From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock 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 Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- fs/debugfs/internal.h | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 fs/debugfs/internal.h (limited to 'fs/debugfs/internal.h') diff --git a/fs/debugfs/internal.h b/fs/debugfs/internal.h new file mode 100644 index 000000000..c95699b27 --- /dev/null +++ b/fs/debugfs/internal.h @@ -0,0 +1,58 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * internal.h - declarations internal to debugfs + * + * Copyright (C) 2016 Nicolai Stange + */ + +#ifndef _DEBUGFS_INTERNAL_H_ +#define _DEBUGFS_INTERNAL_H_ +#include + +struct file_operations; + +struct debugfs_inode_info { + struct inode vfs_inode; + union { + const void *raw; + const struct file_operations *real_fops; + const struct debugfs_short_fops *short_fops; + debugfs_automount_t automount; + }; + void *aux; +}; + +static inline struct debugfs_inode_info *DEBUGFS_I(struct inode *inode) +{ + return container_of(inode, struct debugfs_inode_info, vfs_inode); +} + +/* declared over in file.c */ +extern const struct file_operations debugfs_noop_file_operations; +extern const struct file_operations debugfs_open_proxy_file_operations; +extern const struct file_operations debugfs_full_proxy_file_operations; +extern const struct file_operations debugfs_full_short_proxy_file_operations; + +struct debugfs_fsdata { + const struct file_operations *real_fops; + const struct debugfs_short_fops *short_fops; + struct { + refcount_t active_users; + struct completion active_users_drained; + + /* protect cancellations */ + struct mutex cancellations_mtx; + struct list_head cancellations; + unsigned int methods; + }; +}; + +enum { + HAS_READ = 1, + HAS_WRITE = 2, + HAS_LSEEK = 4, + HAS_POLL = 8, + HAS_IOCTL = 16 +}; + +#endif /* _DEBUGFS_INTERNAL_H_ */ -- cgit v1.3.1