Failures in qemu-iotests due to bash-5.3 and/or readline-8.3

Host environment

• Operating system: Arch Linux
• OS/kernel version: Linux arch 6.15.8-arch1-1 #1 SMP PREEMPT_DYNAMIC Thu, 24 Jul 2025 18:18:11 +0000 x86_64 GNU/Linux
• Architecture: x86_64
• QEMU flavor: qemu-system-x86_64
• QEMU version: 10.1.0-rc0 & 10.0.3
• QEMU command line: N/A

Description of problem

Running make check on a system with latest bash-5.3/readline-8.3 installed results in 3 test suite failures:

Summary of Failures:

304/487 qemu:block / io-qcow2-039                                           ERROR            0.50s   exit status 1
348/487 qemu:block / io-qcow2-137                                           ERROR            0.48s   exit status 1
368/487 qemu:block / io-qcow2-061                                           ERROR            2.39s   exit status 1

The failures all look similar to this, so it appears to be a simple case of differing whitespace:

stderr:
--- /build/qemu/src/qemu-10.1.0-rc0/tests/qemu-iotests/039.out
+++ /build/qemu/src/build/scratch/qcow2-file-039/039.out.bad
@@ -11,7 +11,7 @@
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728
 wrote 512/512 bytes at offset 0
 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-./common.rc: Killed                  ( VALGRIND_QEMU="${VALGRIND_QEMU_IO}" _qemu_proc_exec "${VALGRIND_LOGFILE}" "$QEMU_IO_PROG" $QEMU_IO_ARGS "$@" )
+./common.rc: Killed                     ( VALGRIND_QEMU="${VALGRIND_QEMU_IO}" _qemu_proc_exec "${VALGRIND_LOGFILE}" "$QEMU_IO_PROG" $QEMU_IO_ARGS "$@" )
 incompatible_features     [0]
 ERROR cluster 5 refcount=0 reference=1
 ERROR OFLAG_COPIED data cluster: l2_entry=8000000000050000 refcount=0

Steps to reproduce

1. upgrade to latest bash-5.3 and readline-8.3
2. build QEMU
3. run make check

Additional information

Downgrading back to bash-5.2 and readline-8.2 results in the test suite passing again. Any thoughts? Thanks.