kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:

    vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
    can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd

The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.

This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.

Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.

Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@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