[CRIU] zdtm test build failure on s390x (s390x_regs_check.c)

[Adrian Reber]

On Tue, Sep 05, 2017 at 07:47:26PM +0200, Michael Holzheu wrote:
> On Tue, 5 Sep 2017 17:56:08 +0200
> Adrian Reber <adrian at lisas.de> wrote:
> 
> > When running 'make zdtm' on s390x it fails on my RHEL kernel with:
> > 
> > make[3]: Leaving directory `/tmp/criu/test/zdtm/lib'
> >  CC        s390x_regs_check.o
> > s390x_regs_check.c: In function ‘util_hexdump_grp’:
> > s390x_regs_check.c:214:7: error: ‘ptr’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
> >    ptr += sprintf(ptr, "%02x", buf[i]);
> >        ^
> 
> Obviously the compiler does not understand the "if (first)" construct.
> 
> I assume the following will fix the problem:
> ---
> [CRIU][PATCH] zdtm/s390x_regs_check: Fix compiler warning
> 
> When running 'make zdtm' on s390x it fails on RHEL7 with:
> 
>  make[3]: Leaving directory `/tmp/criu/test/zdtm/lib'
>   CC        s390x_regs_check.o
>  s390x_regs_check.c: In function "util_hexdump_grp":
>  s390x_regs_check.c:214:7: error: "ptr" may be used uninitialized
>  in this function [-Werror=maybe-uninitialized]
>     ptr += sprintf(ptr, "%02x", buf[i]);
> 
> Fix this and assign ptr from the beginning to help gcc.
> 
> Signed-off-by: Michael Holzheu <holzheu at linux.vnet.ibm.com>
> ---
>  test/zdtm/static/s390x_regs_check.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/test/zdtm/static/s390x_regs_check.c b/test/zdtm/static/s390x_regs_check.c
> index a92679a..1a7e841 100644
> --- a/test/zdtm/static/s390x_regs_check.c
> +++ b/test/zdtm/static/s390x_regs_check.c
> @@ -198,8 +198,8 @@ struct reg_set *reg_set_vec[] = {
>  void util_hexdump_grp(const char *tag, const void *data, int grp,
>  		      int count, int indent)
>  {
> +	char str[1024], *ptr = str;
>  	const char *buf = data;
> -	char str[1024], *ptr;
>  	int i, first = 1;
>  
>  	for (i = 0; i < count; i++) {
> -- 
> 2.7.4

Thanks the patch works. Now it compiles without errors. But...

The test seems to hang. criu never starts in zdtm.py to do the actual
dump. In the output file I see:

11:48:08.040: 45159: ------------- START 1 PROCESS + 2 THREADS ---------------
11:48:08.080: 45159: STARTED: pid = 45160
11:48:08.149: 45159: STARTED: pid = 45162
11:48:08.149: 45159: STARTED: pid = 45161
11:48:08.149: 45159: ---------------------- SET REGISTERS --------------------
11:48:08.149: 45159: SET: pid = 45160
11:48:08.174: 45159:  REGSET:      PRFPREG -> DONE
11:48:08.174: 45159:  REGSET:     VXRS_LOW -> not supported by machine
11:48:08.174: 45159:  REGSET:    VXRS_HIGH -> not supported by machine
11:48:08.174: 45159: SET: pid = 45162

One of the three process uses 100% CPU and that is how the process tree looks like:

45166 pts/0    S+     0:00  |       \_ python2 ./zdtm.py run -f h,ns -t zdtm/static/s390x_regs_check
45176 pts/0    S+     0:00  |           \_ ./zdtm_ct zdtm.py
45179 pts/0    S+     0:00  |           |   \_ python2 zdtm.py
45182 pts/0    S+     0:00  |           |       \_ python2 zdtm.py
45199 pts/0    S+     0:00  |           |           \_ make --no-print-directory -C zdtm/static s390x_regs_check.pid
45214 pts/0    S+     0:00  |           |               \_ ./s390x_regs_check --pidfile=s390x_regs_check.pid --outfile=s390x_regs_check.out
45215 ?        Ss     0:00  |           |                   \_ ./s390x_regs_check --pidfile=s390x_regs_check.pid --outfile=s390x_regs_check.out
45216 ?        Rl     0:16  |           |                       \_ ./s390x_regs_check --pidfile=s390x_regs_check.pid --outfile=s390x_regs_check.out
45219 pts/0    R+     0:00  |           \_ ps axf

		Adrian