From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
acme@x1:~/git/pahole$ tests/flexible_arrays.sh
Flexible arrays accounting: Ok
acme@x1:~/git/pahole$ VERBOSE=1 tests/flexible_arrays.sh
Flexible arrays accounting: end: mem_cgroup: 2 2
middle: mem_cgroup: 3 3
end: pglist_data: 2 2
middle: pglist_data: 0 0
end: zone: 3 3
middle: zone: 0 0
end: cgroup: 1 1
middle: cgroup: 0 0
end: cgroup_root: 1 1
middle: cgroup_root: 1 1
end: page_counter: 2 2
middle: page_counter: 0 0
end: cpu_hw_events: 1 1
middle: cpu_hw_events: 0 0
end: crypto_shash: 1 1
middle: crypto_shash: 0 0
end: crypto_aead: 1 1
middle: crypto_aead: 0 0
end: crypto_ahash: 1 1
middle: crypto_ahash: 0 0
end: crypto_skcipher: 1 1
middle: crypto_skcipher: 0 0
end: crypto_sync_skcipher: 0 0
middle: crypto_sync_skcipher: 1 1
<SNIP>
end: bpf_ctx_convert: 2 2
middle: bpf_ctx_convert: 0 0
Ok
acme@x1:~/git/pahole$
Cc: "Gustavo A. R. Silva" <gustavoars@xxxxxxxxxx>
Cc: Willy Tarreau <w@xxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tests/flexible_arrays.sh | 77 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 77 insertions(+)
create mode 100755 tests/flexible_arrays.sh
diff --git a/tests/flexible_arrays.sh b/tests/flexible_arrays.sh
new file mode 100755
index 0000000000000000..7c21253a7e08c9d3
--- /dev/null
+++ b/tests/flexible_arrays.sh
@@ -0,0 +1,77 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Match flexible array member info with the per struct final stats.
+#
+# Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> (C) 2024-
+
+vmlinux=${vmlinux:-$1}
+
+if [ -z "$vmlinux" ] ; then
+ vmlinux=$(pahole --running_kernel_vmlinux)
+fi
+
+if [ ! -f "$vmlinux" ] ; then
+ echo "$vmlinux file not available, please specify another"
+ exit 2
+fi
+
+pretty=$(mktemp /tmp/flexible_arrays.data.sh.XXXXXX.c)
+
+echo -n "Flexible arrays accounting: "
+
+for struct in $(pahole -F btf --sizes --with_embedded_flexible_array $vmlinux | cut -f1) ; do
+ pahole $struct > $pretty
+
+ # We need to check for just one tab before the comment as when expanding unnamed
+ # structs with members with flexible arrays inside another struct we would mess
+ # up the accounting, see 'pahole fanotify_fid_event' for instance, circa October 2024:
+ # $ pahole fanotify_fid_event
+ # struct fanotify_fid_event {
+ # struct fanotify_event fae; /* 0 48 */
+ # __kernel_fsid_t fsid; /* 48 8 */
+ # struct {
+ # struct fanotify_fh object_fh; /* 56 4 */
+ # /* XXX last struct has a flexible array */
+ # unsigned char _inline_fh_buf[12]; /* 60 12 */
+ # }; /* 56 16 */
+
+ # /* XXX last struct has embedded flexible array(s) */
+ # /* size: 72, cachelines: 2, members: 3 */
+ # /* flexible array members: middle: 1 */
+ # /* last cacheline: 8 bytes */
+ # }
+
+ nr_flexible_arrays=$(grep $'^\t/\* XXX last struct has a flexible array' $pretty | wc -l)
+ nr_embedded_flexible_arrays=$(grep $'^\t/\* XXX last struct.*embedded flexible array' $pretty | wc -l)
+ stat_nr_flexible_arrays=$(grep "flexible array members:.*end:" $pretty | sed -r 's/.*end: *([[:digit:]]+).*/\1/g')
+ [ -z "$stat_nr_flexible_arrays" ] && stat_nr_flexible_arrays=0
+ stat_nr_embedded_flexible_arrays=$(grep "flexible array members:.*middle:" $pretty | sed -r 's/.*middle: *([[:digit:]]+).*/\1/g')
+ [ -z "$stat_nr_embedded_flexible_arrays" ] && stat_nr_embedded_flexible_arrays=0
+ test -n "$VERBOSE" && echo "end: $struct: $nr_flexible_arrays $stat_nr_flexible_arrays"
+ test -n "$VERBOSE" && echo "middle: $struct: $nr_embedded_flexible_arrays $stat_nr_embedded_flexible_arrays"
+
+ if [ "$nr_embedded_flexible_arrays" != "$stat_nr_embedded_flexible_arrays" ] ; then
+ test -n "$VERBOSE" && printf "struct %s: The number of embedded flexible arrays (%s) doesn't match the number of members marked as such (%s)\n" \
+ "$struct" "$stat_nr_embedded_flexible_arrays" "$nr_embedded_flexible_arrays"
+ test -n "$VERBOSE" && pahole $struct
+ FAILED=1
+ fi
+
+ if [ "$nr_flexible_arrays" != "$stat_nr_flexible_arrays" ] ; then
+ test -n "$VERBOSE" && printf "struct %s: The number of flexible arrays (%s) doesn't match the number of members marked as such (%s)\n" \
+ "$struct" "$stat_nr_flexible_arrays" "$nr_flexible_arrays"
+ test -n "$VERBOSE" && pahole $struct
+ FAILED=1
+ fi
+
+ rm -f $pretty
+done
+
+if [ -n "$FAILED" ] ; then
+ echo "FAILED"
+ exit 1
+fi
+
+echo "Ok"
+exit 0
--
2.46.0
