bpf.2: Note that unused fields and padding in bpf_attr must be zero

In a discussion regarding a potential backward incompatible change [1],
Andrii Nakryiko points out that unused bytes of bpf_attr should be
zero. Add this bit of information to the bpf(2) man page.

[1] https://lore.kernel.org/bpf/CAEf4BzbT4vQBnZzdD00SuPCDkeb4Cm=F6PLUoO_3X93UQD5hbQ@mail.gmail.com/

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>

diff --git a/man2/bpf.2 b/man2/bpf.2
index bdd97c52a8c52c1dcca70b461411e1f86b84e808..ee0072b46cad41985d179ab18d71091571697fdb 100644 (file)
--- a/man2/bpf.2
+++ b/man2/bpf.2
@@ -123,6 +123,7 @@ provided via
 which is a pointer to a union of type
 .I bpf_attr
 (see below).
+The unused fields and padding must be zeroed out before the call.
 The
 .I size
 argument is the size of the union pointed to by