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net: openvswitch: fix possible memleak on destroy flow-table
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When we destroy the flow tables which may contain the flow_mask,
so release the flow mask struct.

Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Tested-by: Greg Rose <gvrose8192@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@xpu22 @davem330
xpu22 authored and davem330 committed Nov 4, 2019
1 parent 0a3e013 commit 50b0e61
Showing 1 changed file with 98 additions and 88 deletions.
186 changes: 98 additions & 88 deletions net/openvswitch/flow_table.c
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Original file line number Diff line number Diff line change
Expand Up @@ -210,6 +210,74 @@ static int tbl_mask_array_realloc(struct flow_table *tbl, int size)
return 0;
}

static int tbl_mask_array_add_mask(struct flow_table *tbl,
struct sw_flow_mask *new)
{
struct mask_array *ma = ovsl_dereference(tbl->mask_array);
int err, ma_count = READ_ONCE(ma->count);

if (ma_count >= ma->max) {
err = tbl_mask_array_realloc(tbl, ma->max +
MASK_ARRAY_SIZE_MIN);
if (err)
return err;

ma = ovsl_dereference(tbl->mask_array);
}

BUG_ON(ovsl_dereference(ma->masks[ma_count]));

rcu_assign_pointer(ma->masks[ma_count], new);
WRITE_ONCE(ma->count, ma_count +1);

return 0;
}

static void tbl_mask_array_del_mask(struct flow_table *tbl,
struct sw_flow_mask *mask)
{
struct mask_array *ma = ovsl_dereference(tbl->mask_array);
int i, ma_count = READ_ONCE(ma->count);

/* Remove the deleted mask pointers from the array */
for (i = 0; i < ma_count; i++) {
if (mask == ovsl_dereference(ma->masks[i]))
goto found;
}

BUG();
return;

found:
WRITE_ONCE(ma->count, ma_count -1);

rcu_assign_pointer(ma->masks[i], ma->masks[ma_count -1]);
RCU_INIT_POINTER(ma->masks[ma_count -1], NULL);

kfree_rcu(mask, rcu);

/* Shrink the mask array if necessary. */
if (ma->max >= (MASK_ARRAY_SIZE_MIN * 2) &&
ma_count <= (ma->max / 3))
tbl_mask_array_realloc(tbl, ma->max / 2);
}

/* Remove 'mask' from the mask list, if it is not needed any more. */
static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask)
{
if (mask) {
/* ovs-lock is required to protect mask-refcount and
* mask list.
*/
ASSERT_OVSL();
BUG_ON(!mask->ref_count);
mask->ref_count--;

if (!mask->ref_count)
tbl_mask_array_del_mask(tbl, mask);
}
}

int ovs_flow_tbl_init(struct flow_table *table)
{
struct table_instance *ti, *ufid_ti;
Expand Down Expand Up @@ -257,7 +325,28 @@ static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu)
__table_instance_destroy(ti);
}

static void table_instance_destroy(struct table_instance *ti,
static void table_instance_flow_free(struct flow_table *table,
struct table_instance *ti,
struct table_instance *ufid_ti,
struct sw_flow *flow,
bool count)
{
hlist_del_rcu(&flow->flow_table.node[ti->node_ver]);
if (count)
table->count--;

if (ovs_identifier_is_ufid(&flow->id)) {
hlist_del_rcu(&flow->ufid_table.node[ufid_ti->node_ver]);

if (count)
table->ufid_count--;
}

flow_mask_remove(table, flow->mask);
}

static void table_instance_destroy(struct flow_table *table,
struct table_instance *ti,
struct table_instance *ufid_ti,
bool deferred)
{
Expand All @@ -274,13 +363,12 @@ static void table_instance_destroy(struct table_instance *ti,
struct sw_flow *flow;
struct hlist_head *head = &ti->buckets[i];
struct hlist_node *n;
int ver = ti->node_ver;
int ufid_ver = ufid_ti->node_ver;

hlist_for_each_entry_safe(flow, n, head, flow_table.node[ver]) {
hlist_del_rcu(&flow->flow_table.node[ver]);
if (ovs_identifier_is_ufid(&flow->id))
hlist_del_rcu(&flow->ufid_table.node[ufid_ver]);
hlist_for_each_entry_safe(flow, n, head,
flow_table.node[ti->node_ver]) {

