On Tue, Sep 28, 2021 at 4:58 PM Song Liu <songliubraving@xxxxxx> wrote: > > > > > On Sep 27, 2021, at 7:59 AM, Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx> wrote: > > > > Cleanup code uses while (cpu++ < cpu_cnt) for closing fds, which means > > it starts iterating from 1 for closing fds. If the first fd is -1, it > > skips over it and closes garbage fds (typically zero) in the remaining > > array. This leads to test failures for future tests when they end up > > storing fd 0 (as the slot becomes free due to close(0)) in ldimm64's BTF > > fd, ending up trying to match module BTF id with vmlinux. > > > > This was observed as spurious CI failure for the ksym_module_libbpf and > > module_attach tests. The test ends up closing fd 0 and breaking libbpf's > > assumption that module BTF fd will always be > 0, which leads to the > > kernel thinking that we are pointing to a BTF ID in vmlinux BTF. > > > > Cc: Song Liu <songliubraving@xxxxxx> > > Fixes: 025bd7c753aa (selftests/bpf: Add test for bpf_get_branch_snapshot) > > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx> > > Thanks for the fix! > > Acked-by: Song Liu <songliubraving@xxxxxx> Applied this fix to bpf-next.
