Commit 4633c9e0 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller

net-packet: fix null pointer exception in rollover mode

Rollover can be enabled as flag or mode. Allocate state in both cases.
This solves a NULL pointer exception in fanout_demux_rollover on
referencing po->rollover if using mode rollover.

Also make sure that in rollover mode each silo is tried (contrary
to rollover flag, where the main socket is excluded after an initial
try_self).

Tested:
  Passes tools/testing/net/psock_fanout.c, which tests both modes and
  flag. My previous tests were limited to bench_rollover, which only
  stresses the flag. The test now completes safely. it still gives an
  error for mode rollover, because it does not expect the new headroom
  (ROOM_NORMAL) requirement. I will send a separate patch to the test.

Fixes: 0648ab70 ("packet: rollover prepare: per-socket state")
Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>

----

I should have run this test and caught this before submission, of
course. Apologies for the oversight.
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c91d4606
...@@ -1389,7 +1389,7 @@ static unsigned int fanout_demux_rollover(struct packet_fanout *f, ...@@ -1389,7 +1389,7 @@ static unsigned int fanout_demux_rollover(struct packet_fanout *f,
unsigned int idx, bool try_self, unsigned int idx, bool try_self,
unsigned int num) unsigned int num)
{ {
struct packet_sock *po, *po_next; struct packet_sock *po, *po_next, *po_skip = NULL;
unsigned int i, j, room = ROOM_NONE; unsigned int i, j, room = ROOM_NONE;
po = pkt_sk(f->arr[idx]); po = pkt_sk(f->arr[idx]);
...@@ -1399,12 +1399,13 @@ static unsigned int fanout_demux_rollover(struct packet_fanout *f, ...@@ -1399,12 +1399,13 @@ static unsigned int fanout_demux_rollover(struct packet_fanout *f,
if (room == ROOM_NORMAL || if (room == ROOM_NORMAL ||
(room == ROOM_LOW && !fanout_flow_is_huge(po, skb))) (room == ROOM_LOW && !fanout_flow_is_huge(po, skb)))
return idx; return idx;
po_skip = po;
} }
i = j = min_t(int, po->rollover->sock, num - 1); i = j = min_t(int, po->rollover->sock, num - 1);
do { do {
po_next = pkt_sk(f->arr[i]); po_next = pkt_sk(f->arr[i]);
if (po_next != po && !po_next->pressure && if (po_next != po_skip && !po_next->pressure &&
packet_rcv_has_room(po_next, skb) == ROOM_NORMAL) { packet_rcv_has_room(po_next, skb) == ROOM_NORMAL) {
if (i != j) if (i != j)
po->rollover->sock = i; po->rollover->sock = i;
...@@ -1549,7 +1550,8 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags) ...@@ -1549,7 +1550,8 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
if (po->fanout) if (po->fanout)
return -EALREADY; return -EALREADY;
if (type_flags & PACKET_FANOUT_FLAG_ROLLOVER) { if (type == PACKET_FANOUT_ROLLOVER ||
(type_flags & PACKET_FANOUT_FLAG_ROLLOVER)) {
po->rollover = kzalloc(sizeof(*po->rollover), GFP_KERNEL); po->rollover = kzalloc(sizeof(*po->rollover), GFP_KERNEL);
if (!po->rollover) if (!po->rollover)
return -ENOMEM; return -ENOMEM;
......
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