selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/drivers/target/Kconfig b/drivers/target/Kconfig
new file mode 100644
index 000000000..92641d391
--- /dev/null
+++ b/drivers/target/Kconfig
@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+menuconfig TARGET_CORE
+	tristate "Generic Target Core Mod (TCM) and ConfigFS Infrastructure"
+	depends on BLOCK
+	select CONFIGFS_FS
+	select CRC_T10DIF
+	select SCSI_COMMON
+	select SGL_ALLOC
+	default n
+	help
+	Say Y or M here to enable the TCM Storage Engine and ConfigFS enabled
+	control path for target_core_mod.  This includes built-in TCM RAMDISK
+	subsystem logic for virtual LUN 0 access
+
+if TARGET_CORE
+
+config TCM_IBLOCK
+	tristate "TCM/IBLOCK Subsystem Plugin for Linux/BLOCK"
+	select BLK_DEV_INTEGRITY
+	help
+	Say Y here to enable the TCM/IBLOCK subsystem plugin for non-buffered
+	access to Linux/Block devices using BIO
+
+config TCM_FILEIO
+	tristate "TCM/FILEIO Subsystem Plugin for Linux/VFS"
+	help
+	Say Y here to enable the TCM/FILEIO subsystem plugin for buffered
+	access to Linux/VFS struct file or struct block_device
+
+config TCM_PSCSI
+	tristate "TCM/pSCSI Subsystem Plugin for Linux/SCSI"
+	depends on SCSI
+	help
+	Say Y here to enable the TCM/pSCSI subsystem plugin for non-buffered
+	passthrough access to Linux/SCSI device
+
+config TCM_USER2
+	tristate "TCM/USER Subsystem Plugin for Linux"
+	depends on UIO && NET
+	help
+	Say Y here to enable the TCM/USER subsystem plugin for a userspace
+	process to handle requests. This is version 2 of the ABI; version 1
+	is obsolete.
+
+source "drivers/target/loopback/Kconfig"
+source "drivers/target/tcm_fc/Kconfig"
+source "drivers/target/iscsi/Kconfig"
+source "drivers/target/sbp/Kconfig"
+source "drivers/target/tcm_remote/Kconfig"
+
+endif