Linux 5.10 contains this patch:
commit 2a36ab717e8fe678d98f81c14a0b124712719840
Author: Peter Oskolkov <posk@xxxxxxxxxx>
Date: Wed Sep 23 16:36:16 2020 -0700
rseq/membarrier: Add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
This adds an argument to an existing syscall. Before the patch,
membarrier had 2 parameters; now it has 3. Is this really okay? At
least the patch is careful and ignores the third parameter unless a
previously unused flag bit is set.
--Andy
