[ Upstream commit 06bd48b6cd97ef3889b68c8e09014d81dbc463f1 ] You can build a user-space test program for the raid6 library code, like this: $ cd lib/raid6/test $ make The command in $(shell ...) function is evaluated by /bin/sh by default. (or, you can specify the shell by passing SHELL=<shell> from command line) Currently '>&/dev/null' is used to sink both stdout and stderr. Because this code is bash-ism, it only works when /bin/sh is a symbolic link to bash (this is the case on RHEL etc.) This does not work on Ubuntu where /bin/sh is a symbolic link to dash. I see lots of /bin/sh: 1: Syntax error: Bad fd number and warning "your version of binutils lacks ... support" Replace it with portable '>/dev/null 2>&1'. Fixes: 4f8c55c5ad49 ("lib/raid6: build proper files on corresponding arch") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: H. Peter Anvin (Intel) <hpa@zytor.com> Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com> Acked-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Sasha Levin <sashal@kernel.org>