| Message ID | 20230816150634.1162838-1-void@manifault.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next] bpf: Disable -Wmissing-declarations for globally-linked kfuncs | expand |
On 8/16/23 8:06 AM, David Vernet wrote: > We recently got an lkp warning about missing declarations, as in e.g. > [0]. This warning is largely redundant with -Wmissing-prototypes, which > we already disable for kfuncs that have global linkage and are meant to > be exported in BTF, and called from BPF programs. Let's also disable > -Wmissing-declarations for kfuncs. For what it's worth, I wasn't able to > reproduce the warning even on W <= 3, so I can't actually be 100% sure > this fixes the issue. > > [0]: https://lore.kernel.org/all/202308162115.Hn23vv3n-lkp@intel.com/ Okay, I just got a similar email to [0] which complains bpf_obj_new_impl, ..., bpf_cast_to_kern_ctx missing declarations. In the email, the used compiler is compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 Unfortunately, I did not have gcc-7 to verify this. Also, what is the minimum gcc version kernel supports? 5.1? > > Reported-by: kernel test robot <lkp@intel.com> > Closes: https://lore.kernel.org/oe-kbuild-all/202308162115.Hn23vv3n-lkp@intel.com/ > Signed-off-by: David Vernet <void@manifault.com> > --- > Documentation/bpf/kfuncs.rst | 4 +++- > kernel/bpf/bpf_iter.c | 2 ++ > kernel/bpf/cpumask.c | 2 ++ > kernel/bpf/helpers.c | 2 ++ > kernel/bpf/map_iter.c | 2 ++ > kernel/cgroup/rstat.c | 2 ++ > kernel/trace/bpf_trace.c | 2 ++ > net/bpf/test_run.c | 2 ++ > net/core/filter.c | 4 ++++ > net/core/xdp.c | 2 ++ > net/ipv4/fou_bpf.c | 2 ++ > net/netfilter/nf_conntrack_bpf.c | 2 ++ > net/netfilter/nf_nat_bpf.c | 2 ++ > net/xfrm/xfrm_interface_bpf.c | 2 ++ > tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c | 2 ++ > 15 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst > index 0d2647fb358d..62ce5a7b92b4 100644 > --- a/Documentation/bpf/kfuncs.rst > +++ b/Documentation/bpf/kfuncs.rst > @@ -36,10 +36,12 @@ prototype in a header for the wrapper kfunc. > > An example is given below:: > > - /* Disables missing prototype warnings */ > + /* Disables missing prototypes and declarations warnings */ > __diag_push(); > __diag_ignore_all("-Wmissing-prototypes", > "Global kfuncs as their definitions will be in BTF"); > + __diag_ignore_all("-Wmissing-declarations", > + "Global kfuncs as their definitions will be in BTF"); > > __bpf_kfunc struct task_struct *bpf_find_get_task_by_vpid(pid_t nr) > { > diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c > index 96856f130cbf..b8def6e4e5e8 100644 > --- a/kernel/bpf/bpf_iter.c > +++ b/kernel/bpf/bpf_iter.c > @@ -785,6 +785,8 @@ struct bpf_iter_num_kern { > __diag_push(); > __diag_ignore_all("-Wmissing-prototypes", > "Global functions as their definitions will be in vmlinux BTF"); > +__diag_ignore_all("-Wmissing-declarations", > + "Global functions as their definitions will be in vmlinux BTF"); > > __bpf_kfunc int bpf_iter_num_new(struct bpf_iter_num *it, int start, int end) > { [...]
