selftests/bpf: Add a test for objects stuck in free_by_rcu_ttracegrafted

Delete all elements of BPF_F_NO_PREALLOC hash map in one batch. The first
free_bulk() starts RCU tasks trace GP and the rest of the elements are
freed while it's in flight. Wait for call_rcu_ttrace_in_progress to clear
in bpf_mem_cache of every cpu and check that free_by_rcu_ttrace and
waiting_for_gp_ttrace lists are empty.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20260930095920.601738-4-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 136 insertions, 0 deletions

diff --git a/include/trace/events/ipi.h b/include/trace/events/ipi.h
new file mode 100644
index 000000000..fae4f8eac
--- /dev/null
+++ b/include/trace/events/ipi.h
@@ -0,0 +1,136 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM ipi
+
+#if !defined(_TRACE_IPI_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_IPI_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(ipi_send_cpu,
+
+	TP_PROTO(const unsigned int cpu, unsigned long callsite, void *callback),
+
+	TP_ARGS(cpu, callsite, callback),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, cpu)
+		__field(void *, callsite)
+		__field(void *, callback)
+	),
+
+	TP_fast_assign(
+		__entry->cpu = cpu;
+		__entry->callsite = (void *)callsite;
+		__entry->callback = callback;
+	),
+
+	TP_printk("cpu=%u callsite=%pS callback=%pS",
+		  __entry->cpu, __entry->callsite, __entry->callback)
+);
+
+TRACE_EVENT(ipi_send_cpumask,
+
+	TP_PROTO(const struct cpumask *cpumask, unsigned long callsite, void *callback),
+
+	TP_ARGS(cpumask, callsite, callback),
+
+	TP_STRUCT__entry(
+		__cpumask(cpumask)
+		__field(void *, callsite)
+		__field(void *, callback)
+	),
+
+	TP_fast_assign(
+		__assign_cpumask(cpumask, cpumask_bits(cpumask));
+		__entry->callsite = (void *)callsite;
+		__entry->callback = callback;
+	),
+
+	TP_printk("cpumask=%s callsite=%pS callback=%pS",
+		  __get_cpumask(cpumask), __entry->callsite, __entry->callback)
+);
+
+#ifdef CONFIG_HAVE_EXTRA_IPI_TRACEPOINTS
+/**
+ * ipi_raise - called when a smp cross call is made
+ *
+ * @mask: mask of recipient CPUs for the IPI
+ * @reason: string identifying the IPI purpose
+ *
+ * It is necessary for @reason to be a static string declared with
+ * __tracepoint_string.
+ */
+TRACE_EVENT(ipi_raise,
+
+	TP_PROTO(const struct cpumask *mask, const char *reason),
+
+	TP_ARGS(mask, reason),
+
+	TP_STRUCT__entry(
+		__cpumask(target_cpus)
+		__field(const char *, reason)
+	),
+
+	TP_fast_assign(
+		__assign_cpumask(target_cpus, cpumask_bits(mask));
+		__entry->reason = reason;
+	),
+
+	TP_printk("target_mask=%s (%s)", __get_cpumask(target_cpus), __entry->reason)
+);
+
+DECLARE_EVENT_CLASS(ipi_handler,
+
+	TP_PROTO(const char *reason),
+
+	TP_ARGS(reason),
+
+	TP_STRUCT__entry(
+		__field(const char *, reason)
+	),
+
+	TP_fast_assign(
+		__entry->reason = reason;
+	),
+
+	TP_printk("(%s)", __entry->reason)
+);
+
+/**
+ * ipi_entry - called immediately before the IPI handler
+ *
+ * @reason: string identifying the IPI purpose
+ *
+ * It is necessary for @reason to be a static string declared with
+ * __tracepoint_string, ideally the same as used with trace_ipi_raise
+ * for that IPI.
+ */
+DEFINE_EVENT(ipi_handler, ipi_entry,
+
+	TP_PROTO(const char *reason),
+
+	TP_ARGS(reason)
+);
+
+/**
+ * ipi_exit - called immediately after the IPI handler returns
+ *
+ * @reason: string identifying the IPI purpose
+ *
+ * It is necessary for @reason to be a static string declared with
+ * __tracepoint_string, ideally the same as used with trace_ipi_raise for
+ * that IPI.
+ */
+DEFINE_EVENT(ipi_handler, ipi_exit,
+
+	TP_PROTO(const char *reason),
+
+	TP_ARGS(reason)
+);
+#endif /* CONFIG_HAVE_EXTRA_IPI_TRACEPOINTS */
+
+#endif /* _TRACE_IPI_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>