Re: [PATCH bpf-next v4 0/8] Add Open-coded task, css_task and css iters

[Chuyi Zhou]

Hello,

在 2023/10/10 16:01, Daniel Borkmann 写道:
> On 10/7/23 2:45 PM, Chuyi Zhou wrote:
> > Hi,
> >
> > This is version 4 of task, css_task and css iters support.
> > Thanks for your review!
> >
> > --- Changelog ---
> >
> > v3 -> 
> > v4:https://lore.kernel.org/all/20230925105552.817513-1-zhouchuyi@xxxxxxxxxxxxx/
> >
> > * Address all the comments from Andrii in patch-3 ~ patch-6
> > * Collect Tejun's ack
> > * Add a extra patch to rename bpf_iter_task.c to bpf_iter_tasks.c
> > * Seperate three BPF program files for selftests (iters_task.c 
> > iters_css_task.c iters_css.c)
>
> This fails to build BPF selftests:

Yes, thanks for the remind!

I didn't notice this error since it may only occurs when using llvm-16 
to compile the selftest, and when we using gcc, it works OK.
(https://github.com/kernel-patches/bpf/actions/runs/6462875618/job/17545170863)

I can reproduce this error in my environment. Before sending next 
version, I would use LLVM-16 to double check.

Thanks.


> [...]
>   /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:166:6: error: variable 'skel' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
>            if (!ASSERT_OK(err, "setup_cgroup_environment"))
>                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:190:26: 
> note: uninitialized use occurs here
>            iters_css_task__destroy(skel);
>                                    ^~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:166:2: 
> note: remove the 'if' if its condition is always false
>            if (!ASSERT_OK(err, "setup_cgroup_environment"))
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:162:6: 
> error: variable 'skel' is used uninitialized whenever 'if' condition is 
> true [-Werror,-Wsometimes-uninitialized]
>            if (!ASSERT_GE(cg_fd, 0, "cg_create"))
>      TEST-OBJ [test_progs] xdp.test.o
>                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:190:26: 
> note: uninitialized use occurs here
>            iters_css_task__destroy(skel);
>                                    ^~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:162:2: 
> note: remove the 'if' if its condition is always false
>            if (!ASSERT_GE(cg_fd, 0, "cg_create"))
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:159:6: 
> error: variable 'skel' is used uninitialized whenever 'if' condition is 
> true [-Werror,-Wsometimes-uninitialized]
>            if (!ASSERT_OK(err, "setup_cgroup_environment"))
>                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:190:26: 
> note: uninitialized use occurs here
>            iters_css_task__destroy(skel);
>                                    ^~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:159:2: 
> note: remove the 'if' if its condition is always false
>            if (!ASSERT_OK(err, "setup_cgroup_environment"))
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:154:29: 
> note: initialize the variable 'skel' to silence this warning
>            struct iters_css_task *skel;
>                                       ^
>                                        = NULL
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:213:7: 
> error: variable 'skel' is used uninitialized whenever 'if' condition is 
> true [-Werror,-Wsometimes-uninitialized]
>                    if (!ASSERT_GE(cgs[i].fd, 0, "cg_create"))
>                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:244:21: 
> note: uninitialized use occurs here
>            iters_css__destroy(skel);
>                               ^~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:213:3: 
> note: remove the 'if' if its condition is always false
>                    if (!ASSERT_GE(cgs[i].fd, 0, "cg_create"))
>                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:209:6: 
> error: variable 'skel' is used uninitialized whenever 'if' condition is 
> true [-Werror,-Wsometimes-uninitialized]
>            if (!ASSERT_OK(err, "setup_cgroup_environment"))
>                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:244:21: 
> note: uninitialized use occurs here
>            iters_css__destroy(skel);
>                               ^~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:209:2: 
> note: remove the 'if' if its condition is always false
>            if (!ASSERT_OK(err, "setup_cgroup_environment"))
>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/iters.c:195:24: 
> note: initialize the variable 'skel' to silence this warning
>            struct iters_css *skel;
>                                  ^
>                                   = NULL
>    5 errors generated.
>    make: *** [Makefile:605: 
> /tmp/work/bpf/bpf/tools/testing/selftests/bpf/iters.test.o] Error 1
>    make: *** Waiting for unfinished jobs....
>    make: Leaving directory '/tmp/work/bpf/bpf/tools/testing/selftests/bpf'
>    Error: Process completed with exit code 2.