On Wed, Aug 16, 2023 at 8:38 PM Yonghong Song <yonghong.song@linux.dev> wrote: > > > > On 8/16/23 8:06 AM, David Vernet wrote: > > We recently got an lkp warning about missing declarations, as in e.g. > > [0]. This warning is largely redundant with -Wmissing-prototypes, which > > we already disable for kfuncs that have global linkage and are meant to > > be exported in BTF, and called from BPF programs. Let's also disable > > -Wmissing-declarations for kfuncs. For what it's worth, I wasn't able to > > reproduce the warning even on W <= 3, so I can't actually be 100% sure > > this fixes the issue. > > > > [0]: https://lore.kernel.org/all/202308162115.Hn23vv3n-lkp@intel.com/ > > Okay, I just got a similar email to [0] which complains > bpf_obj_new_impl, ..., bpf_cast_to_kern_ctx > missing declarations. > > In the email, the used compiler is > compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 > > Unfortunately, I did not have gcc-7 to verify this. > Also, what is the minimum gcc version kernel supports? 5.1? pahole and BTF might be broken in such old GCC too. Maybe we should add: config BPF_SYSCALL depends on GCC_VERSION >= 90000 || CLANG_VERSION >= 130000
On Wed, Aug 16, 2023 at 08:48:16PM -0700, Alexei Starovoitov wrote: > On Wed, Aug 16, 2023 at 8:38 PM Yonghong Song <yonghong.song@linux.dev> wrote: > > > > > > > > On 8/16/23 8:06 AM, David Vernet wrote: > > > We recently got an lkp warning about missing declarations, as in e.g. > > > [0]. This warning is largely redundant with -Wmissing-prototypes, which > > > we already disable for kfuncs that have global linkage and are meant to > > > be exported in BTF, and called from BPF programs. Let's also disable > > > -Wmissing-declarations for kfuncs. For what it's worth, I wasn't able to > > > reproduce the warning even on W <= 3, so I can't actually be 100% sure > > > this fixes the issue. > > > > > > [0]: https://lore.kernel.org/all/202308162115.Hn23vv3n-lkp@intel.com/ > > > > Okay, I just got a similar email to [0] which complains > > bpf_obj_new_impl, ..., bpf_cast_to_kern_ctx > > missing declarations. > > > > In the email, the used compiler is > > compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 > > > > Unfortunately, I did not have gcc-7 to verify this. > > Also, what is the minimum gcc version kernel supports? 5.1? > > pahole and BTF might be broken in such old GCC too. > Maybe we should add: > config BPF_SYSCALL > depends on GCC_VERSION >= 90000 || CLANG_VERSION >= 130000 It seems prudent to formally declare minimum compiler versions. Though modern gcc and clang also support -Wmissing-declarations, so maybe we should merge this patch regardless? Just unfortunate to have to add even more boilerplate just to get the compiler off our backs.
On 8/16/23 8:48 PM, Alexei Starovoitov wrote: > On Wed, Aug 16, 2023 at 8:38 PM Yonghong Song <yonghong.song@linux.dev> wrote: >> >> >> >> On 8/16/23 8:06 AM, David Vernet wrote: >>> We recently got an lkp warning about missing declarations, as in e.g. >>> [0]. This warning is largely redundant with -Wmissing-prototypes, which >>> we already disable for kfuncs that have global linkage and are meant to >>> be exported in BTF, and called from BPF programs. Let's also disable >>> -Wmissing-declarations for kfuncs. For what it's worth, I wasn't able to >>> reproduce the warning even on W <= 3, so I can't actually be 100% sure >>> this fixes the issue. >>> >>> [0]: https://lore.kernel.org/all/202308162115.Hn23vv3n-lkp@intel.com/ >> >> Okay, I just got a similar email to [0] which complains >> bpf_obj_new_impl, ..., bpf_cast_to_kern_ctx >> missing declarations. >> >> In the email, the used compiler is >> compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 >> >> Unfortunately, I did not have gcc-7 to verify this. >> Also, what is the minimum gcc version kernel supports? 5.1? > > pahole and BTF might be broken in such old GCC too. > Maybe we should add: > config BPF_SYSCALL > depends on GCC_VERSION >= 90000 || CLANG_VERSION >= 130000 Do you remember what kind of issues pahole/BTF have for < 9.0 gcc and < 13.0 clang?
