diff options
| author | Yonghong Song | 2017-10-23 23:53:08 -0700 |
|---|---|---|
| committer | David S. Miller | 2017-10-25 10:47:47 +0900 |
| commit | e87c6bc3852b981e71c757be20771546ce9f76f3 (patch) | |
| tree | bad3be630137d8e873f4ad5a1ea77b4aa1853184 /kernel/events | |
| 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/events')
| -rw-r--r-- | kernel/events/core.c | 26 |
1 files changed, 8 insertions, 18 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 9f78a6825bbe..9660ee65fbef 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7954,11 +7954,9 @@ void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, struct pt_regs *regs, struct hlist_head *head, struct task_struct *task) { - struct bpf_prog *prog = call->prog; - - if (prog) { + if (bpf_prog_array_valid(call)) { *(struct pt_regs **)raw_data = regs; - if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) { + if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) { perf_swevent_put_recursion_context(rctx); return; } @@ -8147,13 +8145,11 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) { bool is_kprobe, is_tracepoint, is_syscall_tp; struct bpf_prog *prog; + int ret; if (event->attr.type != PERF_TYPE_TRACEPOINT) return perf_event_set_bpf_handler(event, prog_fd); - if (event->tp_event->prog) - return -EEXIST; - is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE; is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; is_syscall_tp = is_syscall_trace_event(event->tp_event); @@ -8181,26 +8177,20 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) return -EACCES; } } - event->tp_event->prog = prog; - event->tp_event->bpf_prog_owner = event; - return 0; + ret = perf_event_attach_bpf_prog(event, prog); + if (ret) + bpf_prog_put(prog); + return ret; } static void perf_event_free_bpf_prog(struct perf_event *event) { - struct bpf_prog *prog; - if (event->attr.type != PERF_TYPE_TRACEPOINT) { perf_event_free_bpf_handler(event); return; } - - prog = event->tp_event->prog; - if (prog && event->tp_event->bpf_prog_owner == event) { - event->tp_event->prog = NULL; - bpf_prog_put(prog); - } + perf_event_detach_bpf_prog(event); } #else |