Re: [PATCHv5 bpf-next 9/9] bpf,x86: Use single ftrace_ops for direct calls

[kernel test robot <lkp@intel.com>]

Hi Jiri,

kernel test robot noticed the following build errors:

[auto build test ERROR on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Jiri-Olsa/ftrace-bpf-Remove-FTRACE_OPS_FL_JMP-ftrace_ops-flag/20251216-052916
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20251215211402.353056-10-jolsa%40kernel.org
patch subject: [PATCHv5 bpf-next 9/9] bpf,x86: Use single ftrace_ops for direct calls
config: riscv-allmodconfig (https://download.01.org/0day-ci/archive/20251221/202512210241.4wuAmCHu-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project b324c9f4fa112d61a553bf489b5f4f7ceea05ea8)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251221/202512210241.4wuAmCHu-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/202512210241.4wuAmCHu-lkp@intel.com/

All errors (new ones prefixed by >>):

>> kernel/bpf/trampoline.c:367:9: error: call to undeclared function 'direct_ops_del'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     367 |                 ret = direct_ops_del(tr, old_addr);
         |                       ^
   kernel/bpf/trampoline.c:367:9: note: did you mean 'direct_ops_free'?
   kernel/bpf/trampoline.c:298:13: note: 'direct_ops_free' declared here
     298 | static void direct_ops_free(struct bpf_trampoline *tr) { }
         |             ^
>> kernel/bpf/trampoline.c:381:9: error: call to undeclared function 'direct_ops_mod'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     381 |                 ret = direct_ops_mod(tr, new_addr, lock_direct_mutex);
         |                       ^
   kernel/bpf/trampoline.c:381:9: note: did you mean 'direct_ops_free'?
   kernel/bpf/trampoline.c:298:13: note: 'direct_ops_free' declared here
     298 | static void direct_ops_free(struct bpf_trampoline *tr) { }
         |             ^
>> kernel/bpf/trampoline.c:404:9: error: call to undeclared function 'direct_ops_add'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     404 |                 ret = direct_ops_add(tr, new_addr);
         |                       ^
   kernel/bpf/trampoline.c:404:9: note: did you mean 'direct_ops_free'?
   kernel/bpf/trampoline.c:298:13: note: 'direct_ops_free' declared here
     298 | static void direct_ops_free(struct bpf_trampoline *tr) { }
         |             ^
   3 errors generated.


vim +/direct_ops_del +367 kernel/bpf/trampoline.c

   360	
   361	static int unregister_fentry(struct bpf_trampoline *tr, u32 orig_flags,
   362				     void *old_addr)
   363	{
   364		int ret;
   365	
   366		if (tr->func.ftrace_managed)
 > 367			ret = direct_ops_del(tr, old_addr);
   368		else
   369			ret = bpf_trampoline_update_fentry(tr, orig_flags, old_addr, NULL);
   370	
   371		return ret;
   372	}
   373	
   374	static int modify_fentry(struct bpf_trampoline *tr, u32 orig_flags,
   375				 void *old_addr, void *new_addr,
   376				 bool lock_direct_mutex)
   377	{
   378		int ret;
   379	
   380		if (tr->func.ftrace_managed) {
 > 381			ret = direct_ops_mod(tr, new_addr, lock_direct_mutex);
   382		} else {
   383			ret = bpf_trampoline_update_fentry(tr, orig_flags, old_addr,
   384							   new_addr);
   385		}
   386		return ret;
   387	}
   388	
   389	/* first time registering */
   390	static int register_fentry(struct bpf_trampoline *tr, void *new_addr)
   391	{
   392		void *ip = tr->func.addr;
   393		unsigned long faddr;
   394		int ret;
   395	
   396		faddr = ftrace_location((unsigned long)ip);
   397		if (faddr) {
   398			if (!tr->fops)
   399				return -ENOTSUPP;
   400			tr->func.ftrace_managed = true;
   401		}
   402	
   403		if (tr->func.ftrace_managed) {
 > 404			ret = direct_ops_add(tr, new_addr);
   405		} else {
   406			ret = bpf_trampoline_update_fentry(tr, 0, NULL, new_addr);
   407		}
   408	
   409		return ret;
   410	}
   411	

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