[axboe:rw_iter 322/525] arch/powerpc/kvm/timing.c:172:6: error: cannot take the address of an rvalue of type 'char *'

[axboe:rw_iter 322/525] arch/powerpc/kvm/timing.c:172:6: error: cannot take the address of an rvalue of type 'char *'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git rw_iter
head:   520344cda122ca1903fafb19768f56509e3db8b1
commit: 347664d07e7cc165e1dae2f95b2f6f1053a62844 [322/525] powerpc/kvm: convert to read/write iterators
config: powerpc64-randconfig-002-20260327 (https://download.01.org/0day-ci/archive/20260327/202603271712.kT4rdiHD-lkp@intel.com/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 054e11d1a17e5ba88bb1a8ef32fad3346e80b186)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260327/202603271712.kT4rdiHD-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603271712.kT4rdiHD-lkp@intel.com/

All errors (new ones prefixed by >>):

>> arch/powerpc/kvm/timing.c:172:6: error: cannot take the address of an rvalue of type 'char *'
     172 |         if (get_iter(&c, from)) {
         |             ^        ~~
   include/linux/uio.h:243:50: note: expanded from macro 'get_iter'
     243 | #define get_iter(val, from)     !copy_from_iter_full(&(val), sizeof((val)), from)
         |                                                      ^ ~~~
   include/linux/compiler.h:55:47: note: expanded from macro 'if'
      55 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
         |                                               ^~~~
   include/linux/compiler.h:57:52: note: expanded from macro '__trace_if_var'
      57 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
         |                                                    ^~~~
>> arch/powerpc/kvm/timing.c:172:6: error: cannot take the address of an rvalue of type 'char *'
     172 |         if (get_iter(&c, from)) {
         |             ^        ~~
   include/linux/uio.h:243:50: note: expanded from macro 'get_iter'
     243 | #define get_iter(val, from)     !copy_from_iter_full(&(val), sizeof((val)), from)
         |                                                      ^ ~~~
   include/linux/compiler.h:55:47: note: expanded from macro 'if'
      55 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
         |                                               ^~~~
   include/linux/compiler.h:57:61: note: expanded from macro '__trace_if_var'
      57 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
         |                                                             ^~~~
>> arch/powerpc/kvm/timing.c:172:6: error: cannot take the address of an rvalue of type 'char *'
     172 |         if (get_iter(&c, from)) {
         |             ^        ~~
   include/linux/uio.h:243:50: note: expanded from macro 'get_iter'
     243 | #define get_iter(val, from)     !copy_from_iter_full(&(val), sizeof((val)), from)
         |                                                      ^ ~~~
   include/linux/compiler.h:55:47: note: expanded from macro 'if'
      55 | #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
         |                                               ^~~~
   include/linux/compiler.h:57:86: note: expanded from macro '__trace_if_var'
      57 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
         |                                                                                      ^~~~
   include/linux/compiler.h:68:3: note: expanded from macro '__trace_if_value'
      68 |         (cond) ?                                        \
         |          ^~~~
   3 errors generated.


vim +172 arch/powerpc/kvm/timing.c

   159	
   160	/* Write 'c' to clear the timing statistics. */
   161	static ssize_t kvmppc_exit_timing_write(struct kiocb *iocb,
   162						struct iov_iter *from)
   163	{
   164		size_t count = iov_iter_count(from);
   165		int err = -EINVAL;
   166		char c;
   167	
   168		if (count > 1) {
   169			goto done;
   170		}
   171	
 > 172		if (get_iter(&c, from)) {
   173			err = -EFAULT;
   174			goto done;
   175		}
   176	
   177		if (c == 'c') {
   178			struct seq_file *seqf = iocb->ki_filp->private_data;
   179			struct kvm_vcpu *vcpu = seqf->private;
   180			/* Write does not affect our buffers previously generated with
   181			 * show. seq_file is locked here to prevent races of init with
   182			 * a show call */
   183			mutex_lock(&seqf->lock);
   184			kvmppc_init_timing_stats(vcpu);
   185			mutex_unlock(&seqf->lock);
   186			err = count;
   187		}
   188	
   189	done:
   190		return err;
   191	}
   192	

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