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, 74 insertions, 0 deletions

diff --git a/fs/smb/server/Kconfig b/fs/smb/server/Kconfig
new file mode 100644
index 000000000..08d8b7a96
--- /dev/null
+++ b/fs/smb/server/Kconfig
@@ -0,0 +1,74 @@
+config SMB_SERVER
+	tristate "SMB3 server support"
+	depends on INET
+	depends on MULTIUSER
+	depends on FILE_LOCKING
+	select NLS
+	select NLS_UTF8
+	select NLS_UCS2_UTILS
+	select CRYPTO
+	select CRYPTO_LIB_AES_CBC_MACS
+	select CRYPTO_LIB_ARC4
+	select CRYPTO_LIB_DES
+	select CRYPTO_LIB_MD5
+	select CRYPTO_LIB_SHA256
+	select CRYPTO_LIB_SHA512
+	select CRYPTO_LIB_UTILS
+	select CRYPTO_AEAD2
+	select CRYPTO_CCM
+	select CRYPTO_GCM
+	select ASN1
+	select OID_REGISTRY
+	select CRC32
+	default n
+	help
+	  Choose Y here if you want to allow SMB3 compliant clients
+	  to access files residing on this system using SMB3 protocol.
+	  To compile the SMB3 server support as a module,
+	  choose M here: the module will be called ksmbd.
+
+	  You may choose to use a samba server instead, in which
+	  case you can choose N here.
+
+	  You also need to install user space programs which can be found
+	  in ksmbd-tools, available from
+	  https://github.com/cifsd-team/ksmbd-tools.
+	  More detail about how to run the ksmbd kernel server is
+	  available via the README file
+	  (https://github.com/cifsd-team/ksmbd-tools/blob/master/README).
+
+	  ksmbd kernel server includes support for auto-negotiation,
+	  Secure negotiate, Pre-authentication integrity, oplock/lease,
+	  compound requests, multi-credit, packet signing, RDMA(smbdirect),
+	  smb3 encryption, copy-offload, secure per-user session
+	  establishment via Kerberos or NTLMv2.
+
+if SMB_SERVER
+
+config SMB_SERVER_SMBDIRECT
+	bool "Support for SMB Direct protocol"
+	depends on SMB_SERVER && INFINIBAND && INFINIBAND_ADDR_TRANS
+	depends on SMB_SERVER=m || INFINIBAND=y
+	select SMBDIRECT
+	default n
+
+	help
+	  Enables SMB Direct support for SMB 3.0, 3.02 and 3.1.1.
+
+	  SMB Direct allows transferring SMB packets over RDMA. If unsure,
+	  say N.
+
+endif
+
+config SMB_SERVER_CHECK_CAP_NET_ADMIN
+	bool "Enable check network administration capability"
+	depends on SMB_SERVER
+	default y
+
+	help
+	  Prevent unprivileged processes to start the ksmbd kernel server.
+
+config SMB_SERVER_KERBEROS5
+	bool "Support for Kerberos 5"
+	depends on SMB_SERVER
+	default y