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Date:   Fri, 3 Nov 2023 00:19:40 +0800
From:   Philip Li <philip.li@intel.com>
To:     Yonghong Song <yonghong.song@linux.dev>
CC:     kernel test robot <lkp@intel.com>, <oe-kbuild-all@lists.linux.dev>,
        <linux-kernel@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>
Subject: Re: kernel/bpf/helpers.c:1905:19: warning: no previous declaration
 for 'bpf_percpu_obj_new_impl'
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On Thu, Nov 02, 2023 at 08:36:16AM -0700, Yonghong Song wrote:
> 
> On 11/2/23 2:06 AM, Philip Li wrote:
> > On Thu, Nov 02, 2023 at 04:42:39PM +0800, kernel test robot wrote:
> > > Hi Yonghong,
> > Sorry, kindly ignore this report, it is similar one as https://lore.kernel.org/oe-kbuild-all/202309241550.JnHcYTZh-lkp@intel.com/,
> > and we haven't fixed the bot side yet.
> 
> The fix is just pushed to the bpf tree.
> 
> https://lore.kernel.org/all/20231031215625.2343848-1-davemarchevsky@fb.com/

Got it, thanks for the info.

BTW: I found a few places in kernel only handle -Wmissing-prototypes but not
-Wmissing-declarations when using __diag_ignore_all. Initially the bot only
run with -Wno-missing-prototypes for old compiler, which leads to -Wmissing-declarations
warnings still being reported.

What the bot does now is run with both -Wno-missing-prototypes and -Wno-missing-declarations
now for gcc older than gcc-8.

