From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andriin@fb.com>
Cc: "kernel test robot" <lkp@intel.com>,
"Julia Lawall" <julia.lawall@lip6.fr>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
"Martin KaFai Lau" <kafai@fb.com>,
"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
"John Fastabend" <john.fastabend@gmail.com>,
"KP Singh" <kpsingh@chromium.org>,
"Julia Lawall" <julia.lawall@inria.fr>
Subject: [PATCHv5 bpf-next 1/7] bpf: Allow trampoline re-attach for tracing and lsm programs
Date: Wed, 14 Apr 2021 21:51:41 +0200 [thread overview]
Message-ID: <20210414195147.1624932-2-jolsa@kernel.org> (raw)
In-Reply-To: <20210414195147.1624932-1-jolsa@kernel.org>
Currently we don't allow re-attaching of trampolines. Once
it's detached, it can't be re-attach even when the program
is still loaded.
Adding the possibility to re-attach the loaded tracing and
lsm programs.
Fixing missing unlock with proper cleanup goto jump reported
by Julia.
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/bpf/syscall.c | 23 +++++++++++++++++------
kernel/bpf/trampoline.c | 4 ++--
2 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index fd495190115e..941ca06d9dfa 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2648,14 +2648,25 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
* target_btf_id using the link_create API.
*
* - if tgt_prog == NULL when this function was called using the old
- * raw_tracepoint_open API, and we need a target from prog->aux
- *
- * The combination of no saved target in prog->aux, and no target
- * specified on load is illegal, and we reject that here.
+ * raw_tracepoint_open API, and we need a target from prog->aux
+ *
+ * - if prog->aux->dst_trampoline and tgt_prog is NULL, the program
+ * was detached and is going for re-attachment.
*/
if (!prog->aux->dst_trampoline && !tgt_prog) {
- err = -ENOENT;
- goto out_unlock;
+ /*
+ * Allow re-attach for TRACING and LSM programs. If it's
+ * currently linked, bpf_trampoline_link_prog will fail.
+ * EXT programs need to specify tgt_prog_fd, so they
+ * re-attach in separate code path.
+ */
+ if (prog->type != BPF_PROG_TYPE_TRACING &&
+ prog->type != BPF_PROG_TYPE_LSM) {
+ err = -EINVAL;
+ goto out_unlock;
+ }
+ btf_id = prog->aux->attach_btf_id;
+ key = bpf_trampoline_compute_key(NULL, prog->aux->attach_btf, btf_id);
}
if (!prog->aux->dst_trampoline ||
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 1f3a4be4b175..205c2cc36ad7 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -414,7 +414,7 @@ int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr)
tr->progs_cnt[kind]++;
err = bpf_trampoline_update(tr);
if (err) {
- hlist_del(&prog->aux->tramp_hlist);
+ hlist_del_init(&prog->aux->tramp_hlist);
tr->progs_cnt[kind]--;
}
out:
@@ -437,7 +437,7 @@ int bpf_trampoline_unlink_prog(struct bpf_prog *prog, struct bpf_trampoline *tr)
tr->extension_prog = NULL;
goto out;
}
- hlist_del(&prog->aux->tramp_hlist);
+ hlist_del_init(&prog->aux->tramp_hlist);
tr->progs_cnt[kind]--;
err = bpf_trampoline_update(tr);
out:
--
2.30.2
next prev parent reply other threads:[~2021-04-14 19:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 19:51 [PATCHv5 bpf-next 0/7] bpf: Tracing and lsm programs re-attach Jiri Olsa
2021-04-14 19:51 ` Jiri Olsa [this message]
2021-04-15 23:22 ` [PATCHv5 bpf-next 1/7] bpf: Allow trampoline re-attach for tracing and lsm programs Andrii Nakryiko
2021-04-19 22:47 ` KP Singh
2021-04-14 19:51 ` [PATCHv5 bpf-next 2/7] selftests/bpf: Add missing semicolon Jiri Olsa
2021-04-15 23:23 ` Andrii Nakryiko
2021-04-14 19:51 ` [PATCHv5 bpf-next 3/7] selftests/bpf: Add re-attach test to fentry_test Jiri Olsa
2021-04-14 19:51 ` [PATCHv5 bpf-next 4/7] selftests/bpf: Add re-attach test to fexit_test Jiri Olsa
2021-04-14 19:51 ` [PATCHv5 bpf-next 5/7] selftests/bpf: Add re-attach test to lsm test Jiri Olsa
2021-04-14 19:51 ` [PATCHv5 bpf-next 6/7] selftests/bpf: Test that module can't be unloaded with attached trampoline Jiri Olsa
2021-04-14 19:51 ` [PATCHv5 bpf-next 7/7] selftests/bpf: Use ASSERT macros in lsm test Jiri Olsa
2021-04-15 23:24 ` Andrii Nakryiko
2021-04-15 23:45 ` [PATCHv5 bpf-next 0/7] bpf: Tracing and lsm programs re-attach Alexei Starovoitov
2021-04-16 6:55 ` Jiri Olsa
2021-04-26 4:14 ` Alexei Starovoitov
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