[PATCH bpf-next] selftests/bpf: Fix timer_start_deadlock failure due to hrtimer change

[Shung-Hsi Yu]

Since commit f2e388a019e4 ("hrtimer: Reduce trace noise in hrtimer_start()"),
hrtimer_cancel tracepoint is no longer called when a hrtimer is re-armed. So
instead of a hrtimer_cancel followed by hrtimer_start tracepoint events, there
is now only a since hrtimer_start tracepoint event with the new was_armed field
set to 1, to indicated that the hrtimer was previously armed.

Update timer_start_deadlock accordingly so it traces hrtimer_start tracepoint
instead, with was_armed used as guard.

Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@xxxxxxxx>
---
Currently only fails on Linus' tree since hrtimer changes haven't made
its way into bpf-next yet.
---
 tools/testing/selftests/bpf/progs/timer_start_deadlock.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/timer_start_deadlock.c b/tools/testing/selftests/bpf/progs/timer_start_deadlock.c
index 019518ee18cd..afabd15bdac4 100644
--- a/tools/testing/selftests/bpf/progs/timer_start_deadlock.c
+++ b/tools/testing/selftests/bpf/progs/timer_start_deadlock.c
@@ -27,13 +27,13 @@ static int timer_cb(void *map, int *key, struct elem *value)
 	return 0;
 }
 
-SEC("tp_btf/hrtimer_cancel")
-int BPF_PROG(tp_hrtimer_cancel, struct hrtimer *hrtimer)
+SEC("tp_btf/hrtimer_start")
+int BPF_PROG(tp_hrtimer_start, struct hrtimer *hrtimer, enum hrtimer_mode mode, bool was_armed)
 {
 	struct bpf_timer *timer;
 	int key = 0;
 
-	if (!in_timer_start)
+	if (!in_timer_start || !was_armed)
 		return 0;
 
 	tp_called = 1;
@@ -60,7 +60,7 @@ int start_timer(void *ctx)
 
 	/*
 	 * call hrtimer_start() twice, so that 2nd call does
-	 * remove_hrtimer() and trace_hrtimer_cancel() tracepoint.
+	 * trace_hrtimer_start(was_armed=1) tracepoint.
 	 */
 	in_timer_start = 1;
 	bpf_timer_start(timer, 1000000000, 0);
-- 
2.53.0