[PATCH bpf,perf]] bpf,perf: return EOPNOTSUPP for attaching bpf handler on PERF_COUNT_SW_DUMMY

[Florian Lehner]

At the moment it is not possible to attach a bpf handler to a perf event
of type PERF_TYPE_SOFTWARE with a configuration of PERF_COUNT_SW_DUMMY.

Signed-off-by: Florian Lehner <d...@der-flo.net>
---
 kernel/events/core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index da467e1dd49a..4e8846b7ceda 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9668,6 +9668,10 @@ static int perf_event_set_bpf_handler(struct perf_event 
*event, u32 prog_fd)
        if (event->prog)
                return -EEXIST;
 
+       if (event->attr.type == PERF_TYPE_SOFTWARE &&
+           event->attr.config == PERF_COUNT_SW_DUMMY)
+               return -EOPNOTSUPP;
+
        prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
        if (IS_ERR(prog))
                return PTR_ERR(prog);
-- 
2.28.0