18212f0648
The grub_disk_read() may trigger other disk reads, e.g. via loopbacks. This may lead to very deep recursion which can corrupt the heap. So, fix the issue by limiting reads depth. Reported-by: B Horn <b@horn.uk> Signed-off-by: B Horn <b@horn.uk> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>