From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:51476 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752733AbeCXSoc (ORCPT ); Sat, 24 Mar 2018 14:44:32 -0400 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w2OIds4t010168 for ; Sat, 24 Mar 2018 11:44:31 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2gwmcpgtbg-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Sat, 24 Mar 2018 11:44:31 -0700 From: Martin KaFai Lau To: CC: Alexei Starovoitov , Daniel Borkmann , Subject: [PATCH bpf-next 2/2] bpf: Add bpf_verifier_vlog() and bpf_verifier_log_needed() Date: Sat, 24 Mar 2018 11:44:23 -0700 Message-ID: <20180324184423.3053682-3-kafai@fb.com> In-Reply-To: <20180324184423.3053682-1-kafai@fb.com> References: <20180324184423.3053682-1-kafai@fb.com> MIME-Version: 1.0 Content-Type: text/plain Sender: netdev-owner@vger.kernel.org List-ID: The BTF (BPF Type Format) verifier needs to reuse the current BPF verifier log. Hence, it requires the following changes: (1) Expose log_write() in verifier.c for other users. Its name is renamed to bpf_verifier_vlog(). (2) The BTF verifier also needs to check 'log->level && log->ubuf && !bpf_verifier_log_full(log);' independently outside of the current log_write(). It is because the BTF verifier will do one-check before making multiple calls to btf_verifier_vlog to log the details of a type. Hence, this check is also re-factored to a new function bpf_verifier_log_needed(). Since it is re-factored, we can check it before va_start() in the current bpf_verifier_log_write() and verbose(). Signed-off-by: Martin KaFai Lau Acked-by: Alexei Starovoitov --- include/linux/bpf_verifier.h | 7 +++++++ kernel/bpf/verifier.c | 19 +++++++++++-------- 2 files changed, 18 insertions(+), 8 deletions(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index c30668414b22..7e61c395fddf 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -166,6 +166,11 @@ static inline bool bpf_verifier_log_full(const struct bpf_verifier_log *log) return log->len_used >= log->len_total - 1; } +static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log) +{ + return log->level && log->ubuf && !bpf_verifier_log_full(log); +} + #define BPF_MAX_SUBPROGS 256 /* single container for all structs @@ -192,6 +197,8 @@ struct bpf_verifier_env { u32 subprog_cnt; }; +void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt, + va_list args); __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env, const char *fmt, ...); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1e84e02ff733..8acd2207e412 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -168,15 +168,11 @@ struct bpf_call_arg_meta { static DEFINE_MUTEX(bpf_verifier_lock); -static void log_write(struct bpf_verifier_env *env, const char *fmt, - va_list args) +void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt, + va_list args) { - struct bpf_verifier_log *log = &env->log; unsigned int n; - if (!log->level || !log->ubuf || bpf_verifier_log_full(log)) - return; - n = vscnprintf(log->kbuf, BPF_VERIFIER_TMP_LOG_SIZE, fmt, args); WARN_ONCE(n >= BPF_VERIFIER_TMP_LOG_SIZE - 1, @@ -200,18 +196,25 @@ __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env, { va_list args; + if (!bpf_verifier_log_needed(&env->log)) + return; + va_start(args, fmt); - log_write(env, fmt, args); + bpf_verifier_vlog(&env->log, fmt, args); va_end(args); } EXPORT_SYMBOL_GPL(bpf_verifier_log_write); __printf(2, 3) static void verbose(void *private_data, const char *fmt, ...) { + struct bpf_verifier_env *env = private_data; va_list args; + if (!bpf_verifier_log_needed(&env->log)) + return; + va_start(args, fmt); - log_write(private_data, fmt, args); + bpf_verifier_vlog(&env->log, fmt, args); va_end(args); } -- 2.9.5