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authorJiri Olsa <jolsa@kernel.org>2024-04-30 13:28:24 +0200
committerAndrii Nakryiko <andrii@kernel.org>2024-04-30 09:45:53 -0700
commit535a3692ba7245792e6f23654507865d4293c850 (patch)
tree7352550565832f6ebad9e0e333c9857821e624dc
parent05cbc217aafbc631a6c2fab4accf95850cb48358 (diff)
bpf: Add support for kprobe session attach
Adding support to attach bpf program for entry and return probe of the same function. This is common use case which at the moment requires to create two kprobe multi links. Adding new BPF_TRACE_KPROBE_SESSION attach type that instructs kernel to attach single link program to both entry and exit probe. It's possible to control execution of the bpf program on return probe simply by returning zero or non zero from the entry bpf program execution to execute or not the bpf program on return probe respectively. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240430112830.1184228-2-jolsa@kernel.org
-rw-r--r--include/uapi/linux/bpf.h1
-rw-r--r--kernel/bpf/syscall.c7
-rw-r--r--kernel/trace/bpf_trace.c28
-rw-r--r--tools/include/uapi/linux/bpf.h1
4 files changed, 28 insertions, 9 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index d94a72593ead..90706a47f6ff 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1115,6 +1115,7 @@ enum bpf_attach_type {
BPF_CGROUP_UNIX_GETSOCKNAME,
BPF_NETKIT_PRIMARY,
BPF_NETKIT_PEER,
+ BPF_TRACE_KPROBE_SESSION,
__MAX_BPF_ATTACH_TYPE
};
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index f655adf42e39..13ad74ecf2cd 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4016,11 +4016,15 @@ static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog,
if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI &&
attach_type != BPF_TRACE_KPROBE_MULTI)
return -EINVAL;
+ if (prog->expected_attach_type == BPF_TRACE_KPROBE_SESSION &&
+ attach_type != BPF_TRACE_KPROBE_SESSION)
+ return -EINVAL;
if (prog->expected_attach_type == BPF_TRACE_UPROBE_MULTI &&
attach_type != BPF_TRACE_UPROBE_MULTI)
return -EINVAL;
if (attach_type != BPF_PERF_EVENT &&
attach_type != BPF_TRACE_KPROBE_MULTI &&
+ attach_type != BPF_TRACE_KPROBE_SESSION &&
attach_type != BPF_TRACE_UPROBE_MULTI)
return -EINVAL;
return 0;
@@ -5281,7 +5285,8 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
case BPF_PROG_TYPE_KPROBE:
if (attr->link_create.attach_type == BPF_PERF_EVENT)
ret = bpf_perf_link_attach(attr, prog);
- else if (attr->link_create.attach_type == BPF_TRACE_KPROBE_MULTI)
+ else if (attr->link_create.attach_type == BPF_TRACE_KPROBE_MULTI ||
+ attr->link_create.attach_type == BPF_TRACE_KPROBE_SESSION)
ret = bpf_kprobe_multi_link_attach(attr, prog);
else if (attr->link_create.attach_type == BPF_TRACE_UPROBE_MULTI)
ret = bpf_uprobe_multi_link_attach(attr, prog);
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 0ba722b57af3..06a9671834b6 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1631,6 +1631,17 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
}
}
+static bool is_kprobe_multi(const struct bpf_prog *prog)
+{
+ return prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI ||
+ prog->expected_attach_type == BPF_TRACE_KPROBE_SESSION;
+}
+
+static inline bool is_kprobe_session(const struct bpf_prog *prog)
+{
+ return prog->expected_attach_type == BPF_TRACE_KPROBE_SESSION;
+}
+
static const struct bpf_func_proto *
kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
{
@@ -1646,13 +1657,13 @@ kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
return &bpf_override_return_proto;
#endif
case BPF_FUNC_get_func_ip:
- if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI)
+ if (is_kprobe_multi(prog))
return &bpf_get_func_ip_proto_kprobe_multi;
if (prog->expected_attach_type == BPF_TRACE_UPROBE_MULTI)
return &bpf_get_func_ip_proto_uprobe_multi;
return &bpf_get_func_ip_proto_kprobe;
case BPF_FUNC_get_attach_cookie:
- if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI)
+ if (is_kprobe_multi(prog))
return &bpf_get_attach_cookie_proto_kmulti;
if (prog->expected_attach_type == BPF_TRACE_UPROBE_MULTI)
return &bpf_get_attach_cookie_proto_umulti;
@@ -2834,10 +2845,11 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,
void *data)
{
struct bpf_kprobe_multi_link *link;
+ int err;
link = container_of(fp, struct bpf_kprobe_multi_link, fp);
- kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
- return 0;
+ err = kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs);
+ return is_kprobe_session(link->link.prog) ? err : 0;
}
static void
@@ -2981,7 +2993,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
if (sizeof(u64) != sizeof(void *))
return -EOPNOTSUPP;
- if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI)
+ if (!is_kprobe_multi(prog))
return -EINVAL;
flags = attr->link_create.kprobe_multi.flags;
@@ -3062,10 +3074,10 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
if (err)
goto error;
- if (flags & BPF_F_KPROBE_MULTI_RETURN)
- link->fp.exit_handler = kprobe_multi_link_exit_handler;
- else
+ if (!(flags & BPF_F_KPROBE_MULTI_RETURN))
link->fp.entry_handler = kprobe_multi_link_handler;
+ if ((flags & BPF_F_KPROBE_MULTI_RETURN) || is_kprobe_session(prog))
+ link->fp.exit_handler = kprobe_multi_link_exit_handler;
link->addrs = addrs;
link->cookies = cookies;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index d94a72593ead..90706a47f6ff 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1115,6 +1115,7 @@ enum bpf_attach_type {
BPF_CGROUP_UNIX_GETSOCKNAME,
BPF_NETKIT_PRIMARY,
BPF_NETKIT_PEER,
+ BPF_TRACE_KPROBE_SESSION,
__MAX_BPF_ATTACH_TYPE
};