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 --- scripts/coccinelle/misc/doubleinit.cocci | 54 ++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 scripts/coccinelle/misc/doubleinit.cocci (limited to 'scripts/coccinelle/misc/doubleinit.cocci') diff --git a/scripts/coccinelle/misc/doubleinit.cocci b/scripts/coccinelle/misc/doubleinit.cocci new file mode 100644 index 000000000..7dbfde3f4 --- /dev/null +++ b/scripts/coccinelle/misc/doubleinit.cocci @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0-only +/// Find duplicate field initializations. This has a high rate of false +/// positives due to #ifdefs, which Coccinelle is not aware of in a structure +/// initialization. +/// +// Confidence: Low +// Copyright: (C) 2010-2012 Nicolas Palix. +// Copyright: (C) 2010-2012 Julia Lawall, INRIA/LIP6. +// Copyright: (C) 2010-2012 Gilles Muller, INRIA/LiP6. +// URL: https://coccinelle.gitlabpages.inria.fr/website +// Comments: requires at least Coccinelle 0.2.4, lex or parse error otherwise +// Options: --no-includes --include-headers + +virtual org +virtual report + +@r@ +identifier I, s, fld; +position p0,p; +expression E; +@@ + +struct I s =@p0 { ..., .fld@p = E, ...}; + +@s@ +identifier I, s, r.fld; +position r.p0,p; +expression E; +@@ + +struct I s =@p0 { ..., .fld@p = E, ...}; + +@script:python depends on org@ +p0 << r.p0; +fld << r.fld; +ps << s.p; +pr << r.p; +@@ + +if int(ps[0].line) < int(pr[0].line) or (int(ps[0].line) == int(pr[0].line) and int(ps[0].column) < int(pr[0].column)): + cocci.print_main(fld,p0) + cocci.print_secs("s",ps) + cocci.print_secs("r",pr) + +@script:python depends on report@ +p0 << r.p0; +fld << r.fld; +ps << s.p; +pr << r.p; +@@ + +if int(ps[0].line) < int(pr[0].line) or (int(ps[0].line) == int(pr[0].line) and int(ps[0].column) < int(pr[0].column)): + msg = "%s: first occurrence line %s, second occurrence line %s" % (fld,ps[0].line,pr[0].line) + coccilib.report.print_report(p0[0],msg) -- cgit v1.3.1