Why would enabling FIPS mode in the kernel break CIFS mounts?

Solution Verified - Updated -


  • CIFS mounts work well as long as FIPS mode is disabled.
  • Enabling FIPS mode and rebooting the server results in CIFS mounts failing. The kernel logs show this as:
CIFS VFS: could not allocate crypto hmacmd5

CIFS VFS: could not setup hash structures rc -2
CIFS VFS: cifs_mount failed w/return code = -2
  • The only difference between the success or failure of the CIFS mount is fips mode as enabled via fips=1 on the kernel command line in grub.conf.
  • Is FIPS mode supported with CIFS mounts?


  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7

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