> 
> 
> > 
> > > FYI, the error/warning still remains.
> > > 
> > > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > > head:   21e80f3841c01aeaf32d7aee7bbc87b3db1aa0c6
> > > commit: 36d8bdf75a93190e5669b9d1d95994e13e15ba1d bpf: Add alloc/xchg/direct_access support for local percpu kptr
> > > date:   8 weeks ago
> > > config: x86_64-buildonly-randconfig-006-20231102 (https://download.01.org/0day-ci/archive/20231102/202311021613.I5dZri9c-lkp@intel.com/config)
> > > compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
> > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231102/202311021613.I5dZri9c-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/202311021613.I5dZri9c-lkp@intel.com/
> > > 
> > > All warnings (new ones prefixed by >>):
> > > 
> > >     kernel/bpf/helpers.c:1891:19: warning: no previous declaration for 'bpf_obj_new_impl' [-Wmissing-declarations]
> > >      __bpf_kfunc void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign)
> > >                        ^~~~~~~~~~~~~~~~
> > > > > kernel/bpf/helpers.c:1905:19: warning: no previous declaration for 'bpf_percpu_obj_new_impl' [-Wmissing-declarations]
> > >      __bpf_kfunc void *bpf_percpu_obj_new_impl(u64 local_type_id__k, void *meta__ign)
> > >                        ^~~~~~~~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:1933:18: warning: no previous declaration for 'bpf_obj_drop_impl' [-Wmissing-declarations]
> > >      __bpf_kfunc void bpf_obj_drop_impl(void *p__alloc, void *meta__ign)
> > >                       ^~~~~~~~~~~~~~~~~
> > > > > kernel/bpf/helpers.c:1941:18: warning: no previous declaration for 'bpf_percpu_obj_drop_impl' [-Wmissing-declarations]
> > >      __bpf_kfunc void bpf_percpu_obj_drop_impl(void *p__alloc, void *meta__ign)
> > >                       ^~~~~~~~~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:1947:19: warning: no previous declaration for 'bpf_refcount_acquire_impl' [-Wmissing-declarations]
> > >      __bpf_kfunc void *bpf_refcount_acquire_impl(void *p__refcounted_kptr, void *meta__ign)
> > >                        ^~~~~~~~~~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:1992:17: warning: no previous declaration for 'bpf_list_push_front_impl' [-Wmissing-declarations]
> > >      __bpf_kfunc int bpf_list_push_front_impl(struct bpf_list_head *head,
> > >                      ^~~~~~~~~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2002:17: warning: no previous declaration for 'bpf_list_push_back_impl' [-Wmissing-declarations]
> > >      __bpf_kfunc int bpf_list_push_back_impl(struct bpf_list_head *head,
> > >                      ^~~~~~~~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2035:35: warning: no previous declaration for 'bpf_list_pop_front' [-Wmissing-declarations]
> > >      __bpf_kfunc struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head)
> > >                                        ^~~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2040:35: warning: no previous declaration for 'bpf_list_pop_back' [-Wmissing-declarations]
> > >      __bpf_kfunc struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head)
> > >                                        ^~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2045:33: warning: no previous declaration for 'bpf_rbtree_remove' [-Wmissing-declarations]
> > >      __bpf_kfunc struct bpf_rb_node *bpf_rbtree_remove(struct bpf_rb_root *root,
> > >                                      ^~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2101:17: warning: no previous declaration for 'bpf_rbtree_add_impl' [-Wmissing-declarations]
> > >      __bpf_kfunc int bpf_rbtree_add_impl(struct bpf_rb_root *root, struct bpf_rb_node *node,
> > >                      ^~~~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2111:33: warning: no previous declaration for 'bpf_rbtree_first' [-Wmissing-declarations]
> > >      __bpf_kfunc struct bpf_rb_node *bpf_rbtree_first(struct bpf_rb_root *root)
> > >                                      ^~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2124:33: warning: no previous declaration for 'bpf_task_acquire' [-Wmissing-declarations]
> > >      __bpf_kfunc struct task_struct *bpf_task_acquire(struct task_struct *p)
> > >                                      ^~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2135:18: warning: no previous declaration for 'bpf_task_release' [-Wmissing-declarations]
> > >      __bpf_kfunc void bpf_task_release(struct task_struct *p)
> > >                       ^~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2224:33: warning: no previous declaration for 'bpf_task_from_pid' [-Wmissing-declarations]
> > >      __bpf_kfunc struct task_struct *bpf_task_from_pid(s32 pid)
> > >                                      ^~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2265:19: warning: no previous declaration for 'bpf_dynptr_slice' [-Wmissing-declarations]
> > >      __bpf_kfunc void *bpf_dynptr_slice(const struct bpf_dynptr_kern *ptr, u32 offset,
> > >                        ^~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2349:19: warning: no previous declaration for 'bpf_dynptr_slice_rdwr' [-Wmissing-declarations]
> > >      __bpf_kfunc void *bpf_dynptr_slice_rdwr(const struct bpf_dynptr_kern *ptr, u32 offset,
> > >                        ^~~~~~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2380:17: warning: no previous declaration for 'bpf_dynptr_adjust' [-Wmissing-declarations]
> > >      __bpf_kfunc int bpf_dynptr_adjust(struct bpf_dynptr_kern *ptr, u32 start, u32 end)
> > >                      ^~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2398:18: warning: no previous declaration for 'bpf_dynptr_is_null' [-Wmissing-declarations]
> > >      __bpf_kfunc bool bpf_dynptr_is_null(struct bpf_dynptr_kern *ptr)
> > >                       ^~~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2403:18: warning: no previous declaration for 'bpf_dynptr_is_rdonly' [-Wmissing-declarations]
> > >      __bpf_kfunc bool bpf_dynptr_is_rdonly(struct bpf_dynptr_kern *ptr)
> > >                       ^~~~~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2411:19: warning: no previous declaration for 'bpf_dynptr_size' [-Wmissing-declarations]
> > >      __bpf_kfunc __u32 bpf_dynptr_size(const struct bpf_dynptr_kern *ptr)
> > >                        ^~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2419:17: warning: no previous declaration for 'bpf_dynptr_clone' [-Wmissing-declarations]
> > >      __bpf_kfunc int bpf_dynptr_clone(struct bpf_dynptr_kern *ptr,
> > >                      ^~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2432:19: warning: no previous declaration for 'bpf_cast_to_kern_ctx' [-Wmissing-declarations]
> > >      __bpf_kfunc void *bpf_cast_to_kern_ctx(void *obj)
> > >                        ^~~~~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2437:19: warning: no previous declaration for 'bpf_rdonly_cast' [-Wmissing-declarations]
> > >      __bpf_kfunc void *bpf_rdonly_cast(void *obj__ign, u32 btf_id__k)
> > >                        ^~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2442:18: warning: no previous declaration for 'bpf_rcu_read_lock' [-Wmissing-declarations]
> > >      __bpf_kfunc void bpf_rcu_read_lock(void)
> > >                       ^~~~~~~~~~~~~~~~~
> > >     kernel/bpf/helpers.c:2447:18: warning: no previous declaration for 'bpf_rcu_read_unlock' [-Wmissing-declarations]
> > >      __bpf_kfunc void bpf_rcu_read_unlock(void)
> > >                       ^~~~~~~~~~~~~~~~~~~
> > > 
> > > 
> > > vim +/bpf_percpu_obj_new_impl +1905 kernel/bpf/helpers.c
> > > 
> > >    1904	
> > > > 1905	__bpf_kfunc void *bpf_percpu_obj_new_impl(u64 local_type_id__k, void *meta__ign)
> > >    1906	{
> > >    1907		u64 size = local_type_id__k;
> > >    1908	
> > >    1909		/* The verifier has ensured that meta__ign must be NULL */
> > >    1910		return bpf_mem_alloc(&bpf_global_percpu_ma, size);
> > >    1911	}
> > >    1912	
> > >    1913	/* Must be called under migrate_disable(), as required by bpf_mem_free */
> > >    1914	void __bpf_obj_drop_impl(void *p, const struct btf_record *rec)
> > >    1915	{
> > >    1916		if (rec && rec->refcount_off >= 0 &&
> > >    1917		    !refcount_dec_and_test((refcount_t *)(p + rec->refcount_off))) {
> > >    1918			/* Object is refcounted and refcount_dec didn't result in 0
> > >    1919			 * refcount. Return without freeing the object
> > >    1920			 */
> > >    1921			return;
> > >    1922		}
> > >    1923	
> > >    1924		if (rec)
> > >    1925			bpf_obj_free_fields(rec, p);
> > >    1926	
> > >    1927		if (rec && rec->refcount_off >= 0)
> > >    1928			bpf_mem_free_rcu(&bpf_global_ma, p);
> > >    1929		else
> > >    1930			bpf_mem_free(&bpf_global_ma, p);
> > >    1931	}
> > >    1932	
> > >    1933	__bpf_kfunc void bpf_obj_drop_impl(void *p__alloc, void *meta__ign)
> > >    1934	{
> > >    1935		struct btf_struct_meta *meta = meta__ign;
> > >    1936		void *p = p__alloc;
> > >    1937	
> > >    1938		__bpf_obj_drop_impl(p, meta ? meta->record : NULL);
> > >    1939	}
> > >    1940	
> > > > 1941	__bpf_kfunc void bpf_percpu_obj_drop_impl(void *p__alloc, void *meta__ign)
> > >    1942	{
> > >    1943		/* The verifier has ensured that meta__ign must be NULL */
> > >    1944		bpf_mem_free_rcu(&bpf_global_percpu_ma, p__alloc);
> > >    1945	}
> > >    1946	
> > > 
> > > -- 
> > > 0-DAY CI Kernel Test Service
> > > https://github.com/intel/lkp-tests/wiki
> > > 
>