Re: Build failure for kernel 4.9.94 for perf

[Greg KH <greg@kroah.com>]

On Sun, Apr 15, 2018 at 02:31:07PM +0200, Pavlos Parissis wrote:
> Hi,
> 
> Building 4.9.94 in the same way we have been building previous 4.9 releases yields the following error:
> 
> DEBUG: tests/code-reading.c: In function 'read_object_code':
> DEBUG: tests/code-reading.c:228:19: error: 'KMOD_DECOMP_LEN' undeclared (first use in this function)
> DEBUG:   char decomp_name[KMOD_DECOMP_LEN];
> DEBUG:                    ^
> DEBUG: tests/code-reading.c:228:19: note: each undeclared identifier is reported only once for each
> function it appears in
> DEBUG: tests/code-reading.c:291:3: warning: implicit declaration of function
> 'dso__decompress_kmodule_path' [-Wimplicit-function-declaration]
> DEBUG:    if (dso__decompress_kmodule_path(al.map->dso, objdump_name,
> DEBUG:    ^
> DEBUG: tests/code-reading.c:291:3: warning: nested extern declaration of
> 'dso__decompress_kmodule_path' [-Wnested-externs]
> DEBUG: tests/code-reading.c:228:7: warning: unused variable 'decomp_name' [-Wunused-variable]
> DEBUG:   char decomp_name[KMOD_DECOMP_LEN];
> DEBUG:        ^
> DEBUG:   CC       tests/topology.o
> DEBUG:   CC       tests/cpumap.o
> DEBUG:   CC       tests/stat.o
> DEBUG:   CC       tests/event_update.o
> DEBUG: mv: cannot stat 'tests/.code-reading.o.tmp': No such file or directory
> DEBUG: make[3]: *** [tests/code-reading.o] Error 1
> DEBUG: make[3]: *** Waiting for unfinished jobs....
> DEBUG: make[2]: *** [util] Error 2
> DEBUG: make[1]: *** [libperf-in.o] Error 2
> DEBUG: make[1]: *** Waiting for unfinished jobs....
> DEBUG:   LD       bench/perf-in.o
> DEBUG: make[2]: *** [tests] Error 2
> DEBUG: make[1]: *** [perf-in.o] Error 2
> 
> As far as I can see, KMOD_DECOMP_LEN was introduced by 7525a238be8f ("perf tests: Decompress kernel
> module before objdump"), but I have zero deep knowledge in this area so I may be very wrong here.

Yeah, looks like I need to just revert this patch, thanks, I'll do that
for the next release.

greg k-h