NACK: [PATCH trusty] UBUNTU: Makefile.build: do not forget to run fixdep on .S files

[Stefan Bader]

On 05.05.20 08:35, Jason A. Donenfeld wrote:
> When Andy converted the .S rule from the basic if_changed_dep to
> if_changed_rule, he forgot to add in the requisite call to fixdep inside
> the rule. The consequence of this is that when modpost is called,
> symbol extraction will cease following the first missing .o.cmd file,
> the absence of which is caused by fixdep not running. When compiling
> WireGuard, this manifests itself with this sort of WARNING message, and
> under the hood the consequences are worse than a mere warning, since
> processing of subsequent files stops:
> 
>   Building modules, stage 2.
>   MODPOST 1 modules
> WARNING: could not find /root/wireguard-linux-compat/src/crypto/zinc/chacha20/.chacha20-x86_64.o.cmd for /root/wireguard-linux-compat/src/crypto/zinc/chacha20/chacha20-x86_64.o
> 
> Further, as a consequence of there being no .o.cmd file, the build
> system is unable to determine whether or not the files changed,
> resulting in a rebuild of all .S->.o files on subsequent calls to make:
> 
> root at ubuntu:~/wireguard-linux-compat/src# make
>   AS [M]  /root/wireguard-linux-compat/src/crypto/zinc/chacha20/chacha20-x86_64.o
>   AS [M]  /root/wireguard-linux-compat/src/crypto/zinc/poly1305/poly1305-x86_64.o
>   AS [M]  /root/wireguard-linux-compat/src/crypto/zinc/blake2s/blake2s-x86_64.o
>   ...
> 
> The fix to this is simple: simply add in the call to fixdep in the
> as_o_S rule definition.
> 
> Fixes: 057bd70e ("UBUNTU: [Packaging] retpoline -- add safe usage hint support")
> Signed-off-by: Jason A. Donenfeld <Jason at zx2c4.com>
> ---

Trusty is in ESM (extended security maintenance). This means only high/critical
security issues get fixed.

-Stefan

> I've been spending some time making sure that WireGuard will be flawless
> when it's added to 14.04 as a pre-built, and this is the only remaining
> issue that cannot (easily) be fixed from the compat layer.
> 
>  scripts/Makefile.build | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index 645677c3..bb272a14 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -312,7 +312,11 @@ endef
>  
>  define rule_as_o_S
>  	$(call echo-cmd,as_o_S) $(cmd_as_o_S);				  \
> -	$(call echo-cmd,ubuntu-retpoline) $(cmd_ubuntu_retpoline)
> +	$(call echo-cmd,ubuntu-retpoline) $(cmd_ubuntu_retpoline)         \
> +	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,as_o_S)' >    \
> +	                                              $(dot-target).tmp;  \
> +	rm -f $(depfile);						  \
> +	mv -f $(dot-target).tmp $(dot-target).cmd
>  endef
>  
>  # Built-in and composite module parts
> 


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