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, 48 insertions, 0 deletions

diff --git a/rust/helpers/security.c b/rust/helpers/security.c
new file mode 100644
index 000000000..8d0a25fcf
--- /dev/null
+++ b/rust/helpers/security.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/security.h>
+
+#ifndef CONFIG_SECURITY
+__rust_helper void rust_helper_security_cred_getsecid(const struct cred *c,
+						      u32 *secid)
+{
+	security_cred_getsecid(c, secid);
+}
+
+__rust_helper int rust_helper_security_secid_to_secctx(u32 secid,
+						       struct lsm_context *cp)
+{
+	return security_secid_to_secctx(secid, cp);
+}
+
+__rust_helper void rust_helper_security_release_secctx(struct lsm_context *cp)
+{
+	security_release_secctx(cp);
+}
+
+__rust_helper int
+rust_helper_security_binder_set_context_mgr(const struct cred *mgr)
+{
+	return security_binder_set_context_mgr(mgr);
+}
+
+__rust_helper int
+rust_helper_security_binder_transaction(const struct cred *from,
+					const struct cred *to)
+{
+	return security_binder_transaction(from, to);
+}
+
+__rust_helper int
+rust_helper_security_binder_transfer_binder(const struct cred *from,
+					    const struct cred *to)
+{
+	return security_binder_transfer_binder(from, to);
+}
+
+__rust_helper int rust_helper_security_binder_transfer_file(
+	const struct cred *from, const struct cred *to, const struct file *file)
+{
+	return security_binder_transfer_file(from, to, file);
+}
+#endif