From a29b17f1cb53ee24075f09674d760a40eec6294f Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Wed, 14 Jan 2026 08:53:29 +0800
Subject: [PATCH] readelf: Display and return true for empty note
 section/segment

Change readelf to display and return true for empty note section and
segment.  Add a linker test to verify that empty note section is
discarded.

binutils/

	PR ld/33780
	* readelf.c (process_notes_at): Display and return true for empty
	note section and segment.

gas/

	PR ld/33780
	* testsuite/gas/elf/elf.exp: Run empty-note.
	* testsuite/gas/elf/empty-note.d: New file.
	* testsuite/gas/elf/empty-note.s: Likewise.

ld/

	PR ld/33780
	* testsuite/ld-elf/empty-note.d: New file.
	* testsuite/ld-elf/empty-note.s: Likewise.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
---
 binutils/readelf.c                 | 13 +++++++++++--
 gas/testsuite/gas/elf/elf.exp      |  5 +++++
 gas/testsuite/gas/elf/empty-note.d | 14 ++++++++++++++
 gas/testsuite/gas/elf/empty-note.s | 16 ++++++++++++++++
 ld/testsuite/ld-elf/empty-note.d   | 11 +++++++++++
 ld/testsuite/ld-elf/empty-note.s   |  2 ++
 6 files changed, 59 insertions(+), 2 deletions(-)
 create mode 100644 gas/testsuite/gas/elf/empty-note.d
 create mode 100644 gas/testsuite/gas/elf/empty-note.s
 create mode 100644 ld/testsuite/ld-elf/empty-note.d
 create mode 100644 ld/testsuite/ld-elf/empty-note.s

diff --git a/binutils/readelf.c b/binutils/readelf.c
index 5b7fc0dc1de..a889cd62607 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -23885,8 +23885,17 @@ process_notes_at (Filedata *           filedata,
   char *end;
   bool res = true;
 
-  if (length <= 0)
-    return false;
+  if (length == 0)
+    {
+      if (section)
+	printf (_("Empty note section: %s\n"),
+		printable_section_name (filedata, section));
+      else
+	printf (_("Empty note segment at file offset 0x%08" PRIx64
+		  " with length 0x%08" PRIx64 ":\n"),
+		offset, length);
+      return true;
+    }
 
   if (section)
     {
diff --git a/gas/testsuite/gas/elf/elf.exp b/gas/testsuite/gas/elf/elf.exp
index b4b4272ab9f..457871e1afa 100644
--- a/gas/testsuite/gas/elf/elf.exp
+++ b/gas/testsuite/gas/elf/elf.exp
@@ -294,7 +294,9 @@ if { [is_elf_format] } then {
     run_dump_test "sh-link-abs-2"
     run_dump_test "sh-link-common-1"
     run_dump_test "sh-link-common-2"
+    set saved_ASFLAGS "$ASFLAGS"
     if [is_elf64 tmpdir/section30.o] {
+	set ASFLAGS "$ASFLAGS --defsym ALIGN=3"
 	run_dump_test "sh-link-abs-3-64"
 	run_dump_test "sh-link-abs-4-64"
 	run_dump_test "sh-link-common-3-64"
@@ -304,11 +306,14 @@ if { [is_elf_format] } then {
 	run_dump_test "sh-link-large-common-3"
 	run_dump_test "sh-link-large-common-4"
     } else {
+	set ASFLAGS "$ASFLAGS --defsym ALIGN=2"
 	run_dump_test "sh-link-abs-3-32"
 	run_dump_test "sh-link-abs-4-32"
 	run_dump_test "sh-link-common-3-32"
 	run_dump_test "sh-link-common-4-32"
     }
+    run_dump_test "empty-note"
+    set ASFLAGS "$saved_ASFLAGS"
     run_dump_test "sh-link-zero"
     run_dump_test "string"
     run_dump_test "size"
diff --git a/gas/testsuite/gas/elf/empty-note.d b/gas/testsuite/gas/elf/empty-note.d
new file mode 100644
index 00000000000..00141423ff0
--- /dev/null
+++ b/gas/testsuite/gas/elf/empty-note.d
@@ -0,0 +1,14 @@
+#readelf: -n
+#notarget: am33_2.0-*-* hppa*-*-hpux* mn10300-*-*
+# Assembly source file for the HPPA assembler is renamed and modifed by
+# sed.  mn10300 has relocations in .note.gnu.property section which
+# elf_parse_notes doesn't support.
+
+#...
+Empty note section: .note.foo
+
+Displaying notes found in: .note.gnu.property
+[ 	]+Owner[ 	]+Data size[ 	]+Description
+  GNU                  0x[0-9a-f]+	NT_GNU_PROPERTY_TYPE_0
+      Properties: UINT32_OR \(0xb000ffff\): 0x3
+#pass
diff --git a/gas/testsuite/gas/elf/empty-note.s b/gas/testsuite/gas/elf/empty-note.s
new file mode 100644
index 00000000000..44880391b4c
--- /dev/null
+++ b/gas/testsuite/gas/elf/empty-note.s
@@ -0,0 +1,16 @@
+	.section .note.foo,"","note"
+	.section ".note.gnu.property", "a"
+	.p2align ALIGN
+	.long 1f - 0f		/* name length */
+	.long 5f - 2f		/* data length */
+	.long 5			/* note type */
+0:	.asciz "GNU"		/* vendor name */
+1:
+	.p2align ALIGN
+2:	.long 0xb000ffff	/* pr_type.  */
+	.long 4f - 3f		/* pr_datasz.  */
+3:
+	.long 0x3
+4:
+	.p2align ALIGN
+5:
diff --git a/ld/testsuite/ld-elf/empty-note.d b/ld/testsuite/ld-elf/empty-note.d
new file mode 100644
index 00000000000..9cd9545a78b
--- /dev/null
+++ b/ld/testsuite/ld-elf/empty-note.d
@@ -0,0 +1,11 @@
+#as: --generate-missing-build-notes=no
+#ld: -shared
+#readelf: -SlW
+#xfail: ![check_shared_lib_support]
+
+#failif
+#...
+  \[[ 0-9]+\] \.note.foo[ \t]+NOTE[ \t]+.*
+#...
+  NOTE +.*
+#...
diff --git a/ld/testsuite/ld-elf/empty-note.s b/ld/testsuite/ld-elf/empty-note.s
new file mode 100644
index 00000000000..7b0e88c2707
--- /dev/null
+++ b/ld/testsuite/ld-elf/empty-note.s
@@ -0,0 +1,2 @@
+	.section .note.foo,"a","note"
+	.section .note.GNU-stack,"","progbits"
-- 
2.52.0