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, 34 insertions, 0 deletions

diff --git a/scripts/stackusage b/scripts/stackusage
new file mode 100755
index 000000000..56ef1ab67
--- /dev/null
+++ b/scripts/stackusage
@@ -0,0 +1,34 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+outfile=""
+now=`date +%s`
+
+while [ $# -gt 0 ]
+do
+    case "$1" in
+        -o)
+	    outfile="$2"
+	    shift 2;;
+	-h)
+	    echo "usage: $0 [-o outfile] <make options/args>"
+	    exit 0;;
+	*)  break;;
+    esac
+done
+
+if [ -z "$outfile" ]
+then
+    outfile=`mktemp --tmpdir stackusage.$$.XXXX`
+fi
+
+KCFLAGS="${KCFLAGS} -fstack-usage" make "$@"
+
+# Prepend directory name to file names, remove column information,
+# make file:line/function/size/type properly tab-separated.
+find . -name '*.su' -newermt "@${now}" -print |                     \
+    xargs perl -MFile::Basename -pe                                 \
+        '$d = dirname($ARGV); s#([^:]+:[0-9]+):[0-9]+:#$d/$1\t#;' | \
+    sort -k3,3nr > "${outfile}"
+
+echo "$0: output written to ${outfile}"