LVM commands hang with: "flock failed: Interrupted system call"

Issue

• LVM commands hang, and can continue with ctrl-c. The ctrl-c interrupts the flock call and allows the command to continue. Using strace, it is found the failure is at _do_flock against the VG lock file; failure message after interrupt: "flock failed: Interrupted system call" and "Can't get lock for vg_name".

#misc/lvm-flock.c:71       Unlocking /var/lock/lvm/V_d6d7afa9-5356-4c12-9659-5817f6767c5e
#misc/lvm-flock.c:48         _undo_flock /var/lock/lvm/V_d6d7afa9-5356-4c12-9659-5817f6767c5e
#device/dev-io.c:587         Closed /dev/mapper/3514f0c51484000e3
#metadata/vg.c:84         Freeing VG d6d7afa9-5356-4c12-9659-5817f6767c5e at 0x7fb560c1da30.
#metadata/vg.c:84         Freeing VG d6d7afa9-5356-4c12-9659-5817f6767c5e at 0x7fb560c19a20.
#misc/lvm-flock.c:200       Locking /var/lock/lvm/V_dc25e385-332e-4feb-8ea2-78a7036ac8d1 RB
#libdm-common.c:903         Preparing SELinux context for /var/lock/lvm/V_dc25e385-332e-4feb-8ea2-78a7036ac8d1 to system_u:object_r:lvm_lock_t:s0.
#misc/lvm-flock.c:101         _do_flock /var/lock/lvm/V_dc25e385-332e-4feb-8ea2-78a7036ac8d1:aux WB
<ctrl-c>
#misc/lvm-signal.c:38   Interrupted...
#misc/lvm-flock.c:121   Giving up waiting for lock.
#misc/lvm-flock.c:126   /var/lock/lvm/V_dc25e385-332e-4feb-8ea2-78a7036ac8d1:aux: flock failed: Interrupted system call
#libdm-common.c:906         Resetting SELinux context to default value.
#misc/lvm-flock.c:214         <backtrace>
#locking/file_locking.c:89         <backtrace>
#locking/locking.c:283         <backtrace>
#locking/locking.c:355         <backtrace>
#metadata/metadata.c:4607   Can't get lock for dc25e385-332e-4feb-8ea2-78a7036ac8d1
#metadata/vg.c:69         Allocated VG (null) at 0x7fb560c19a20.
#toollib.c:223   Cannot process volume group dc25e385-332e-4feb-8ea2-78a7036ac8d1

• Please note in this article the volume group names are UUIDs; they are created by VDSM. That will not be the case for all systems that see the issue. They may be user friendly names like VG1.