Re: [ammarfaizi2-block:paulmck/linux-rcu/dave.2022.06.02a 56/78] kernel/rcu/tasks.h:1239:8: error: variable has incomplete type 'typeof (({
From: Paul E. McKenney
Date: Thu Jun 02 2022 - 19:52:10 EST
On Fri, Jun 03, 2022 at 06:15:47AM +0800, kernel test robot wrote:
> tree: https://github.com/ammarfaizi2/linux-block paulmck/linux-rcu/dave.2022.06.02a
> head: 2efc5c4abe4cc1259378f7c1678a93540559673c
> commit: cda3200416cdef7f25546cd6249fb411c8c32079 [56/78] rcu-tasks: Merge state into .b.need_qs and atomically update
> config: arm-buildonly-randconfig-r004-20220531 (https://download.01.org/0day-ci/archive/20220603/202206030613.IxQYmIW8-lkp@xxxxxxxxx/config)
> compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project b364c76683f8ef241025a9556300778c07b590c2)
> 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 arm cross compiling tool for clang build
> # apt-get install binutils-arm-linux-gnueabi
> # https://github.com/ammarfaizi2/linux-block/commit/cda3200416cdef7f25546cd6249fb411c8c32079
> git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
> git fetch --no-tags ammarfaizi2-block paulmck/linux-rcu/dave.2022.06.02a
> git checkout cda3200416cdef7f25546cd6249fb411c8c32079
> # save the config file
> mkdir build_dir && cp config build_dir/.config
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
OK, I finally get it. The NIOS2 and ARM CPUs' implementations of
cmpxchg are not type-generic, are they?
OK, I will fix this, though the type-checking is rather nice.
Adding some NIOS2 and ARM people/lists on CC for their thoughts.
Thanx, Paul
> All errors (new ones prefixed by >>):
>
> In file included from kernel/rcu/update.c:606:
> kernel/rcu/tasks.h:1239:8: error: operand of type 'union rcu_special' where arithmetic or pointer type is required
> ret = cmpxchg(&t->trc_reader_special, trs_old, trs_new);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic/atomic-instrumented.h:1916:2: note: expanded from macro 'cmpxchg'
> arch_cmpxchg(__ai_ptr, __VA_ARGS__); \
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic/atomic-arch-fallback.h:52:2: note: expanded from macro 'arch_cmpxchg'
> __atomic_op_fence(arch_cmpxchg, __VA_ARGS__)
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic.h:73:9: note: expanded from macro '__atomic_op_fence'
> typeof(op##_relaxed(args)) __ret; \
> ^~~~~~~~~~~~~~~~~~
> <scratch space>:39:1: note: expanded from here
> arch_cmpxchg_relaxed
> ^
> arch/arm/include/asm/cmpxchg.h:212:26: note: expanded from macro 'arch_cmpxchg_relaxed'
> (unsigned long)(o), \
> ^~~
> In file included from kernel/rcu/update.c:606:
> kernel/rcu/tasks.h:1239:8: error: operand of type 'union rcu_special' where arithmetic or pointer type is required
> ret = cmpxchg(&t->trc_reader_special, trs_old, trs_new);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic/atomic-instrumented.h:1916:2: note: expanded from macro 'cmpxchg'
> arch_cmpxchg(__ai_ptr, __VA_ARGS__); \
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic/atomic-arch-fallback.h:52:2: note: expanded from macro 'arch_cmpxchg'
> __atomic_op_fence(arch_cmpxchg, __VA_ARGS__)
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic.h:73:9: note: expanded from macro '__atomic_op_fence'
> typeof(op##_relaxed(args)) __ret; \
> ^~~~~~~~~~~~~~~~~~
> <scratch space>:39:1: note: expanded from here
> arch_cmpxchg_relaxed
> ^
