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/9p/cache.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 fs/9p/cache.h (limited to 'fs/9p/cache.h') diff --git a/fs/9p/cache.h b/fs/9p/cache.h new file mode 100644 index 000000000..ee1b6b06a --- /dev/null +++ b/fs/9p/cache.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * V9FS cache definitions. + * + * Copyright (C) 2009 by Abhishek Kulkarni + */ + +#ifndef _9P_CACHE_H +#define _9P_CACHE_H + +#ifdef CONFIG_9P_FSCACHE +#include + +extern int v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses, + const char *dev_name); + +extern void v9fs_cache_inode_get_cookie(struct inode *inode); + +#else /* CONFIG_9P_FSCACHE */ + +static inline void v9fs_cache_inode_get_cookie(struct inode *inode) +{ +} + +#endif /* CONFIG_9P_FSCACHE */ +#endif /* _9P_CACHE_H */ -- cgit v1.3.1