selftests/bpf: Test rhtab kptr cancellation semanticsgrafted

Resizable hash-map updates and deletions must not perform full special-field
destruction in their caller context. In particular, a referenced kptr must
remain attached to the allocation until the memory allocator destructor can
release it safely.

Add separate coverage for both affected paths. The update test stores a task
kptr, replaces the ordinary value bytes with BPF_EXIST, and verifies that the
kptr survived. The delete test removes an element and exchanges its kptr
through the still-valid map-value pointer before the allocation is reclaimed.

Both cases observe a NULL kptr when rhtab uses bpf_obj_free_fields(). They
recover and release the reference after rhtab switches to cancellation
semantics.

Signed-off-by: Nuoqi Gui <gnq25@mails.tsinghua.edu.cn>
[ kkd: Split update and delete coverage and rewrote the commit log ]
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904104203.345917-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 47 insertions, 0 deletions

diff --git a/tools/perf/ui/progress.c b/tools/perf/ui/progress.c
new file mode 100644
index 000000000..99d60223c
--- /dev/null
+++ b/tools/perf/ui/progress.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include "progress.h"
+
+static void null_progress__update(struct ui_progress *p __maybe_unused)
+{
+}
+
+static struct ui_progress_ops null_progress__ops =
+{
+	.update = null_progress__update,
+};
+
+struct ui_progress_ops *ui_progress__ops = &null_progress__ops;
+
+void ui_progress__update(struct ui_progress *p, u64 adv)
+{
+	u64 last = p->curr;
+
+	p->curr += adv;
+
+	if (p->curr >= p->next) {
+		u64 nr = DIV_ROUND_UP(p->curr - last, p->step);
+
+		p->next += nr * p->step;
+		ui_progress__ops->update(p);
+	}
+}
+
+void __ui_progress__init(struct ui_progress *p, u64 total,
+			 const char *title, bool size)
+{
+	p->curr = 0;
+	p->next = p->step = total / 16 ?: 1;
+	p->total = total;
+	p->title = title;
+	p->size  = size;
+
+	if (ui_progress__ops->init)
+		ui_progress__ops->init(p);
+}
+
+void ui_progress__finish(void)
+{
+	if (ui_progress__ops->finish)
+		ui_progress__ops->finish();
+}