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/notify/inotify/inotify.h | 69 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 fs/notify/inotify/inotify.h (limited to 'fs/notify/inotify/inotify.h') diff --git a/fs/notify/inotify/inotify.h b/fs/notify/inotify/inotify.h new file mode 100644 index 000000000..7d5df7a21 --- /dev/null +++ b/fs/notify/inotify/inotify.h @@ -0,0 +1,69 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include +#include +#include /* struct kmem_cache */ + +struct inotify_event_info { + struct fsnotify_event fse; + u32 mask; + int wd; + u32 sync_cookie; + int name_len; + char name[]; +}; + +struct inotify_inode_mark { + struct fsnotify_mark fsn_mark; + int wd; +}; + +static inline struct inotify_event_info *INOTIFY_E(struct fsnotify_event *fse) +{ + return container_of(fse, struct inotify_event_info, fse); +} + +/* + * INOTIFY_USER_FLAGS represents all of the mask bits that we expose to + * userspace. There is at least one bit (FS_EVENT_ON_CHILD) which is + * used only internally to the kernel. + */ +#define INOTIFY_USER_MASK (IN_ALL_EVENTS) + +static inline __u32 inotify_mark_user_mask(struct fsnotify_mark *fsn_mark) +{ + __u32 mask = fsn_mark->mask & INOTIFY_USER_MASK; + + if (fsn_mark->flags & FSNOTIFY_MARK_FLAG_EXCL_UNLINK) + mask |= IN_EXCL_UNLINK; + if (fsn_mark->flags & FSNOTIFY_MARK_FLAG_IN_ONESHOT) + mask |= IN_ONESHOT; + + return mask; +} + +extern void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark, + struct fsnotify_group *group); +extern int inotify_handle_inode_event(struct fsnotify_mark *inode_mark, + u32 mask, struct inode *inode, + struct inode *dir, + const struct qstr *name, u32 cookie); + +extern const struct fsnotify_ops inotify_fsnotify_ops; +extern struct kmem_cache *inotify_inode_mark_cachep; + +#ifdef CONFIG_INOTIFY_USER +static inline void dec_inotify_instances(struct ucounts *ucounts) +{ + dec_ucount(ucounts, UCOUNT_INOTIFY_INSTANCES); +} + +static inline struct ucounts *inc_inotify_watches(struct ucounts *ucounts) +{ + return inc_ucount(ucounts->ns, ucounts->uid, UCOUNT_INOTIFY_WATCHES); +} + +static inline void dec_inotify_watches(struct ucounts *ucounts) +{ + dec_ucount(ucounts, UCOUNT_INOTIFY_WATCHES); +} +#endif -- cgit v1.3.1