[PATCHv2 bpf-next 1/4] bpf: Fix uprobe multi pid filter check

[Jiri Olsa]

Uprobe multi link does its own process (thread leader) filtering before
running the bpf program by comparing task's vm pointers.

But as Oleg pointed out there can be processes sharing the vm (CLONE_VM),
so we can't just compare task->vm pointers, but instead we need to use
same_thread_group call.

Suggested-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
 kernel/trace/bpf_trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index b69a39316c0c..98e395f1baae 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -3207,7 +3207,7 @@ static int uprobe_prog_run(struct bpf_uprobe *uprobe,
 	struct bpf_run_ctx *old_run_ctx;
 	int err = 0;
 
-	if (link->task && current->mm != link->task->mm)
+	if (link->task && !same_thread_group(current, link->task))
 		return 0;
 
 	if (sleepable)
-- 
2.46.0