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/xfs/scrub/trace.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 fs/xfs/scrub/trace.c (limited to 'fs/xfs/scrub/trace.c') diff --git a/fs/xfs/scrub/trace.c b/fs/xfs/scrub/trace.c new file mode 100644 index 000000000..e5efc6806 --- /dev/null +++ b/fs/xfs/scrub/trace.c @@ -0,0 +1,61 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2017-2023 Oracle. All Rights Reserved. + * Author: Darrick J. Wong + */ +#include "xfs_platform.h" +#include "xfs_fs.h" +#include "xfs_shared.h" +#include "xfs_format.h" +#include "xfs_log_format.h" +#include "xfs_trans_resv.h" +#include "xfs_mount.h" +#include "xfs_inode.h" +#include "xfs_btree.h" +#include "xfs_ag.h" +#include "xfs_rtbitmap.h" +#include "xfs_quota.h" +#include "xfs_quota_defs.h" +#include "xfs_da_format.h" +#include "xfs_dir2.h" +#include "xfs_rmap.h" +#include "xfs_parent.h" +#include "xfs_metafile.h" +#include "xfs_rtgroup.h" +#include "xfs_trans.h" +#include "scrub/scrub.h" +#include "scrub/xfile.h" +#include "scrub/xfarray.h" +#include "scrub/quota.h" +#include "scrub/iscan.h" +#include "scrub/orphanage.h" +#include "scrub/nlinks.h" +#include "scrub/fscounters.h" +#include "scrub/bitmap.h" +#include "scrub/ino_bitmap.h" +#include "scrub/xfblob.h" +#include "scrub/dirtree.h" + +/* Figure out which block the btree cursor was pointing to. */ +static inline xfs_fsblock_t +xchk_btree_cur_fsbno( + struct xfs_btree_cur *cur, + int level) +{ + if (level < cur->bc_nlevels && cur->bc_levels[level].bp) + return XFS_DADDR_TO_FSB(cur->bc_mp, + xfs_buf_daddr(cur->bc_levels[level].bp)); + + if (level == cur->bc_nlevels - 1 && + cur->bc_ops->type == XFS_BTREE_TYPE_INODE) + return XFS_INODE_TO_FSB(cur->bc_ino.ip); + + return NULLFSBLOCK; +} + +/* + * We include this last to have the helpers above available for the trace + * event implementations. + */ +#define CREATE_TRACE_POINTS +#include "scrub/trace.h" -- cgit v1.3.1