diff options
| author | Yonghong Song <yhs@fb.com> | 2017-10-23 23:53:08 -0700 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2022-04-19 00:51:32 +0300 |
| commit | a85b6c28bb287439916716f124450ceb79a1624f (patch) | |
| tree | faa8839e1d97bcd06a42bc681f86df74734d02fb /kernel/events | |
| parent | 3f79f14b62202045de323c754352cee2ac3b1d08 (diff) | |
BACKPORT: 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>
(cherry picked from commit e87c6bc3852b981e71c757be20771546ce9f76f3)
Signed-off-by: Connor O'Brien <connoro@google.com>
Bug: 121213201
Bug: 138317270
Test: build & boot cuttlefish; attach 2 progs to 1 tracepoint
Change-Id: I390d8c0146888ddb1aed5a6f6e5dae7ef394ebc9
Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
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 3c03da137864..470cb4cb8f74 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7203,11 +7203,9 @@ 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; } @@ -7410,6 +7408,7 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) { bool is_kprobe, is_tracepoint; struct bpf_prog *prog; + int ret; if (event->attr.type == PERF_TYPE_HARDWARE || event->attr.type == PERF_TYPE_SOFTWARE) @@ -7418,9 +7417,6 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) if (event->attr.type != PERF_TYPE_TRACEPOINT) return -EINVAL; - 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; if (!is_kprobe && !is_tracepoint) @@ -7446,26 +7442,20 @@ 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 |