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/lops.h | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 fs/gfs2/lops.h (limited to 'fs/gfs2/lops.h') diff --git a/fs/gfs2/lops.h b/fs/gfs2/lops.h new file mode 100644 index 000000000..772557b63 --- /dev/null +++ b/fs/gfs2/lops.h @@ -0,0 +1,91 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. + * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. + */ + +#ifndef __LOPS_DOT_H__ +#define __LOPS_DOT_H__ + +#include +#include "incore.h" + +extern const struct gfs2_log_operations *gfs2_log_ops[]; + +void gfs2_log_incr_head(struct gfs2_sbd *sdp); +u64 gfs2_log_bmap(struct gfs2_jdesc *jd, unsigned int lbn); +void gfs2_log_write(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd, + struct page *page, unsigned size, unsigned offset, + u64 blkno, blk_opf_t opf); +void gfs2_log_submit_write(struct bio **biop); +void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh); +int gfs2_find_jhead(struct gfs2_jdesc *jd, + struct gfs2_log_header_host *head); +void gfs2_drain_revokes(struct gfs2_sbd *sdp); + +static inline unsigned int buf_limit(struct gfs2_sbd *sdp) +{ + return sdp->sd_ldptrs; +} + +static inline unsigned int databuf_limit(struct gfs2_sbd *sdp) +{ + return sdp->sd_ldptrs / 2; +} + +static inline void lops_before_commit(struct gfs2_sbd *sdp, + struct gfs2_trans *tr) +{ + int x; + for (x = 0; gfs2_log_ops[x]; x++) + if (gfs2_log_ops[x]->lo_before_commit) + gfs2_log_ops[x]->lo_before_commit(sdp, tr); +} + +static inline void lops_after_commit(struct gfs2_sbd *sdp, + struct gfs2_trans *tr) +{ + int x; + for (x = 0; gfs2_log_ops[x]; x++) + if (gfs2_log_ops[x]->lo_after_commit) + gfs2_log_ops[x]->lo_after_commit(sdp, tr); +} + +static inline void lops_before_scan(struct gfs2_jdesc *jd, + struct gfs2_log_header_host *head, + unsigned int pass) +{ + int x; + for (x = 0; gfs2_log_ops[x]; x++) + if (gfs2_log_ops[x]->lo_before_scan) + gfs2_log_ops[x]->lo_before_scan(jd, head, pass); +} + +static inline int lops_scan_elements(struct gfs2_jdesc *jd, u32 start, + struct gfs2_log_descriptor *ld, + __be64 *ptr, + unsigned int pass) +{ + int x, error; + for (x = 0; gfs2_log_ops[x]; x++) + if (gfs2_log_ops[x]->lo_scan_elements) { + error = gfs2_log_ops[x]->lo_scan_elements(jd, start, + ld, ptr, pass); + if (error) + return error; + } + + return 0; +} + +static inline void lops_after_scan(struct gfs2_jdesc *jd, int error, + unsigned int pass) +{ + int x; + for (x = 0; gfs2_log_ops[x]; x++) + if (gfs2_log_ops[x]->lo_before_scan) + gfs2_log_ops[x]->lo_after_scan(jd, error, pass); +} + +#endif /* __LOPS_DOT_H__ */ + -- cgit v1.3.1