From: Alexander Lobakin <alobakin@pm.me>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>
Cc: Alexander Lobakin <alobakin@pm.me>,
Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
Song Liu <songliubraving@fb.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 bpf 02/11] bpftool: define a local bpf_perf_link to fix accessing its fields
Date: Thu, 21 Apr 2022 00:38:58 +0000 [thread overview]
Message-ID: <20220421003152.339542-3-alobakin@pm.me> (raw)
In-Reply-To: <20220421003152.339542-1-alobakin@pm.me>
When building bpftool with !CONFIG_PERF_EVENTS:
skeleton/pid_iter.bpf.c:47:14: error: incomplete definition of type 'struct bpf_perf_link'
perf_link = container_of(link, struct bpf_perf_link, link);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:74:22: note: expanded from macro 'container_of'
((type *)(__mptr - offsetof(type, member))); \
^~~~~~~~~~~~~~~~~~~~~~
tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:68:60: note: expanded from macro 'offsetof'
#define offsetof(TYPE, MEMBER) ((unsigned long)&((TYPE *)0)->MEMBER)
~~~~~~~~~~~^
skeleton/pid_iter.bpf.c:44:9: note: forward declaration of 'struct bpf_perf_link'
struct bpf_perf_link *perf_link;
^
&bpf_perf_link is being defined and used only under the ifdef.
Define struct bpf_perf_link___local with the `preserve_access_index`
attribute inside the pid_iter BPF prog to allow compiling on any
configs. CO-RE will substitute it with the real struct bpf_perf_link
accesses later on.
container_of() is not CO-REd, but it is a noop for
bpf_perf_link <-> bpf_link and the local copy is a full mirror of
the original structure.
Fixes: cbdaf71f7e65 ("bpftool: Add bpf_cookie to link output")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
tools/bpf/bpftool/skeleton/pid_iter.bpf.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/tools/bpf/bpftool/skeleton/pid_iter.bpf.c b/tools/bpf/bpftool/skeleton/pid_iter.bpf.c
index e2af8e5fb29e..3a4c4f7d83d8 100644
--- a/tools/bpf/bpftool/skeleton/pid_iter.bpf.c
+++ b/tools/bpf/bpftool/skeleton/pid_iter.bpf.c
@@ -15,6 +15,11 @@ enum bpf_obj_type {
BPF_OBJ_BTF,
};
+struct bpf_perf_link___local {
+ struct bpf_link link;
+ struct file *perf_file;
+} __attribute__((preserve_access_index));
+
struct perf_event___local {
u64 bpf_cookie;
} __attribute__((preserve_access_index));
@@ -45,10 +50,10 @@ static __always_inline __u32 get_obj_id(void *ent, enum bpf_obj_type type)
/* could be used only with BPF_LINK_TYPE_PERF_EVENT links */
static __u64 get_bpf_cookie(struct bpf_link *link)
{
+ struct bpf_perf_link___local *perf_link;
struct perf_event___local *event;
- struct bpf_perf_link *perf_link;
- perf_link = container_of(link, struct bpf_perf_link, link);
+ perf_link = container_of(link, struct bpf_perf_link___local, link);
event = BPF_CORE_READ(perf_link, perf_file, private_data);
return BPF_CORE_READ(event, bpf_cookie);
}
--
2.36.0
next prev parent reply other threads:[~2022-04-21 0:39 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-21 0:38 [PATCH v2 bpf 00/11] bpf: random unpopular userspace fixes (32 bit et al) Alexander Lobakin
2022-04-21 0:38 ` [PATCH v2 bpf 01/11] bpftool: use a local copy of perf_event to fix accessing ::bpf_cookie Alexander Lobakin
2022-04-21 0:38 ` Alexander Lobakin [this message]
2023-04-14 9:54 ` [PATCH v2 bpf 02/11] bpftool: define a local bpf_perf_link to fix accessing its fields Michal Suchánek
2023-04-14 15:18 ` Alexander Lobakin
2023-04-14 16:28 ` Michal Suchánek
2023-04-20 23:07 ` Andrii Nakryiko
2023-04-21 7:39 ` Michal Suchánek
2023-05-03 23:43 ` Quentin Monnet
2023-05-03 23:52 ` Andrii Nakryiko
2023-05-04 8:18 ` Michal Suchánek
2023-05-04 16:48 ` Yonghong Song
2022-04-21 0:39 ` [PATCH v2 bpf 03/11] bpftool: use a local bpf_perf_event_value " Alexander Lobakin
2023-06-06 21:02 ` Nick Desaulniers
2023-06-07 10:42 ` Quentin Monnet
2023-06-07 16:18 ` Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 04/11] bpftool: fix fcntl.h include Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 05/11] samples/bpf: add 'asm/mach-generic' include path for every MIPS Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 06/11] samples/bpf: use host bpftool to generate vmlinux.h, not target Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 07/11] samples/bpf: fix uin64_t format literals Alexander Lobakin
2022-04-21 7:46 ` David Laight
2022-04-21 22:55 ` Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 08/11] samples/bpf: fix false-positive right-shift underflow warnings Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 09/11] samples/bpf: fix include order for non-Glibc environments Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 10/11] samples/bpf: fix -Wsequence-point Alexander Lobakin
2022-04-21 0:39 ` [PATCH v2 bpf 11/11] samples/bpf: xdpsock: fix -Wmaybe-uninitialized Alexander Lobakin
2022-04-21 0:40 ` [PATCH v2 bpf 00/11] bpf: random unpopular userspace fixes (32 bit et al) Alexei Starovoitov
2022-04-21 10:52 ` Toke Høiland-Jørgensen
2022-04-21 22:39 ` Alexander Lobakin
2022-04-21 23:17 ` Toke Høiland-Jørgensen
2022-05-03 21:17 ` Alexander Lobakin
2022-05-04 11:34 ` Toke Høiland-Jørgensen
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