Subject: linux-next: build warning after merge of the kspp-gustavo tree

From: Stephen Rothwell <[email-masked]>
Date: Thu, 30 Sep 2021 09:53:00 +1000

Hi all,

After merging the kspp-gustavo tree, today's linux-next build (powerpc
ppc64_defconfig) produced this warning:

kernel/trace/ftrace.c: In function 'ftrace_ops_get_list_func':
kernel/trace/ftrace.c:128:31: warning: cast between incompatible function types from 'void (*)(long unsigned int,  long unsigned int)' to 'void (*)(long unsigned int,  long unsigned int,  struct ftrace_ops *, struct ftrace_regs *)' [-Wcast-function-type]
  128 | #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
      |                               ^
kernel/trace/ftrace.c:174:10: note: in expansion of macro 'ftrace_ops_list_func'
  174 |   return ftrace_ops_list_func;
      |          ^~~~~~~~~~~~~~~~~~~~
kernel/trace/ftrace.c: In function 'update_ftrace_function':
kernel/trace/ftrace.c:128:31: warning: cast between incompatible function types from 'void (*)(long unsigned int,  long unsigned int)' to 'void (*)(long unsigned int,  long unsigned int,  struct ftrace_ops *, struct ftrace_regs *)' [-Wcast-function-type]
  128 | #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
      |                               ^
kernel/trace/ftrace.c:207:10: note: in expansion of macro 'ftrace_ops_list_func'
  207 |   func = ftrace_ops_list_func;
      |          ^~~~~~~~~~~~~~~~~~~~
kernel/trace/ftrace.c:128:31: warning: cast between incompatible function types from 'void (*)(long unsigned int,  long unsigned int)' to 'void (*)(long unsigned int,  long unsigned int,  struct ftrace_ops *, struct ftrace_regs *)' [-Wcast-function-type]
  128 | #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
      |                               ^
kernel/trace/ftrace.c:220:14: note: in expansion of macro 'ftrace_ops_list_func'
  220 |  if (func == ftrace_ops_list_func) {
      |              ^~~~~~~~~~~~~~~~~~~~
kernel/trace/ftrace.c: In function 'ftrace_modify_all_code':
kernel/trace/ftrace.c:128:31: warning: cast between incompatible function types from 'void (*)(long unsigned int,  long unsigned int)' to 'void (*)(long unsigned int,  long unsigned int,  struct ftrace_ops *, struct ftrace_regs *)' [-Wcast-function-type]
  128 | #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
      |                               ^
kernel/trace/ftrace.c:2698:35: note: in expansion of macro 'ftrace_ops_list_func'
 2698 |   err = ftrace_update_ftrace_func(ftrace_ops_list_func);
      |                                   ^~~~~~~~~~~~~~~~~~~~
kernel/trace/ftrace.c:128:31: warning: cast between incompatible function types from 'void (*)(long unsigned int,  long unsigned int)' to 'void (*)(long unsigned int,  long unsigned int,  struct ftrace_ops *, struct ftrace_regs *)' [-Wcast-function-type]
  128 | #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
      |                               ^
kernel/trace/ftrace.c:2708:41: note: in expansion of macro 'ftrace_ops_list_func'
 2708 |  if (update && ftrace_trace_function != ftrace_ops_list_func) {
      |                                         ^~~~~~~~~~~~~~~~~~~~
In file included from kernel/bpf/hashtab.c:8:
kernel/bpf/hashtab.c: In function 'htab_map_gen_lookup':
include/linux/filter.h:366:4: warning: cast between incompatible function types from 'void * (*)(struct bpf_map *, void *)' to 'u64 (*)(u64,  u64,  u64,  u64,  u64)' {aka 'long long unsigned int (*)(long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int)'} [-Wcast-function-type]
  366 |   ((u64 (*)(u64, u64, u64, u64, u64))(x))
      |    ^
include/linux/filter.h:374:14: note: in definition of macro 'BPF_EMIT_CALL'
  374 |   .imm   = ((FUNC) - __bpf_call_base) })
      |              ^~~~
kernel/bpf/hashtab.c:671:26: note: in expansion of macro 'BPF_CAST_CALL'
  671 |  *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
      |                          ^~~~~~~~~~~~~
kernel/bpf/hashtab.c: In function 'htab_lru_map_gen_lookup':
include/linux/filter.h:366:4: warning: cast between incompatible function types from 'void * (*)(struct bpf_map *, void *)' to 'u64 (*)(u64,  u64,  u64,  u64,  u64)' {aka 'long long unsigned int (*)(long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int)'} [-Wcast-function-type]
  366 |   ((u64 (*)(u64, u64, u64, u64, u64))(x))
      |    ^
include/linux/filter.h:374:14: note: in definition of macro 'BPF_EMIT_CALL'
  374 |   .imm   = ((FUNC) - __bpf_call_base) })
      |              ^~~~
kernel/bpf/hashtab.c:712:26: note: in expansion of macro 'BPF_CAST_CALL'
  712 |  *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
      |                          ^~~~~~~~~~~~~
kernel/bpf/hashtab.c: In function 'htab_of_map_gen_lookup':
include/linux/filter.h:366:4: warning: cast between incompatible function types from 'void * (*)(struct bpf_map *, void *)' to 'u64 (*)(u64,  u64,  u64,  u64,  u64)' {aka 'long long unsigned int (*)(long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int)'} [-Wcast-function-type]
  366 |   ((u64 (*)(u64, u64, u64, u64, u64))(x))
