Syzkaller reported a general protection fault due to a NULL pointer dereference in print_reg_state() when accessing reg->map_ptr without checking if it is NULL. The existing code assumes reg->map_ptr is always valid before dereferencing reg->map_ptr->name, reg->map_ptr->key_size, and reg->map_ptr->value_size. Fix this by adding explicit NULL checks before accessing reg->map_ptr and its members. This prevents crashes when reg->map_ptr is NULL, improving the robustness of the BPF verifier's verbose logging. Reported-by: syzbot+d36d5ae81e1b0a53ef58@syzkaller.appspotmail.com Signed-off-by: Brahmajit Das --- kernel/bpf/log.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c index f50533169cc3..5ffb8d778b92 100644 --- a/kernel/bpf/log.c +++ b/kernel/bpf/log.c @@ -704,7 +704,7 @@ static void print_reg_state(struct bpf_verifier_env *env, verbose_a("ref_obj_id=%d", reg->ref_obj_id); if (type_is_non_owning_ref(reg->type)) verbose_a("%s", "non_own_ref"); - if (type_is_map_ptr(t)) { + if (type_is_map_ptr(t) && reg->map_ptr) { if (reg->map_ptr->name[0]) verbose_a("map=%s", reg->map_ptr->name); verbose_a("ks=%d,vs=%d", -- 2.51.0