On 8/17/23 6:01 AM, David Vernet wrote: > On Wed, Aug 16, 2023 at 08:48:16PM -0700, Alexei Starovoitov wrote: >> On Wed, Aug 16, 2023 at 8:38 PM Yonghong Song <yonghong.song@linux.dev> wrote: >>> On 8/16/23 8:06 AM, David Vernet wrote: >>>> We recently got an lkp warning about missing declarations, as in e.g. >>>> [0]. This warning is largely redundant with -Wmissing-prototypes, which >>>> we already disable for kfuncs that have global linkage and are meant to >>>> be exported in BTF, and called from BPF programs. Let's also disable >>>> -Wmissing-declarations for kfuncs. For what it's worth, I wasn't able to >>>> reproduce the warning even on W <= 3, so I can't actually be 100% sure >>>> this fixes the issue. >>>> >>>> [0]: https://lore.kernel.org/all/202308162115.Hn23vv3n-lkp@intel.com/ >>> >>> Okay, I just got a similar email to [0] which complains >>> bpf_obj_new_impl, ..., bpf_cast_to_kern_ctx >>> missing declarations. >>> >>> In the email, the used compiler is >>> compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 >>> >>> Unfortunately, I did not have gcc-7 to verify this. >>> Also, what is the minimum gcc version kernel supports? 5.1? >> >> pahole and BTF might be broken in such old GCC too. >> Maybe we should add: >> config BPF_SYSCALL >> depends on GCC_VERSION >= 90000 || CLANG_VERSION >= 130000 > > It seems prudent to formally declare minimum compiler versions. Though > modern gcc and clang also support -Wmissing-declarations, so maybe we > should merge this patch regardless? Just unfortunate to have to add even > more boilerplate just to get the compiler off our backs. Urgh, to restrict BPF syscall with such `depends on` would be super ugly. Why can't we just move this boilerplate behind a macro instead of copying this everywhere? For example the below on top of your patch builds just fine on my side: diff --git a/include/linux/btf.h b/include/linux/btf.h index df64cc642074..6a873a652001 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -83,6 +83,16 @@ */ #define __bpf_kfunc __used noinline +#define __bpf_kfunc_start \ + __diag_push(); \ + __diag_ignore_all("-Wmissing-prototypes", \ + "Global functions as their definitions will be in vmlinux BTF"); \ + __diag_ignore_all("-Wmissing-declarations", \ + "Global functions as their definitions will be in vmlinux BTF"); + +#define __bpf_kfunc_end \ + __diag_pop(); + /* * Return the name of the passed struct, if exists, or halt the build if for * example the structure gets renamed. In this way, developers have to revisit diff --git a/net/core/filter.c b/net/core/filter.c index c2b32b94c6bd..08dd0dd710dd 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -11724,11 +11724,7 @@ bpf_sk_base_func_proto(enum bpf_func_id func_id) return func; } -__diag_push(); -__diag_ignore_all("-Wmissing-prototypes", - "Global functions as their definitions will be in vmlinux BTF"); -__diag_ignore_all("-Wmissing-declarations", - "Global functions as their definitions will be in vmlinux BTF"); +__bpf_kfunc_start __bpf_kfunc int bpf_dynptr_from_skb(struct sk_buff *skb, u64 flags, struct bpf_dynptr_kern *ptr__uninit) { @@ -11754,7 +11750,7 @@ __bpf_kfunc int bpf_dynptr_from_xdp(struct xdp_buff *xdp, u64 flags, return 0; } -__diag_pop(); +__bpf_kfunc_end int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags, struct bpf_dynptr_kern *ptr__uninit) Thanks, Daniel