table_instance_flow_free(table, ti, ufid_ti,
flow, false);
ovs_flow_free(flow, deferred);
}
}
Expand All @@ -305,7 +393,7 @@ void ovs_flow_tbl_destroy(struct flow_table *table)

free_percpu(table->mask_cache);
kfree_rcu(rcu_dereference_raw(table->mask_array), rcu);
table_instance_destroy(ti, ufid_ti, false);
table_instance_destroy(table, ti, ufid_ti, false);
}

struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti,
Expand Down Expand Up @@ -421,7 +509,7 @@ int ovs_flow_tbl_flush(struct flow_table *flow_table)
flow_table->count = 0;
flow_table->ufid_count = 0;

table_instance_destroy(old_ti, old_ufid_ti, true);
table_instance_destroy(flow_table, old_ti, old_ufid_ti, true);
return 0;

err_free_ti:
Expand Down Expand Up @@ -701,69 +789,14 @@ static struct table_instance *table_instance_expand(struct table_instance *ti,
return table_instance_rehash(ti, ti->n_buckets * 2, ufid);
}

static void tbl_mask_array_del_mask(struct flow_table *tbl,
struct sw_flow_mask *mask)
{
struct mask_array *ma = ovsl_dereference(tbl->mask_array);
int i, ma_count = READ_ONCE(ma->count);

/* Remove the deleted mask pointers from the array */
for (i = 0; i < ma_count; i++) {
if (mask == ovsl_dereference(ma->masks[i]))
goto found;
}

BUG();
return;

found:
WRITE_ONCE(ma->count, ma_count -1);

rcu_assign_pointer(ma->masks[i], ma->masks[ma_count -1]);
RCU_INIT_POINTER(ma->masks[ma_count -1], NULL);

kfree_rcu(mask, rcu);

/* Shrink the mask array if necessary. */
if (ma->max >= (MASK_ARRAY_SIZE_MIN * 2) &&
ma_count <= (ma->max / 3))
tbl_mask_array_realloc(tbl, ma->max / 2);
}

/* Remove 'mask' from the mask list, if it is not needed any more. */
static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask)
{
if (mask) {
/* ovs-lock is required to protect mask-refcount and
* mask list.
*/
ASSERT_OVSL();
BUG_ON(!mask->ref_count);
mask->ref_count--;

if (!mask->ref_count)
tbl_mask_array_del_mask(tbl, mask);
}
}

/* Must be called with OVS mutex held. */
void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow)
{
struct table_instance *ti = ovsl_dereference(table->ti);
struct table_instance *ufid_ti = ovsl_dereference(table->ufid_ti);

BUG_ON(table->count == 0);
hlist_del_rcu(&flow->flow_table.node[ti->node_ver]);
table->count--;
if (ovs_identifier_is_ufid(&flow->id)) {
hlist_del_rcu(&flow->ufid_table.node[ufid_ti->node_ver]);
table->ufid_count--;
}

/* RCU delete the mask. 'flow->mask' is not NULLed, as it should be
* accessible as long as the RCU read lock is held.
*/
flow_mask_remove(table, flow->mask);
table_instance_flow_free(table, ti, ufid_ti, flow, true);
}

static struct sw_flow_mask *mask_alloc(void)
Expand Down Expand Up @@ -806,29 +839,6 @@ static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl,
return NULL;
}

static int tbl_mask_array_add_mask(struct flow_table *tbl,
struct sw_flow_mask *new)
{
struct mask_array *ma = ovsl_dereference(tbl->mask_array);
int err, ma_count = READ_ONCE(ma->count);

if (ma_count >= ma->max) {
err = tbl_mask_array_realloc(tbl, ma->max +
MASK_ARRAY_SIZE_MIN);
if (err)
return err;

ma = ovsl_dereference(tbl->mask_array);
}

BUG_ON(ovsl_dereference(ma->masks[ma_count]));

rcu_assign_pointer(ma->masks[ma_count], new);
WRITE_ONCE(ma->count, ma_count +1);

return 0;
}

/* Add 'mask' into the mask list, if it is not already there. */
static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow,
const struct sw_flow_mask *new)
Expand Down

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