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/gfs2/trans.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 fs/gfs2/trans.h (limited to 'fs/gfs2/trans.h') diff --git a/fs/gfs2/trans.h b/fs/gfs2/trans.h new file mode 100644 index 000000000..790c55f59 --- /dev/null +++ b/fs/gfs2/trans.h @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. + * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved. + */ + +#ifndef __TRANS_DOT_H__ +#define __TRANS_DOT_H__ + +#include +struct gfs2_sbd; +struct gfs2_rgrpd; +struct gfs2_glock; + +#define RES_DINODE 1 +#define RES_INDIRECT 1 +#define RES_JDATA 1 +#define RES_DATA 1 +#define RES_LEAF 1 +#define RES_RG_HDR 1 +#define RES_RG_BIT 2 +#define RES_EATTR 1 +#define RES_STATFS 1 +#define RES_QUOTA 2 + +/* reserve either the number of blocks to be allocated plus the rg header + * block, or all of the blocks in the rg, whichever is smaller */ +static inline unsigned int gfs2_rg_blocks(const struct gfs2_inode *ip, unsigned requested) +{ + struct gfs2_rgrpd *rgd = ip->i_res.rs_rgd; + + if (requested < rgd->rd_length) + return requested + 1; + return rgd->rd_length; +} + +int __gfs2_trans_begin(struct gfs2_trans *tr, struct gfs2_sbd *sdp, + unsigned int blocks, unsigned int revokes, + unsigned long ip); +int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks, + unsigned int revokes); + +void gfs2_trans_end(struct gfs2_sbd *sdp); +void gfs2_trans_add_data(struct gfs2_glock *gl, struct buffer_head *bh); +void gfs2_trans_add_databufs(struct gfs2_glock *gl, struct folio *folio, + size_t from, size_t len); +void gfs2_trans_add_meta(struct gfs2_glock *gl, struct buffer_head *bh); +void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd); +void gfs2_trans_remove_revoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len); +void gfs2_trans_free(struct gfs2_sbd *sdp, struct gfs2_trans *tr); + +#endif /* __TRANS_DOT_H__ */ -- cgit v1.3.1