diff options
| author | Yonghong Song <yhs@fb.com> | 2017-10-23 23:53:08 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-10-25 10:47:47 +0900 |
| commit | e87c6bc3852b981e71c757be20771546ce9f76f3 (patch) | |
| tree | bad3be630137d8e873f4ad5a1ea77b4aa1853184 /kernel/trace/trace_kprobe.c | |
| parent | 0b4c6841fee03e096b735074a0c4aab3a8e92986 (diff) | |
bpf: permit multiple bpf attachments for a single perf event
This patch enables multiple bpf attachments for a
kprobe/uprobe/tracepoint single trace event.
Each trace_event keeps a list of attached perf events.
When an event happens, all attached bpf programs will
be executed based on the order of attachment.
A global bpf_event_mutex lock is introduced to protect
prog_array attaching and detaching. An alternative will
be introduce a mutex lock in every trace_event_call
structure, but it takes a lot of extra memory.
So a global bpf_event_mutex lock is a good compromise.
The bpf prog detachment involves allocation of memory.
If the allocation fails, a dummy do-nothing program
will replace to-be-detached program in-place.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/trace/trace_kprobe.c')
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 8a907e12b6b9..abf92e478cfb 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1174,13 +1174,12 @@ static void kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) { struct trace_event_call *call = &tk->tp.call; - struct bpf_prog *prog = call->prog; struct kprobe_trace_entry_head *entry; struct hlist_head *head; int size, __size, dsize; int rctx; - if (prog && !trace_call_bpf(prog, regs)) + if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) return; head = this_cpu_ptr(call->perf_events); @@ -1210,13 +1209,12 @@ kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, struct pt_regs *regs) { struct trace_event_call *call = &tk->tp.call; - struct bpf_prog *prog = call->prog; struct kretprobe_trace_entry_head *entry; struct hlist_head *head; int size, __size, dsize; int rctx; - if (prog && !trace_call_bpf(prog, regs)) + if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) return; head = this_cpu_ptr(call->perf_events); |