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, 66 insertions, 0 deletions

diff --git a/fs/smb/server/misc.h b/fs/smb/server/misc.h
new file mode 100644
index 000000000..3909104e1
--- /dev/null
+++ b/fs/smb/server/misc.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
+ */
+
+#ifndef __KSMBD_MISC_H__
+#define __KSMBD_MISC_H__
+
+#ifdef CONFIG_PROC_FS
+#include <linux/proc_fs.h>
+#endif
+struct ksmbd_share_config;
+struct nls_table;
+struct kstat;
+struct ksmbd_file;
+
+int match_pattern(const char *str, size_t len, const char *pattern);
+int ksmbd_validate_filename(char *filename);
+int parse_stream_name(char *filename, char **stream_name, int *s_type);
+char *convert_to_nt_pathname(struct ksmbd_share_config *share,
+			     const struct path *path);
+int get_nlink(struct kstat *st);
+void ksmbd_conv_path_to_unix(char *path);
+void ksmbd_strip_last_slash(char *path);
+void ksmbd_conv_path_to_windows(char *path);
+char *ksmbd_casefold_sharename(struct unicode_map *um, const char *name);
+char *ksmbd_extract_sharename(struct unicode_map *um, const char *treename);
+
+#define KSMBD_DIR_INFO_ALIGNMENT	8
+struct ksmbd_dir_info;
+char *ksmbd_convert_dir_info_name(struct ksmbd_dir_info *d_info,
+				  const struct nls_table *local_nls,
+				  int *conv_len);
+
+#define NTFS_TIME_OFFSET	((u64)(369 * 365 + 89) * 24 * 3600 * 10000000)
+struct timespec64 ksmbd_NTtimeToUnix(__le64 ntutc);
+u64 ksmbd_UnixTimeToNT(struct timespec64 t);
+long long ksmbd_systime(void);
+
+#ifdef CONFIG_PROC_FS
+struct ksmbd_const_name {
+	unsigned int const_value;
+	const char *name;
+};
+
+void ksmbd_proc_init(void);
+void ksmbd_proc_cleanup(void);
+void ksmbd_proc_reset(void);
+struct proc_dir_entry *ksmbd_proc_create(const char *name,
+					 int (*show)(struct seq_file *m, void *v),
+			     void *v);
+void ksmbd_proc_show_flag_names(struct seq_file *m,
+				const struct ksmbd_const_name *table,
+				int count,
+				unsigned int flags);
+void ksmbd_proc_show_const_name(struct seq_file *m,
+				const char *format,
+				const struct ksmbd_const_name *table,
+				int count,
+				unsigned int const_value);
+#else
+static inline void ksmbd_proc_init(void) {}
+static inline void ksmbd_proc_cleanup(void) {}
+static inline void ksmbd_proc_reset(void) {}
+#endif
+#endif /* __KSMBD_MISC_H__ */