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/btrfs/super.h | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 fs/btrfs/super.h (limited to 'fs/btrfs/super.h') diff --git a/fs/btrfs/super.h b/fs/btrfs/super.h new file mode 100644 index 000000000..f85f8a8a7 --- /dev/null +++ b/fs/btrfs/super.h @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef BTRFS_SUPER_H +#define BTRFS_SUPER_H + +#include +#include +#include "fs.h" + +struct super_block; +struct btrfs_fs_info; + +bool btrfs_check_options(const struct btrfs_fs_info *info, + unsigned long long *mount_opt, + unsigned long flags); +int btrfs_sync_fs(struct super_block *sb, int wait); +char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info, + u64 subvol_objectid); +void btrfs_set_free_space_cache_settings(struct btrfs_fs_info *fs_info); + +static inline struct btrfs_fs_info *btrfs_sb(const struct super_block *sb) +{ + return sb->s_fs_info; +} + +static inline void btrfs_set_sb_rdonly(struct super_block *sb) +{ + sb->s_flags |= SB_RDONLY; + set_bit(BTRFS_FS_STATE_RO, &btrfs_sb(sb)->fs_state); +} + +static inline void btrfs_clear_sb_rdonly(struct super_block *sb) +{ + sb->s_flags &= ~SB_RDONLY; + clear_bit(BTRFS_FS_STATE_RO, &btrfs_sb(sb)->fs_state); +} + +#endif -- cgit v1.3.1