Messages in this thread | | | From | Sven Schnelle <> | Subject | Re: [PATCH v2 7/7] tools/testing/selftests/bpf: replace open-coded 16 with TASK_COMM_LEN | Date | Mon, 29 Nov 2021 11:13:31 +0100 |
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Hi,
Yafang Shao <laoar.shao@gmail.com> writes:
> As the sched:sched_switch tracepoint args are derived from the kernel, > we'd better make it same with the kernel. So the macro TASK_COMM_LEN is > converted to type enum, then all the BPF programs can get it through BTF. > > The BPF program which wants to use TASK_COMM_LEN should include the header > vmlinux.h. Regarding the test_stacktrace_map and test_tracepoint, as the > type defined in linux/bpf.h are also defined in vmlinux.h, so we don't > need to include linux/bpf.h again. > > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > Acked-by: Andrii Nakryiko <andrii@kernel.org> > Acked-by: David Hildenbrand <david@redhat.com> > Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> > Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> > Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> > Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Matthew Wilcox <willy@infradead.org> > Cc: David Hildenbrand <david@redhat.com> > Cc: Al Viro <viro@zeniv.linux.org.uk> > Cc: Kees Cook <keescook@chromium.org> > Cc: Petr Mladek <pmladek@suse.com> > --- > include/linux/sched.h | 9 +++++++-- > tools/testing/selftests/bpf/progs/test_stacktrace_map.c | 6 +++--- > tools/testing/selftests/bpf/progs/test_tracepoint.c | 6 +++--- > 3 files changed, 13 insertions(+), 8 deletions(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 78c351e35fec..cecd4806edc6 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -274,8 +274,13 @@ struct task_group; > > #define get_current_state() READ_ONCE(current->__state) > > -/* Task command name length: */ > -#define TASK_COMM_LEN 16 > +/* > + * Define the task command name length as enum, then it can be visible to > + * BPF programs. > + */ > +enum { > + TASK_COMM_LEN = 16, > +};
This breaks the trigger-field-variable-support.tc from the ftrace test suite at least on s390:
echo 'hist:keys=next_comm:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,sched.sched_waking.prio,next_comm) if next_comm=="ping"' linux/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-field-variable-support.tc: line 15: echo: write error: Invalid argument
I added a debugging line into check_synth_field():
[ 44.091037] field->size 16, hist_field->size 16, field->is_signed 1, hist_field->is_signed 0
Note the difference in the signed field.
Regards Sven
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