,
On Mon, Jan 26, 2026 at 7:15 AM Leon Hwang <[email protected]> wrote: > > The log buffer of common attributes would be confusing with the one in > 'union bpf_attr' for BPF_PROG_LOAD. > > In order to clarify the usage of these two log buffers, they both can be > used for logging if: > > * They are same, including 'log_buf', 'log_level' and 'log_size'. > * One of them is missing, then another one will be used for logging. > > If they both have 'log_buf' but they are not same totally, return -EINVAL. > > Signed-off-by: Leon Hwang <[email protected]> > --- > include/linux/bpf_verifier.h | 4 +++- > kernel/bpf/log.c | 29 ++++++++++++++++++++++++++--- > kernel/bpf/syscall.c | 9 ++++++--- > 3 files changed, 35 insertions(+), 7 deletions(-) > > diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h > index 4a0c5ef296b9..7eb024e83d2d 100644 > --- a/include/linux/bpf_verifier.h > +++ b/include/linux/bpf_verifier.h > @@ -637,9 +637,11 @@ struct bpf_log_attr { > u32 log_level; > struct bpf_attrs *attrs; > u32 offsetof_log_true_size; > + struct bpf_attrs *attrs_common; > }; > > -int bpf_prog_load_log_attr_init(struct bpf_log_attr *log_attr, struct > bpf_attrs *attrs); > +int bpf_prog_load_log_attr_init(struct bpf_log_attr *log_attr, struct > bpf_attrs *attrs, > + struct bpf_attrs *attrs_common); > int bpf_log_attr_finalize(struct bpf_log_attr *log_attr, struct > bpf_verifier_log *log); > > #define BPF_MAX_SUBPROGS 256 > diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c > index 457b724c4176..c0b816e84384 100644 > --- a/kernel/bpf/log.c > +++ b/kernel/bpf/log.c > @@ -865,23 +865,41 @@ void print_insn_state(struct bpf_verifier_env *env, > const struct bpf_verifier_st > } > > static int bpf_log_attr_init(struct bpf_log_attr *log_attr, struct bpf_attrs > *attrs, u64 log_buf, > - u32 log_size, u32 log_level, int > offsetof_log_true_size) > + u32 log_size, u32 log_level, int > offsetof_log_true_size, > + struct bpf_attrs *attrs_common) > { > + const struct bpf_common_attr *common = attrs_common ? > attrs_common->attr : NULL; > + It seems the only point of struct bpf_attrs is to pass the attrs here and remember them in bpf_log_attr. It looks unnecessary. Also the cast to void and back to actual type doesn't look pretty. It seems all of it is to do two copy_to_bpfptr_offset() of log_true_size in different places, but libbpf will use only one, so let's do only one copy_to_bpfptr_offset() and simply the whole thing. struct bpf_log_attr only needs u32 offsetof_true_size; bpfptr_t uattr; No need to introduce bpf_attrs and bpf_attrs_init() either. When bpf_log_attr is inited make the choice of uattr and offset. uattr will point at either new bpf_common_attr or old bpf_attr, and offsetof_true_size will have 3 possible offsets. pw-bot: cr
