xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

bpf: permit multiple bpf attachments for a single perf event

Browse Source 
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>
This commit is contained in:
Yonghong Song
2017-10-23 23:53:08 -07:00
committed by David S. Miller
parent 0b4c6841fe
commit e87c6bc385
9 changed files with 255 additions and 56 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
kernel/trace/trace_uprobe.c
View File

@@ -1113,13 +1113,12 @@ static void __uprobe_perf_func(struct trace_uprobe *tu,
{
struct trace_event_call *call = &tu->tp.call;
struct uprobe_trace_entry_head *entry;
struct bpf_prog *prog = call->prog;
struct hlist_head *head;
void *data;
int size, esize;
int rctx;
if (prog && !trace_call_bpf(prog, regs))
if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
return;
esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));