[PATCH blktests] nvme/070: add a test for Identify CNS 07h NULL pointer dereference

[Guixin Liu <kanie@linux.alibaba.com>]

nvmet_execute_identify_nslist() handles both the Active Namespace ID list
(CNS 02h) and the per-command-set variant (CNS 07h). For CNS 07h it
filtered the list on req->ns->csi, but this handler never resolves
req->ns, so it is always NULL. As soon as an enabled namespace with an
NSID above the requested value exists, the target dereferenced a NULL
pointer and oopsed.

This test connects a target with a single namespace and issues an
Identify with CNS 07h starting from NSID 0, which is exactly the
condition that triggered the crash. Without the kernel fix [0] the target
oopses; with it the command completes normally.

[0] https://lore.kernel.org/linux-nvme/20260730043105.3071328-2-kanie@linux.alibaba.com/

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
---
 tests/nvme/070     | 54 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/nvme/070.out |  2 ++
 2 files changed, 56 insertions(+)
 create mode 100755 tests/nvme/070
 create mode 100644 tests/nvme/070.out

diff --git a/tests/nvme/070 b/tests/nvme/070
new file mode 100755
index 0000000..1f29a69
--- /dev/null
+++ b/tests/nvme/070
@@ -0,0 +1,54 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-3.0+
+# Copyright (C) 2026 Guixin Liu
+#
+# Regression test for the NULL pointer dereference in
+# nvmet_execute_identify_nslist() when handling Identify CNS 07h (Active
+# Namespace ID List for the specified I/O Command Set). The CNS 07h handler
+# filtered the list on req->ns->csi, but this handler never resolves req->ns
+# so it is always NULL. As soon as an enabled namespace with an NSID above the
+# requested value exists, the target dereferenced a NULL pointer and oopsed.
+
+. tests/nvme/rc
+
+DESCRIPTION="issue Identify CNS 07h (per-command-set active NS list)"
+QUICK=1
+
+requires() {
+	_nvme_requires
+	_have_loop
+	_require_nvme_trtype_is_fabrics
+}
+
+set_conditions() {
+	_set_nvme_trtype "$@"
+}
+
+test() {
+	echo "Running ${TEST_NAME}"
+
+	_setup_nvmet
+
+	_nvmet_target_setup
+
+	_nvme_connect_subsys
+
+	local nvmedev
+	nvmedev=$(_find_nvme_dev "${def_subsysnqn}")
+
+	# CNS 07h == Active Namespace ID list for the specified I/O Command Set.
+	# CDW10 bits[7:0] hold the CNS; CDW11 bits[31:24] hold the CSI (0 == NVM).
+	# Request from NSID 0 so the enabled namespace (NSID 1) is listed, which
+	# is exactly the condition that used to dereference the NULL req->ns.
+	if ! nvme admin-passthru "/dev/${nvmedev}" --opcode=0x06 \
+		--namespace-id=0 --cdw10=0x07 --cdw11=0 --data-len=4096 -r \
+		>> "${FULL}" 2>&1; then
+		echo "Error: Identify CNS 07h failed"
+	fi
+
+	_nvme_disconnect_subsys
+
+	_nvmet_target_cleanup
+
+	echo "Test complete"
+}
diff --git a/tests/nvme/070.out b/tests/nvme/070.out
new file mode 100644
index 0000000..b765a28
--- /dev/null
+++ b/tests/nvme/070.out
@@ -0,0 +1,2 @@
+Running nvme/070
+Test complete
-- 
2.43.7