptr), ___o, (_new)); \ > ^ > include/linux/atomic/atomic-arch-fallback.h:55:21: note: expanded from macro 'raw_cmpxchg' > #define raw_cmpxchg arch_cmpxchg > ^ > arch/riscv/include/asm/cmpxchg.h:212:2: note: expanded from macro 'arch_cmpxchg' > _arch_cmpxchg((ptr), (o), (n), ".rl", "", " fence rw, rw\n") > ^ > arch/riscv/include/asm/cmpxchg.h:189:3: note: expanded from macro '_arch_cmpxchg' > __arch_cmpxchg(".w", ".w" sc_sfx, prepend, append, \ > ^ > arch/riscv/include/asm/cmpxchg.h:144:3: note: expanded from macro '__arch_cmpxchg' > asm goto(ALTERNATIVE("nop", "j %[zacas]", 0, \ > ^ > kernel/sched/core.c:11840:7: note: possible target of asm goto statement > if (!try_cmpxchg(&pcpu_cid->cid, &cid, lazy_cid)) > ^ > include/linux/atomic/atomic-instrumented.h:4880:2: note: expanded from macro 'try_cmpxchg' > raw_try_cmpxchg(__ai_ptr, __ai_oldp, __VA_ARGS__); \ > ^ > include/linux/atomic/atomic-arch-fallback.h:192:9: note: expanded from macro 'raw_try_cmpxchg' > ___r = raw_cmpxchg((_ptr), ___o, (_new)); \ > ^ > include/linux/atomic/atomic-arch-fallback.h:55:21: note: expanded from macro 'raw_cmpxchg' > #define raw_cmpxchg arch_cmpxchg > ^ > arch/riscv/include/asm/cmpxchg.h:212:2: note: expanded from macro 'arch_cmpxchg' > _arch_cmpxchg((ptr), (o), (n), ".rl", "", " fence rw, rw\n") > ^ > arch/riscv/include/asm/cmpxchg.h:189:3: note: expanded from macro '_arch_cmpxchg' > __arch_cmpxchg(".w", ".w" sc_sfx, prepend, append, \ > ^ > arch/riscv/include/asm/cmpxchg.h:161:10: note: expanded from macro '__arch_cmpxchg' > \ > ^ > kernel/sched/core.c:11872:2: note: jump exits scope of variable with __attribute__((cleanup)) > scoped_guard (irqsave) { > ^ > include/linux/cleanup.h:169:20: note: expanded from macro 'scoped_guard' > for (CLASS(_name, scope)(args), \ > ^ > kernel/sched/core.c:11840:7: error: cannot jump from this asm goto statement to one of its possible targets > if (!try_cmpxchg(&pcpu_cid->cid, &cid, lazy_cid)) > ^ > include/linux/atomic/atomic-instrumented.h:4880:2: note: expanded from macro 'try_cmpxchg' > raw_try_cmpxchg(__ai_ptr, __ai_oldp, __VA_ARGS__); \ > ^ > include/linux/atomic/atomic-arch-fallback.h:192:9: note: expanded from macro 'raw_try_cmpxchg' > ___r = raw_cmpxchg((_ptr), ___o, (_new)); \ > ^ > include/linux/atomic/atomic-arch-fallback.h:55:21: note: expanded from macro 'raw_cmpxchg' > #define raw_cmpxchg arch_cmpxchg > ^ > arch/riscv/include/asm/cmpxchg.h:212:2: note: expanded from macro 'arch_cmpxchg' > _arch_cmpxchg((ptr), (o), (n), ".rl", "", " fence rw, rw\n") > ^ > arch/riscv/include/asm/cmpxchg.h:189:3: note: expanded from macro '_arch_cmpxchg' > __arch_cmpxchg(".w", ".w" sc_sfx, prepend, append, \ > ^ > arch/riscv/include/asm/cmpxchg.h:144:3: note: expanded from macro '__arch_cmpxchg' > asm goto(ALTERNATIVE("nop", "j %[zacas]", 0, \ > ^ > kernel/sched/core.c:11873:7: note: possible target of asm goto statement > if (try_cmpxchg(&pcpu_cid->cid, &lazy_cid, MM_CID_UNSET)) > ^ > include/linux/atomic/atomic-instrumented.h:4880:2: note: expanded from macro 'try_cmpxchg' > raw_try_cmpxchg(__ai_ptr, __ai_oldp, __VA_ARGS__); \ > ^ > include/linux/atomic/atomic-arch-fallback.h:192:9: note: expanded from macro 'raw_try_cmpxchg' > ___r = raw_cmpxchg((_ptr), ___o, (_new)); \ > ^ > include/linux/atomic/atomic-arch-fallback.h:55:21: note: expanded from macro 'raw_cmpxchg' > #define raw_cmpxchg arch_cmpxchg > ^ > arch/riscv/include/asm/cmpxchg.h:212:2: note: expanded from macro 'arch_cmpxchg' > _arch_cmpxchg((ptr), (o), (n), ".rl", "", " fence rw, rw\n") > ^ > arch/riscv/include/asm/cmpxchg.h:189:3: note: expanded from macro '_arch_cmpxchg' > __arch_cmpxchg(".w", ".w" sc_sfx, prepend, append, \ > ^ > arch/riscv/include/asm/cmpxchg.h:161:10: note: expanded from macro '__arch_cmpxchg' > \ > ^ > kernel/sched/core.c:11872:2: note: jump bypasses initialization of variable with __attribute__((cleanup)) > scoped_guard (irqsave) { > ^ > include/linux/cleanup.h:169:20: note: expanded from macro 'scoped_guard' > for (CLASS(_name, scope)(args), \ > ^ > 2 errors generated. Ugh, this is an unfortunate interaction with clang's jump scope analysis and asm goto in LLVM releases prior to 17 :/ https://github.com/ClangBuiltLinux/linux/issues/1886#issuecomment-1645979992 Unfortunately, 'if (0)' does not prevent this (the analysis runs early in the front end as far as I understand it), we would need to workaround this with full preprocessor guards... Another alternative would be to require LLVM 17+ for RISC-V, which may not be the worst alternative, since I think most people doing serious work with clang will probably be living close to tip of tree anyways because of all the extension work that goes on upstream. I am open to other thoughts though. Cheers, Nathan
