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/romfs/internal.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 fs/romfs/internal.h (limited to 'fs/romfs/internal.h') diff --git a/fs/romfs/internal.h b/fs/romfs/internal.h new file mode 100644 index 000000000..e90df22bd --- /dev/null +++ b/fs/romfs/internal.h @@ -0,0 +1,43 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* RomFS internal definitions + * + * Copyright © 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include + +struct romfs_inode_info { + struct inode vfs_inode; + unsigned long i_metasize; /* size of non-data area */ + unsigned long i_dataoffset; /* from the start of fs */ +}; + +static inline size_t romfs_maxsize(struct super_block *sb) +{ + return (size_t) (unsigned long) sb->s_fs_info; +} + +static inline struct romfs_inode_info *ROMFS_I(struct inode *inode) +{ + return container_of(inode, struct romfs_inode_info, vfs_inode); +} + +/* + * mmap-nommu.c + */ +#if !defined(CONFIG_MMU) && defined(CONFIG_ROMFS_ON_MTD) +extern const struct file_operations romfs_ro_fops; +#else +#define romfs_ro_fops generic_ro_fops +#endif + +/* + * storage.c + */ +extern int romfs_dev_read(struct super_block *sb, unsigned long pos, + void *buf, size_t buflen); +extern ssize_t romfs_dev_strnlen(struct super_block *sb, + unsigned long pos, size_t maxlen); +extern int romfs_dev_strcmp(struct super_block *sb, unsigned long pos, + const char *str, size_t size); -- cgit v1.3.1