> arch/arm/include/asm/cmpxchg.h:213:26: note: expanded from macro 'arch_cmpxchg_relaxed'
> (unsigned long)(n), \
> ^~~
> In file included from kernel/rcu/update.c:606:
> >> kernel/rcu/tasks.h:1239:8: error: variable has incomplete type 'typeof (({
> }))' (aka 'void')
> include/linux/atomic/atomic-instrumented.h:1916:2: note: expanded from macro 'cmpxchg'
> arch_cmpxchg(__ai_ptr, __VA_ARGS__); \
> ^
> include/linux/atomic/atomic-arch-fallback.h:52:2: note: expanded from macro 'arch_cmpxchg'
> __atomic_op_fence(arch_cmpxchg, __VA_ARGS__)
> ^
> include/linux/atomic.h:73:29: note: expanded from macro '__atomic_op_fence'
> typeof(op##_relaxed(args)) __ret; \
> ^
> In file included from kernel/rcu/update.c:606:
> kernel/rcu/tasks.h:1239:8: error: operand of type 'union rcu_special' where arithmetic or pointer type is required
> ret = cmpxchg(&t->trc_reader_special, trs_old, trs_new);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic/atomic-instrumented.h:1916:2: note: expanded from macro 'cmpxchg'
> arch_cmpxchg(__ai_ptr, __VA_ARGS__); \
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic/atomic-arch-fallback.h:52:2: note: expanded from macro 'arch_cmpxchg'
> __atomic_op_fence(arch_cmpxchg, __VA_ARGS__)
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic.h:75:10: note: expanded from macro '__atomic_op_fence'
> __ret = op##_relaxed(args); \
> ^~~~~~~~~~~~~~~~~~
> <scratch space>:40:1: note: expanded from here
> arch_cmpxchg_relaxed
> ^
> arch/arm/include/asm/cmpxchg.h:212:26: note: expanded from macro 'arch_cmpxchg_relaxed'
> (unsigned long)(o), \
> ^~~
> In file included from kernel/rcu/update.c:606:
> kernel/rcu/tasks.h:1239:8: error: operand of type 'union rcu_special' where arithmetic or pointer type is required
> ret = cmpxchg(&t->trc_reader_special, trs_old, trs_new);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic/atomic-instrumented.h:1916:2: note: expanded from macro 'cmpxchg'
> arch_cmpxchg(__ai_ptr, __VA_ARGS__); \
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic/atomic-arch-fallback.h:52:2: note: expanded from macro 'arch_cmpxchg'
> __atomic_op_fence(arch_cmpxchg, __VA_ARGS__)
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/atomic.h:75:10: note: expanded from macro '__atomic_op_fence'
> __ret = op##_relaxed(args); \
> ^~~~~~~~~~~~~~~~~~
> <scratch space>:40:1: note: expanded from here
> arch_cmpxchg_relaxed
> ^
> arch/arm/include/asm/cmpxchg.h:213:26: note: expanded from macro 'arch_cmpxchg_relaxed'
> (unsigned long)(n), \
> ^~~
> 5 errors generated.
>
>
> vim +1239 kernel/rcu/tasks.h
>
> 1224
> 1225 /*
> 1226 * Do a cmpxchg() on ->trc_reader_special.b.need_qs, allowing for
> 1227 * the four-byte operand-size restriction of some platforms.
> 1228 * Returns the old value, which is often ignored.
> 1229 */
> 1230 u8 rcu_trc_cmpxchg_need_qs(struct task_struct *t, u8 old, u8 new)
> 1231 {
> 1232 union rcu_special ret;
> 1233 union rcu_special trs_old = READ_ONCE(t->trc_reader_special);
> 1234 union rcu_special trs_new = trs_old;
> 1235
> 1236 if (trs_old.b.need_qs != old)
> 1237 return trs_old.b.need_qs;
> 1238 trs_new.b.need_qs = new;
> > 1239 ret = cmpxchg(&t->trc_reader_special, trs_old, trs_new);
> 1240 return ret.b.need_qs;
> 1241 }
> 1242 EXPORT_SYMBOL_GPL(rcu_trc_cmpxchg_need_qs);
> 1243
>
> --
> 0-DAY CI Kernel Test Service
> https://01.org/lkp