common: handle old versions of modprobe which don't support --help

There exists versions of modprobe out there which are so old that
modprobe --help isn't a thing.  They're certainly not going to support
modprobe --remove-patiently, so test to make sure modprobe --help
works to avoid causing all tests to fail due to the error message
to stderr showing up in $seq.out.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Fixes: 405c21d40aa1 ("common/module: add patient module rmmod support")
Reported-by: Leah Rumancik <leah.rumancik@gmail.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

diff --git a/common/config b/common/config
index 2b357746476bffd3066af02388c0c56c042c3038..0566ab4a963e038971ac98da11f42c1e86dff04f 100644 (file)
--- a/common/config
+++ b/common/config
@@ -256,7 +256,7 @@ export UDEV_SETTLE_PROG
 # Set MODPROBE_PATIENT_RM_TIMEOUT_SECONDS to "forever" if you want the patient
 # modprobe removal to run forever trying to remove a module.
 MODPROBE_REMOVE_PATIENT=""
-modprobe --help | grep -q -1 "remove-patiently"
+modprobe --help >& /dev/null && modprobe --help | grep -q -1 "remove-patiently"
 if [[ $? -ne 0 ]]; then
        if [[ -z "$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS" ]]; then
                # We will open code our own implementation of patient module