Merge branch 'bpf-fixes'

Daniel Borkmann says:

====================
Two BPF fixes

The set fixes cb_access and xdp_adjust_head bits in struct bpf_prog,
that are used for requirement checks on the program rather than f.e.
heuristics. Thus, for tail calls, we cannot make any assumptions and
are forced to set them.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

kernel/bpf/syscall.c

@@ -617,6 +617,14 @@ static void fixup_bpf_calls(struct bpf_prog *prog)
 			if (insn->imm == BPF_FUNC_xdp_adjust_head)
 				prog->xdp_adjust_head = 1;
 			if (insn->imm == BPF_FUNC_tail_call) {
+				/* If we tail call into other programs, we
+				 * cannot make any assumptions since they
+				 * can be replaced dynamically during runtime
+				 * in the program array.
+				 */
+				prog->cb_access = 1;
+				prog->xdp_adjust_head = 1;
+
 				/* mark bpf_tail_call as different opcode
 				 * to avoid conditional branch in
 				 * interpeter for every normal call