[PATCH 6/8] packet, clang-tidy: Packet pool buffers are not NULL

[David Gibson <david@gibson.dropbear.id.au>]

struct pool always needs a non-NULL buf field: it points either to the
actual memory used to store packets, or for vhost-user to the vhost user
memory structure which will contain the packets.  We set this pointer
when we initialise the pool.  However, clang-tidy (as of 22.1.4, at least)
doesn't realise this in packet_check_range(), causing UB warnings due to
the subtraction of ptr and p->buf.

Clue it in with an assert().

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 packet.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/packet.c b/packet.c
index 1cb74b74..7a347be6 100644
--- a/packet.c
+++ b/packet.c
@@ -51,6 +51,8 @@ static int packet_check_range(const struct pool *p, const char *ptr, size_t len,
 {
 	struct vdev_memory *memory;
 
+	assert(p->buf);
+
 	if (len > PACKET_MAX_LEN) {
 		debug("packet range length %zu (max %zu), %s:%i",
 		      len, PACKET_MAX_LEN, func, line);
-- 
2.54.0