selftests/bpf: Add a test for objects stuck in free_by_rcu_ttracegrafted

Delete all elements of BPF_F_NO_PREALLOC hash map in one batch. The first
free_bulk() starts RCU tasks trace GP and the rest of the elements are
freed while it's in flight. Wait for call_rcu_ttrace_in_progress to clear
in bpf_mem_cache of every cpu and check that free_by_rcu_ttrace and
waiting_for_gp_ttrace lists are empty.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20260930095920.601738-4-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 54 insertions, 0 deletions

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)