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Incorrect locking in replication error paths

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Former-commit-id: 1c6b57314747787958ad215826296627f9050f59
This commit is contained in:
John Sully 2020-05-24 01:57:49 -04:00
parent 51976e2be8
commit cc080de221
1 changed files with 21 additions and 1 deletions
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22
src/replication.cpp
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@ -33,6 +33,7 @@
#include "server.h"
#include "cluster.h"
#include "bio.h"
#include "aelocker.h"
#include <sys/time.h>
#include <unistd.h>
@ -1284,6 +1285,7 @@ void sendBulkToSlave(connection *conn) {
serverAssert(FCorrectThread(replica));
char buf[PROTO_IOBUF_LEN];
ssize_t nwritten, buflen;
AeLocker aeLock;
std::unique_lock<fastlock> ul(replica->lock);
/* Before sending the RDB file, we send the preamble as configured by the
@ -1295,6 +1297,8 @@ void sendBulkToSlave(connection *conn) {
serverLog(LL_VERBOSE,
"Write error sending RDB preamble to replica: %s",
connGetLastError(conn));
ul.unlock();
aeLock.arm(nullptr);
freeClient(replica);
return;
}
@ -1315,6 +1319,8 @@ void sendBulkToSlave(connection *conn) {
if (buflen <= 0) {
serverLog(LL_WARNING,"Read error sending DB to replica: %s",
(buflen == 0) ? "premature EOF" : strerror(errno));
ul.unlock();
aeLock.arm(nullptr);
freeClient(replica);
return;
}
@ -1322,6 +1328,8 @@ void sendBulkToSlave(connection *conn) {
if (connGetState(conn) != CONN_STATE_CONNECTED) {
serverLog(LL_WARNING,"Write error sending DB to replica: %s",
connGetLastError(conn));
ul.unlock();
aeLock.arm(nullptr);
freeClient(replica);
}
return;
@ -1516,6 +1524,8 @@ void updateSlavesWaitingBgsave(int bgsaveerr, int type)
while((ln = listNext(&li))) {
client *replica = (client*)ln->value;
std::unique_lock<fastlock> ul(replica->lock);
if (replica->replstate == SLAVE_STATE_WAIT_BGSAVE_START) {
startbgsave = 1;
mincapa = (mincapa == -1) ? replica->slave_capa :
@ -1562,6 +1572,7 @@ void updateSlavesWaitingBgsave(int bgsaveerr, int type)
replica->repl_ack_time = g_pserver->unixtime; /* Timeout otherwise. */
} else {
if (bgsaveerr != C_OK) {
ul.unlock();
if (FCorrectThread(replica))
freeClient(replica);
else
@ -1571,6 +1582,7 @@ void updateSlavesWaitingBgsave(int bgsaveerr, int type)
}
if ((replica->repldbfd = open(g_pserver->rdb_filename,O_RDONLY)) == -1 ||
redis_fstat(replica->repldbfd,&buf) == -1) {
ul.unlock();
if (FCorrectThread(replica))
freeClient(replica);
else
@ -1588,6 +1600,7 @@ void updateSlavesWaitingBgsave(int bgsaveerr, int type)
{
connSetWriteHandler(replica->conn,NULL);
if (connSetWriteHandler(replica->conn,sendBulkToSlave) == C_ERR) {
ul.unlock();
freeClient(replica);
continue;
}
@ -3808,6 +3821,7 @@ void replicationCron(void) {
listRewind(g_pserver->slaves,&li);
while((ln = listNext(&li))) {
client *replica = (client*)ln->value;
std::unique_lock<fastlock> ul(replica->lock);
if (replica->replstate != SLAVE_STATE_ONLINE) continue;
if (replica->flags & CLIENT_PRE_PSYNC) continue;
@ -3816,9 +3830,15 @@ void replicationCron(void) {
serverLog(LL_WARNING, "Disconnecting timedout replica: %s",
replicationGetSlaveName(replica));
if (FCorrectThread(replica))
freeClient(replica);
{
ul.release();
if (!freeClient(replica))
replica->lock.unlock(); // we didn't free so we have undo the lock we just released
}
else
{
freeClientAsync(replica);
}
}
}
}