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/discard.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 fs/btrfs/discard.h (limited to 'fs/btrfs/discard.h') diff --git a/fs/btrfs/discard.h b/fs/btrfs/discard.h new file mode 100644 index 000000000..2c5e85394 --- /dev/null +++ b/fs/btrfs/discard.h @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef BTRFS_DISCARD_H +#define BTRFS_DISCARD_H + +#include +#include + +struct btrfs_fs_info; +struct btrfs_discard_ctl; +struct btrfs_block_group; + +/* Discard size limits */ +#define BTRFS_ASYNC_DISCARD_DEFAULT_MAX_SIZE (SZ_64M) +#define BTRFS_ASYNC_DISCARD_MAX_FILTER (SZ_1M) +#define BTRFS_ASYNC_DISCARD_MIN_FILTER (SZ_32K) + +/* List operations */ +void btrfs_discard_check_filter(struct btrfs_block_group *block_group, u64 bytes); + +/* Work operations */ +void btrfs_discard_cancel_work(struct btrfs_discard_ctl *discard_ctl, + struct btrfs_block_group *block_group); +void btrfs_discard_queue_work(struct btrfs_discard_ctl *discard_ctl, + struct btrfs_block_group *block_group); +void btrfs_discard_schedule_work(struct btrfs_discard_ctl *discard_ctl, + bool override); + +/* Update operations */ +void btrfs_discard_calc_delay(struct btrfs_discard_ctl *discard_ctl); +void btrfs_discard_update_discardable(struct btrfs_block_group *block_group); + +/* Setup/cleanup operations */ +void btrfs_discard_punt_unused_bgs_list(struct btrfs_fs_info *fs_info); +void btrfs_discard_resume(struct btrfs_fs_info *fs_info); +void btrfs_discard_stop(struct btrfs_fs_info *fs_info); +void btrfs_discard_init(struct btrfs_fs_info *fs_info); +void btrfs_discard_cleanup(struct btrfs_fs_info *fs_info); + +#endif -- cgit v1.3.1