bpf: extend bpf_trace_printk to support %i
Currently, bpf_trace_printk does not support common formatting
symbol '%i' however vsprintf does and is what eventually gets
called by bpf helper. If users are used to '%i' and currently
make use of it, then bpf_trace_printk will just return with
error without dumping anything to the trace pipe, so just add
support for '%i' to the helper.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 5c6d538..3738519 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -122,8 +122,8 @@ static const struct bpf_func_proto *bpf_get_probe_write_proto(void)
}
/*
- * limited trace_printk()
- * only %d %u %x %ld %lu %lx %lld %llu %llx %p %s conversion specifiers allowed
+ * Only limited trace_printk() conversion specifiers allowed:
+ * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s
*/
BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
u64, arg2, u64, arg3)
@@ -198,7 +198,8 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
i++;
}
- if (fmt[i] != 'd' && fmt[i] != 'u' && fmt[i] != 'x')
+ if (fmt[i] != 'i' && fmt[i] != 'd' &&
+ fmt[i] != 'u' && fmt[i] != 'x')
return -EINVAL;
fmt_cnt++;
}