On Fri, Jun 20, 2025 at 03:34:14PM +0200, Jiri Olsa wrote: > On Wed, Apr 30, 2025 at 02:42:49PM +0100, Alan Maguire wrote: > > Recently issues were observed with module BTF deduplication failures > > [1]. Add a dedup selftest that ensures that core kernel types are > > referenced from split BTF as base BTF types. To do this use bpf_testmod > > functions which utilize core kernel types, specifically > > > > ssize_t > > bpf_testmod_test_write(struct file *file, struct kobject *kobj, > > struct bin_attribute *bin_attr, > > char *buf, loff_t off, size_t len); > > > > __bpf_kfunc struct sock *bpf_kfunc_call_test3(struct sock *sk); > > > > __bpf_kfunc void bpf_kfunc_call_test_pass_ctx(struct __sk_buff *skb); > > > > For each of these ensure that the types they reference - > > struct file, struct kobject, struct bin_attr etc - are in base BTF. > > Note that because bpf_testmod.ko is built with distilled base BTF > > the associated reference types - i.e. the PTR that points at a > > "struct file" - will be in split BTF. As a result the test resolves > > typedef and pointer references and verifies the pointed-at or > > typedef'ed type is in base BTF. Because we use BTF from > > /sys/kernel/btf/bpf_testmod relocation has occurred for the > > referenced types and they will be base - not distilled base - types. > > > > For large-scale dedup issues, we see such types appear in split BTF and > > as a result this test fails. Hence it is proposed as a test which will > > fail when large-scale dedup issues have occurred. > > > > [1] https://lore.kernel.org/dwarves/CAADnVQL+-LiJGXwxD3jEUrOonO-fX0SZC8496dVzUXvfkB7gYQ@xxxxxxxxxxxxxx/ > > > > Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx> > > hi Alan, > this one started to fail in my tests.. it's likely some screw up in > my environment, but I haven't found the cause yet, I'm using the > pahole 1.30 .. just cheking if it's known issue already ;-) hum, it might be my gcc-14 .. will upgrade jirka
