Messages in this thread | | | Date | Mon, 26 Oct 2015 14:48:11 +0800 | From | "Wangnan (F)" <> | Subject | Re: [net-next PATCH] bpf: Output error message to logbuf when loading |
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On 2015/10/26 14:36, Wang Nan wrote: > Many reason can make bpf_prog_load() return EINVAL. This patch utilizes > logbuf passed from user to deliver the actual reason of failure. > > Without this patch, people is easy to forget fixing the "version" > section in their BPF objects. > > Signed-off-by: Wang Nan <wangnan0@huawei.com> > Cc: Alexei Starovoitov <ast@kernel.org> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > Cc: David S. Miller <davem@davemloft.net> > --- > kernel/bpf/syscall.c | 41 ++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 38 insertions(+), 3 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index 687dd6c..3a0e4e7 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -574,6 +574,32 @@ struct bpf_prog *bpf_prog_get(u32 ufd) > } > EXPORT_SYMBOL_GPL(bpf_prog_get); > > +static void > +bpf_prog_load_note(union bpf_attr *attr, const char *fmt, ...) > +{ > + u32 log_level, log_size, log_len; > + char __user *log_ubuf = NULL; > + /* 64 chars should be long enough for a one line note. */ > + char log_buf[64]; > + va_list args; > + > + log_ubuf = (char __user *) (unsigned long) attr->log_buf; > + log_level = attr->log_level; > + log_size = sizeof(log_buf); > + if (attr->log_size < log_size) > + log_size = attr->log_size; > + > + if (log_level == 0 || !log_size || !log_ubuf) > + return; > + > + va_start(args, fmt); > + log_len = vscnprintf(log_buf, log_size, fmt, args);
Don't need this log_len actually. Will send a v2.
Thank you.
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