See also https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=987008

When handling a regular LVM volume, Grub can fail with the message:
error: disk `lvmid/******-****-****-****-****-****-
****/******-****-****-****-****-****-******' not found.

If the condition which triggers this exists, grub-probe will report the error mentioned above. Similarly, the grub boot code will fail to detect LVM volumes, resulting in a failure to boot off of LVM disks/partitions. The condition can be created on any LVM VG by an LVM configuration change, so any system with /boot on LVM can become unbootable at 'any' time (after any LVM configuration change).

==== Cause ===
The problem is caused by an incorrect computation of mda_end in lvm.c, when the metadata area wraps around.
Patch included below.

How to reproduce

Run the (first) attached script (as root!). On my system, it reliably fails at lv81. If not, the second script can be run until the error occurs. It requires a parameter indicating the number of iterations.
WARNING: Don't run the scripts if you don't understand what they do.
WARNING 2: The name of the loop device may have to be changed before running the script!

Patch

I hereby release this patch to the public domain, to (hopefully) avoid any copyright assignment problems.
---------------------------------------------------
Index: grub2-2.02+dfsg1/grub-core/disk/lvm.c
===================================================================
--- grub2-2.02+dfsg1.orig/grub-core/disk/lvm.c
+++ grub2-2.02+dfsg1/grub-core/disk/lvm.c
@@ -253,7 +253,7 @@ error_parsing_metadata:

   p = q = (char *)ptr;

-  if (grub_add ((grub_size_t)metadatabuf, (grub_size_t)mda_size, &ptr))
+  if (grub_add (ptr, (grub_size_t)grub_le_to_cpu64 (rlocn->size), &ptr))
     goto error_parsing_metadata;

   mda_end = (char *)ptr;
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