On Sat, Nov 20, 2021 at 11:27:38AM +0000, Yafang Shao wrote: > 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@xxxxxxxxx> > Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx> > Acked-by: David Hildenbrand <david@xxxxxxxxxx> > Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> > Cc: Arnaldo Carvalho de Melo <arnaldo.melo@xxxxxxxxx> > Cc: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> > Cc: Michal Miroslaw <mirq-linux@xxxxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> > Cc: David Hildenbrand <david@xxxxxxxxxx> > Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > Cc: Kees Cook <keescook@xxxxxxxxxxxx> > Cc: Petr Mladek <pmladek@xxxxxxxx> > --- > 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(-) Hey all, I know this is a little late, but I recently got a report that this change was causiing older versions of perfetto to stop working. Apparently newer versions of perfetto has worked around this via the following changes: https://android.googlesource.com/platform/external/perfetto/+/c717c93131b1b6e3705a11092a70ac47c78b731d%5E%21/ https://android.googlesource.com/platform/external/perfetto/+/160a504ad5c91a227e55f84d3e5d3fe22af7c2bb%5E%21/ But for older versions of perfetto, reverting upstream commit 3087c61ed2c4 ("tools/testing/selftests/bpf: replace open-coded 16 with TASK_COMM_LEN") is necessary to get it back to working. I haven't dug very far into the details, and obviously this doesn't break with the updated perfetto, but from a high level this does seem to be a breaking-userland regression. So I wanted to reach out to see if there was more context for this breakage? I don't want to raise a unnecessary stink if this was an unfortuante but forced situation. thanks -john
