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[teamsyncd]: Fix bug when removing selectable in select function (son…
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…ic-net#665)

In the current implementation, the selectable is removed inside the
select() function. However, the select function will retrieve multiple
file descriptors at one time. If the file descriptor is removed, it
will cause segmentation fault.

Signed-off-by: Shu0T1an ChenG <shuche@microsoft.com>
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Shuotian Cheng authored Nov 1, 2018
1 parent 2c83b68 commit 863b69c
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Showing 3 changed files with 53 additions and 18 deletions.
52 changes: 40 additions & 12 deletions teamsyncd/teamsync.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -24,13 +24,34 @@ TeamSync::TeamSync(DBConnector *db, DBConnector *stateDb, Select *select) :
{
}

void TeamSync::doSelectableTask()
{
/* Start to track the new team instances */
for (auto s : m_selectablesToAdd)
{
m_select->addSelectable(m_teamSelectables[s].get());
}

m_selectablesToAdd.clear();

/* No longer track the deprecated team instances */
for (auto s : m_selectablesToRemove)
{
m_select->removeSelectable(m_teamSelectables[s].get());
m_teamSelectables.erase(s);
}

m_selectablesToRemove.clear();
}

void TeamSync::onMsg(int nlmsg_type, struct nl_object *obj)
{
struct rtnl_link *link = (struct rtnl_link *)obj;
if ((nlmsg_type != RTM_NEWLINK) && (nlmsg_type != RTM_DELLINK))
return;

string lagName = rtnl_link_get_name(link);

/* Listens to LAG messages */
char *type = rtnl_link_get_type(link);
if (!type || (strcmp(type, TEAM_DRV_NAME) != 0))
Expand Down Expand Up @@ -63,35 +84,40 @@ void TeamSync::addLag(const string &lagName, int ifindex, bool admin_state,
lagName.c_str(), admin_state ? "up" : "down", oper_state ? "up" : "down");

/* Return when the team instance has already been tracked */
if (m_teamPorts.find(lagName) != m_teamPorts.end())
if (m_teamSelectables.find(lagName) != m_teamSelectables.end())
return;

/* Start track the team instance */
auto sync = make_shared<TeamPortSync>(lagName, ifindex, &m_lagMemberTable);
m_select->addSelectable(sync.get());
m_teamPorts[lagName] = sync;

fvVector.clear();
FieldValueTuple s("state", "ok");
fvVector.push_back(s);
m_stateLagTable.set(lagName, fvVector);

/* Create the team instance */
auto sync = make_shared<TeamPortSync>(lagName, ifindex, &m_lagMemberTable);
m_teamSelectables[lagName] = sync;
m_selectablesToAdd.insert(lagName);
}

void TeamSync::removeLag(const string &lagName)
{
/* Delete all members */
auto selectable = m_teamSelectables[lagName];
for (auto it : selectable->m_lagMembers)
{
m_lagMemberTable.del(lagName + ":" + it.first);
}

/* Delete the LAG */
m_lagTable.del(lagName);

SWSS_LOG_INFO("Remove %s", lagName.c_str());

/* Return when the team instance hasn't been tracked before */
if (m_teamPorts.find(lagName) == m_teamPorts.end())
if (m_teamSelectables.find(lagName) == m_teamSelectables.end())
return;

/* No longer track the current team instance */
m_select->removeSelectable(m_teamPorts[lagName].get());
m_teamPorts.erase(lagName);
m_stateLagTable.del(lagName);
m_selectablesToRemove.insert(lagName);
}

const struct team_change_handler TeamSync::TeamPortSync::gPortChangeHandler = {
Expand All @@ -114,7 +140,8 @@ TeamSync::TeamPortSync::TeamPortSync(const string &lagName, int ifindex,
}

int err = team_init(m_team, ifindex);
if (err) {
if (err)
{
team_free(m_team);
m_team = NULL;
SWSS_LOG_ERROR("Unable to init team socket");
Expand All @@ -123,7 +150,8 @@ TeamSync::TeamPortSync::TeamPortSync(const string &lagName, int ifindex,
}

err = team_change_handler_register(m_team, &gPortChangeHandler, this);
if (err) {
if (err)
{
team_free(m_team);
m_team = NULL;
SWSS_LOG_ERROR("Unable to register port change event");
Expand Down
17 changes: 11 additions & 6 deletions teamsyncd/teamsync.h
Original file line number Diff line number Diff line change
Expand Up @@ -18,12 +18,12 @@ class TeamSync : public NetMsg
public:
TeamSync(DBConnector *db, DBConnector *stateDb, Select *select);

/*
* Listens to RTM_NEWLINK and RTM_DELLINK to undestand if there is a new
* team device
*/
/* Listen to RTM_NEWLINK, RTM_DELLINK to track team devices */
virtual void onMsg(int nlmsg_type, struct nl_object *obj);

/* Handle all selectables add/removal events */
void doSelectableTask();

class TeamPortSync : public Selectable
{
public:
Expand All @@ -35,6 +35,8 @@ class TeamSync : public NetMsg
int getFd() override;
void readData() override;

/* member_name -> enabled|disabled */
std::map<std::string, bool> m_lagMembers;
protected:
int onChange();
static int teamdHandler(struct team_handle *th, void *arg,
Expand All @@ -45,7 +47,6 @@ class TeamSync : public NetMsg
struct team_handle *m_team;
std::string m_lagName;
int m_ifindex;
std::map<std::string, bool> m_lagMembers; /* map[ifname] = status (enabled|disabled) */
};

protected:
Expand All @@ -58,7 +59,11 @@ class TeamSync : public NetMsg
ProducerStateTable m_lagTable;
ProducerStateTable m_lagMemberTable;
Table m_stateLagTable;
std::map<std::string, std::shared_ptr<TeamPortSync> > m_teamPorts;

/* Store selectables needed to be updated in doSelectableTask function */
std::set<std::string> m_selectablesToAdd;
std::set<std::string> m_selectablesToRemove;
std::map<std::string, std::shared_ptr<TeamPortSync> > m_teamSelectables;
};

}
Expand Down
2 changes: 2 additions & 0 deletions teamsyncd/teamsyncd.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,8 @@ int main(int argc, char **argv)
{
Selectable *temps;
s.select(&temps);

sync.doSelectableTask();
}
}
catch (const std::exception& e)
Expand Down

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