On Thu, Aug 17, 2023 at 04:35:26PM +0200, Daniel Borkmann wrote: > On 8/17/23 6:01 AM, David Vernet wrote: > > On Wed, Aug 16, 2023 at 08:48:16PM -0700, Alexei Starovoitov wrote: > > > On Wed, Aug 16, 2023 at 8:38 PM Yonghong Song <yonghong.song@linux.dev> wrote: > > > > On 8/16/23 8:06 AM, David Vernet wrote: > > > > > We recently got an lkp warning about missing declarations, as in e.g. > > > > > [0]. This warning is largely redundant with -Wmissing-prototypes, which > > > > > we already disable for kfuncs that have global linkage and are meant to > > > > > be exported in BTF, and called from BPF programs. Let's also disable > > > > > -Wmissing-declarations for kfuncs. For what it's worth, I wasn't able to > > > > > reproduce the warning even on W <= 3, so I can't actually be 100% sure > > > > > this fixes the issue. > > > > > > > > > > [0]: https://lore.kernel.org/all/202308162115.Hn23vv3n-lkp@intel.com/ > > > > > > > > Okay, I just got a similar email to [0] which complains > > > > bpf_obj_new_impl, ..., bpf_cast_to_kern_ctx > > > > missing declarations. > > > > > > > > In the email, the used compiler is > > > > compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 > > > > > > > > Unfortunately, I did not have gcc-7 to verify this. > > > > Also, what is the minimum gcc version kernel supports? 5.1? > > > > > > pahole and BTF might be broken in such old GCC too. > > > Maybe we should add: > > > config BPF_SYSCALL > > > depends on GCC_VERSION >= 90000 || CLANG_VERSION >= 130000 > > > > It seems prudent to formally declare minimum compiler versions. Though > > modern gcc and clang also support -Wmissing-declarations, so maybe we > > should merge this patch regardless? Just unfortunate to have to add even > > more boilerplate just to get the compiler off our backs. > > Urgh, to restrict BPF syscall with such `depends on` would be super ugly. Why > can't we just move this boilerplate behind a macro instead of copying this > everywhere? For example the below on top of your patch builds just fine on my > side: > > diff --git a/include/linux/btf.h b/include/linux/btf.h > index df64cc642074..6a873a652001 100644 > --- a/include/linux/btf.h > +++ b/include/linux/btf.h > @@ -83,6 +83,16 @@ > */ > #define __bpf_kfunc __used noinline > > +#define __bpf_kfunc_start \ > + __diag_push(); \ > + __diag_ignore_all("-Wmissing-prototypes", \ > + "Global functions as their definitions will be in vmlinux BTF"); \ > + __diag_ignore_all("-Wmissing-declarations", \ > + "Global functions as their definitions will be in vmlinux BTF"); > + This will not solve the robot's compain, as it fails on gcc7. The __diag_ignore_all for gcc is defined as #if GCC_VERSION >= 80000 #define __diag_GCC_8(s) __diag(s) #else #define __diag_GCC_8(s) #endif #define __diag_ignore_all(option, comment) \ __diag_GCC(8, ignore, option) so adding more __diag_ignore_all's will not do anything. This is better to patch __diag_ignore_all to include older gcc versions if anybody needs them. > +#define __bpf_kfunc_end \ > + __diag_pop(); > + > /* > * Return the name of the passed struct, if exists, or halt the build if for > * example the structure gets renamed. In this way, developers have to revisit > diff --git a/net/core/filter.c b/net/core/filter.c > index c2b32b94c6bd..08dd0dd710dd 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -11724,11 +11724,7 @@ bpf_sk_base_func_proto(enum bpf_func_id func_id) > return func; > } > > -__diag_push(); > -__diag_ignore_all("-Wmissing-prototypes", > - "Global functions as their definitions will be in vmlinux BTF"); > -__diag_ignore_all("-Wmissing-declarations", > - "Global functions as their definitions will be in vmlinux BTF"); > +__bpf_kfunc_start > __bpf_kfunc int bpf_dynptr_from_skb(struct sk_buff *skb, u64 flags, > struct bpf_dynptr_kern *ptr__uninit) > { > @@ -11754,7 +11750,7 @@ __bpf_kfunc int bpf_dynptr_from_xdp(struct xdp_buff *xdp, u64 flags, > > return 0; > } > -__diag_pop(); > +__bpf_kfunc_end > > int bpf_dynptr_from_skb_rdonly(struct sk_buff *skb, u64 flags, > struct bpf_dynptr_kern *ptr__uninit) > > Thanks, > Daniel
diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst index 0d2647fb358d..62ce5a7b92b4 100644 --- a/Documentation/bpf/kfuncs.rst +++ b/Documentation/bpf/kfuncs.rst @@ -36,10 +36,12 @@ prototype in a header for the wrapper kfunc. An example is given below:: - /* Disables missing prototype warnings */ + /* Disables missing prototypes and declarations warnings */ __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global kfuncs as their definitions will be in BTF"); + __diag_ignore_all("-Wmissing-declarations", + "Global kfuncs as their definitions will be in BTF"); __bpf_kfunc struct task_struct *bpf_find_get_task_by_vpid(pid_t nr) { diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index 96856f130cbf..b8def6e4e5e8 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -785,6 +785,8 @@ struct bpf_iter_num_kern { __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); __bpf_kfunc int bpf_iter_num_new(struct bpf_iter_num *it, int start, int end) { diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c index 6983af8e093c..111b0e062e7f 100644 --- a/kernel/bpf/cpumask.c +++ b/kernel/bpf/cpumask.c @@ -37,6 +37,8 @@ static bool cpu_valid(u32 cpu) __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global kfuncs as their definitions will be in BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global kfuncs as their definitions will be in BTF"); /** * bpf_cpumask_create() - Create a mutable BPF cpumask. diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index eb91cae0612a..6d2f84371892 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1885,6 +1885,8 @@ void bpf_rb_root_free(const struct btf_field *field, void *rb_root, __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); __bpf_kfunc void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign) { diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c index 6fc9dae9edc8..f7c7c5044630 100644 --- a/kernel/bpf/map_iter.c +++ b/kernel/bpf/map_iter.c @@ -196,6 +196,8 @@ late_initcall(bpf_map_iter_init); __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); __bpf_kfunc s64 bpf_map_sum_elem_count(const struct bpf_map *map) { diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c index 2542c21b6b6d..f5231a58ad3c 100644 --- a/kernel/cgroup/rstat.c +++ b/kernel/cgroup/rstat.c @@ -162,6 +162,8 @@ static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos, __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "kfuncs which will be used in BPF programs"); +__diag_ignore_all("-Wmissing-declarations", + "kfuncs which will be used in BPF programs"); __weak noinline void bpf_rstat_flush(struct cgroup *cgrp, struct cgroup *parent, int cpu) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 792445e1f3f0..1fa197aa428c 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1224,6 +1224,8 @@ static const struct bpf_func_proto bpf_get_func_arg_cnt_proto = { __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "kfuncs which will be used in BPF programs"); +__diag_ignore_all("-Wmissing-declarations", + "kfuncs which will be used in BPF programs"); /** * bpf_lookup_user_key - lookup a key by its serial diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 57a7a64b84ed..38aedb720a52 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -506,6 +506,8 @@ static int bpf_test_finish(const union bpf_attr *kattr, __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); __bpf_kfunc int bpf_fentry_test1(int a) { return a + 1; diff --git a/net/core/filter.c b/net/core/filter.c index a094694899c9..c2b32b94c6bd 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -11727,6 +11727,8 @@ bpf_sk_base_func_proto(enum bpf_func_id func_id) __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); __bpf_kfunc int bpf_dynptr_from_skb(struct sk_buff *skb, u64 flags, struct bpf_dynptr_kern *ptr__uninit) { @@ -11808,6 +11810,8 @@ late_initcall(bpf_kfunc_init); __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); /* bpf_sock_destroy: Destroy the given socket with ECONNABORTED error code. * diff --git a/net/core/xdp.c b/net/core/xdp.c index a70670fe9a2d..3d14e7be411d 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -699,6 +699,8 @@ struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf) __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in vmlinux BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in vmlinux BTF"); /** * bpf_xdp_metadata_rx_timestamp - Read XDP frame RX timestamp. diff --git a/net/ipv4/fou_bpf.c b/net/ipv4/fou_bpf.c index 3760a14b6b57..2b394703770a 100644 --- a/net/ipv4/fou_bpf.c +++ b/net/ipv4/fou_bpf.c @@ -25,6 +25,8 @@ enum bpf_fou_encap_type { __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in BTF"); /* bpf_skb_set_fou_encap - Set FOU encap parameters * diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c index c7a6114091ae..e24e2e4b2d49 100644 --- a/net/netfilter/nf_conntrack_bpf.c +++ b/net/netfilter/nf_conntrack_bpf.c @@ -233,6 +233,8 @@ static int _nf_conntrack_btf_struct_access(struct bpf_verifier_log *log, __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in nf_conntrack BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in nf_conntrack BTF"); /* bpf_xdp_ct_alloc - Allocate a new CT entry * diff --git a/net/netfilter/nf_nat_bpf.c b/net/netfilter/nf_nat_bpf.c index 141ee7783223..e903a6eb732e 100644 --- a/net/netfilter/nf_nat_bpf.c +++ b/net/netfilter/nf_nat_bpf.c @@ -15,6 +15,8 @@ __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in nf_nat BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in nf_nat BTF"); /* bpf_ct_set_nat_info - Set source or destination nat address * diff --git a/net/xfrm/xfrm_interface_bpf.c b/net/xfrm/xfrm_interface_bpf.c index d74f3fd20f2b..d40060bcc398 100644 --- a/net/xfrm/xfrm_interface_bpf.c +++ b/net/xfrm/xfrm_interface_bpf.c @@ -30,6 +30,8 @@ struct bpf_xfrm_info { __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in xfrm_interface BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in xfrm_interface BTF"); /* bpf_skb_get_xfrm_info - Get XFRM metadata * diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index cefc5dd72573..201a41cd47e5 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -42,6 +42,8 @@ struct bpf_testmod_struct_arg_4 { __diag_push(); __diag_ignore_all("-Wmissing-prototypes", "Global functions as their definitions will be in bpf_testmod.ko BTF"); +__diag_ignore_all("-Wmissing-declarations", + "Global functions as their definitions will be in bpf_testmod.ko BTF"); noinline int bpf_testmod_test_struct_arg_1(struct bpf_testmod_struct_arg_2 a, int b, int c) {
We recently got an lkp warning about missing declarations, as in e.g. [0]. This warning is largely redundant with -Wmissing-prototypes, which we already disable for kfuncs that have global linkage and are meant to be exported in BTF, and called from BPF programs. Let's also disable -Wmissing-declarations for kfuncs. For what it's worth, I wasn't able to reproduce the warning even on W <= 3, so I can't actually be 100% sure this fixes the issue. [0]: https://lore.kernel.org/all/202308162115.Hn23vv3n-lkp@intel.com/ Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202308162115.Hn23vv3n-lkp@intel.com/ Signed-off-by: David Vernet <void@manifault.com> --- Documentation/bpf/kfuncs.rst | 4 +++- kernel/bpf/bpf_iter.c | 2 ++ kernel/bpf/cpumask.c | 2 ++ kernel/bpf/helpers.c | 2 ++ kernel/bpf/map_iter.c | 2 ++ kernel/cgroup/rstat.c | 2 ++ kernel/trace/bpf_trace.c | 2 ++ net/bpf/test_run.c | 2 ++ net/core/filter.c | 4 ++++ net/core/xdp.c | 2 ++ net/ipv4/fou_bpf.c | 2 ++ net/netfilter/nf_conntrack_bpf.c | 2 ++ net/netfilter/nf_nat_bpf.c | 2 ++ net/xfrm/xfrm_interface_bpf.c | 2 ++ tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c | 2 ++ 15 files changed, 33 insertions(+), 1 deletion(-)