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, 101 insertions, 0 deletions

diff --git a/fs/ubifs/Kconfig b/fs/ubifs/Kconfig
new file mode 100644
index 000000000..45d3d207f
--- /dev/null
+++ b/fs/ubifs/Kconfig
@@ -0,0 +1,101 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config UBIFS_FS
+	tristate "UBIFS file system support"
+	select CRC16
+	select CRC32
+	select CRYPTO if UBIFS_FS_ADVANCED_COMPR
+	select CRYPTO if UBIFS_FS_LZO
+	select CRYPTO if UBIFS_FS_ZLIB
+	select CRYPTO if UBIFS_FS_ZSTD
+	select CRYPTO_LZO if UBIFS_FS_LZO
+	select CRYPTO_DEFLATE if UBIFS_FS_ZLIB
+	select CRYPTO_ZSTD if UBIFS_FS_ZSTD
+	select CRYPTO_HASH_INFO
+	select UBIFS_FS_XATTR if FS_ENCRYPTION
+	select FS_ENCRYPTION_ALGS if FS_ENCRYPTION
+	depends on MTD_UBI
+	help
+	  UBIFS is a file system for flash devices which works on top of UBI.
+
+if UBIFS_FS
+
+config UBIFS_FS_ADVANCED_COMPR
+	bool "Advanced compression options"
+	help
+	  This option allows to explicitly choose which compressions, if any,
+	  are enabled in UBIFS. Removing compressors means inability to read
+	  existing file systems.
+
+	  If unsure, say 'N'.
+
+config UBIFS_FS_LZO
+	bool "LZO compression support" if UBIFS_FS_ADVANCED_COMPR
+	default y
+	help
+	   LZO compressor is generally faster than zlib but compresses worse.
+	   Say 'Y' if unsure.
+
+config UBIFS_FS_ZLIB
+	bool "ZLIB compression support" if UBIFS_FS_ADVANCED_COMPR
+	default y
+	help
+	  Zlib compresses better than LZO but it is slower. Say 'Y' if unsure.
+
+config UBIFS_FS_ZSTD
+	bool "ZSTD compression support" if UBIFS_FS_ADVANCED_COMPR
+	depends on UBIFS_FS
+	default y
+	help
+	  ZSTD compresses is a big win in speed over Zlib and
+	  in compression ratio over LZO. Say 'Y' if unsure.
+
+config UBIFS_ATIME_SUPPORT
+	bool "Access time support"
+	default n
+	help
+	  Originally UBIFS did not support atime, because it looked like a bad idea due
+	  increased flash wear. This option adds atime support and it is disabled by default
+	  to preserve the old behavior. If you enable this option, UBIFS starts updating atime,
+	  which means that file-system read operations will cause writes (inode atime
+	  updates). This may affect file-system performance and increase flash device wear,
+	  so be careful. How often atime is updated depends on the selected strategy:
+	  strictatime is the "heavy", relatime is "lighter", etc.
+
+	  If unsure, say 'N'
+
+config UBIFS_FS_XATTR
+	bool "UBIFS XATTR support"
+	default y
+	help
+	  Saying Y here includes support for extended attributes (xattrs).
+	  Xattrs are name:value pairs associated with inodes by
+	  the kernel or by users (see the attr(5) manual page).
+
+	  If unsure, say Y.
+
+config UBIFS_FS_SECURITY
+	bool "UBIFS Security Labels"
+	depends on UBIFS_FS_XATTR
+	default y
+	help
+	  Security labels provide an access control facility to support Linux
+	  Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO
+	  Linux. This option enables an extended attribute handler for file
+	  security labels in the ubifs filesystem, so that it requires enabling
+	  the extended attribute support in advance.
+
+	  If you are not using a security module, say N.
+
+config UBIFS_FS_AUTHENTICATION
+	bool "UBIFS authentication support"
+	select KEYS
+	select CRYPTO_HMAC
+	select SYSTEM_DATA_VERIFICATION
+	help
+	  Enable authentication support for UBIFS. This feature offers protection
+	  against offline changes for both data and metadata of the filesystem.
+	  If you say yes here you should also select a hashing algorithm such as
+	  sha256, these are not selected automatically since there are many
+	  different options.
+
+endif # UBIFS_FS