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, 30 insertions, 0 deletions

diff --git a/include/soc/mediatek/smi.h b/include/soc/mediatek/smi.h
new file mode 100644
index 000000000..000eb1cf6
--- /dev/null
+++ b/include/soc/mediatek/smi.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2015-2016 MediaTek Inc.
+ * Author: Yong Wu <yong.wu@mediatek.com>
+ */
+#ifndef MTK_IOMMU_SMI_H
+#define MTK_IOMMU_SMI_H
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+
+#if IS_ENABLED(CONFIG_MTK_SMI)
+
+enum iommu_atf_cmd {
+	IOMMU_ATF_CMD_CONFIG_SMI_LARB,		/* For mm master to en/disable iommu */
+	IOMMU_ATF_CMD_CONFIG_INFRA_IOMMU,	/* For infra master to enable iommu */
+	IOMMU_ATF_CMD_MAX,
+};
+
+#define MTK_SMI_MMU_EN(port)	BIT(port)
+
+struct mtk_smi_larb_iommu {
+	struct device *dev;
+	unsigned int   mmu;
+	unsigned char  bank[32];
+};
+
+#endif
+
+#endif