      |    ^
include/linux/filter.h:374:14: note: in definition of macro 'BPF_EMIT_CALL'
  374 |   .imm   = ((FUNC) - __bpf_call_base) })
      |              ^~~~
kernel/bpf/hashtab.c:2400:26: note: in expansion of macro 'BPF_CAST_CALL'
 2400 |  *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem));
      |                          ^~~~~~~~~~~~~
In file included from include/linux/bpf_verifier.h:9,
                 from kernel/bpf/verifier.c:12:
kernel/bpf/verifier.c: In function 'jit_subprogs':
include/linux/filter.h:366:4: warning: cast between incompatible function types from 'unsigned int (*)(const void *, const struct bpf_insn *)' to 'u64 (*)(u64,  u64,  u64,  u64,  u64)' {aka 'long long unsigned int (*)(long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int)'} [-Wcast-function-type]
  366 |   ((u64 (*)(u64, u64, u64, u64, u64))(x))
      |    ^
kernel/bpf/verifier.c:12472:16: note: in expansion of macro 'BPF_CAST_CALL'
12472 |    insn->imm = BPF_CAST_CALL(func[subprog]->bpf_func) -
      |                ^~~~~~~~~~~~~
kernel/bpf/verifier.c: In function 'do_misc_fixups':
include/linux/filter.h:366:4: warning: cast between incompatible function types from 'void * (* const)(struct bpf_map *, void *)' to 'u64 (*)(u64,  u64,  u64,  u64,  u64)' {aka 'long long unsigned int (*)(long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int)'} [-Wcast-function-type]
  366 |   ((u64 (*)(u64, u64, u64, u64, u64))(x))
      |    ^
kernel/bpf/verifier.c:12953:17: note: in expansion of macro 'BPF_CAST_CALL'
12953 |     insn->imm = BPF_CAST_CALL(ops->map_lookup_elem) -
      |                 ^~~~~~~~~~~~~
include/linux/filter.h:366:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, void *, void *, u64)' {aka 'int (* const)(struct bpf_map *, void *, void *, long long unsigned int)'} to 'u64 (*)(u64,  u64,  u64,  u64,  u64)' {aka 'long long unsigned int (*)(long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int)'} [-Wcast-function-type]
  366 |   ((u64 (*)(u64, u64, u64, u64, u64))(x))
      |    ^
kernel/bpf/verifier.c:12957:17: note: in expansion of macro 'BPF_CAST_CALL'
12957 |     insn->imm = BPF_CAST_CALL(ops->map_update_elem) -
      |                 ^~~~~~~~~~~~~
include/linux/filter.h:366:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, void *)' to 'u64 (*)(u64,  u64,  u64,  u64,  u64)' {aka 'long long unsigned int (*)(long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int)'} [-Wcast-function-type]
  366 |   ((u64 (*)(u64, u64, u64, u64, u64))(x))
      |    ^
kernel/bpf/verifier.c:12961:17: note: in expansion of macro 'BPF_CAST_CALL'
12961 |     insn->imm = BPF_CAST_CALL(ops->map_delete_elem) -
      |                 ^~~~~~~~~~~~~
include/linux/filter.h:366:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, void *, u64)' {aka 'int (* const)(struct bpf_map *, void *, long long unsigned int)'} to 'u64 (*)(u64,  u64,  u64,  u64,  u64)' {aka 'long long unsigned int (*)(long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int)'} [-Wcast-function-type]
  366 |   ((u64 (*)(u64, u64, u64, u64, u64))(x))
      |    ^
kernel/bpf/verifier.c:12965:17: note: in expansion of macro 'BPF_CAST_CALL'
12965 |     insn->imm = BPF_CAST_CALL(ops->map_push_elem) -
      |                 ^~~~~~~~~~~~~
include/linux/filter.h:366:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, void *)' to 'u64 (*)(u64,  u64,  u64,  u64,  u64)' {aka 'long long unsigned int (*)(long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int)'} [-Wcast-function-type]
  366 |   ((u64 (*)(u64, u64, u64, u64, u64))(x))
      |    ^
kernel/bpf/verifier.c:12969:17: note: in expansion of macro 'BPF_CAST_CALL'
12969 |     insn->imm = BPF_CAST_CALL(ops->map_pop_elem) -
      |                 ^~~~~~~~~~~~~
include/linux/filter.h:366:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, void *)' to 'u64 (*)(u64,  u64,  u64,  u64,  u64)' {aka 'long long unsigned int (*)(long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int)'} [-Wcast-function-type]
  366 |   ((u64 (*)(u64, u64, u64, u64, u64))(x))
      |    ^
kernel/bpf/verifier.c:12973:17: note: in expansion of macro 'BPF_CAST_CALL'
12973 |     insn->imm = BPF_CAST_CALL(ops->map_peek_elem) -
      |                 ^~~~~~~~~~~~~
include/linux/filter.h:366:4: warning: cast between incompatible function types from 'int (* const)(struct bpf_map *, u32,  u64)' {aka 'int (* const)(struct bpf_map *, unsigned int,  long long unsigned int)'} to 'u64 (*)(u64,  u64,  u64,  u64,  u64)' {aka 'long long unsigned int (*)(long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int,  long long unsigned int)'} [-Wcast-function-type]
  366 |   ((u64 (*)(u64, u64, u64, u64, u64))(x))
      |    ^
kernel/bpf/verifier.c:12977:17: note: in expansion of macro 'BPF_CAST_CALL'
12977 |     insn->imm = BPF_CAST_CALL(ops->map_redirect) -
      |                 ^~~~~~~~~~~~~

Introduced by commit

  ffea83dd8823 ("Makefile: Enable -Wcast-function-type")

Please either fix all these or revert that commit for now.

-- 
Cheers,
Stephen Rothwell