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fix: rare nil dereferences in lru (ele.Value.(*cacheEntry)) #529

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merged 1 commit into from
Apr 12, 2024
Merged

fix: rare nil dereferences in lru (ele.Value.(*cacheEntry)) #529

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36 changes: 20 additions & 16 deletions lru.go
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Original file line number Diff line number Diff line change
Expand Up @@ -78,7 +78,7 @@ func (c *lru) Flight(key, cmd string, ttl time.Duration, now time.Time) (v Redis

c.mu.RLock()
if kc, ok = c.store[key]; ok {
if ele, ok = kc.cache[cmd]; ok {
if ele = kc.cache[cmd]; ele != nil {
e = ele.Value.(*cacheEntry)
v = e.val
back = c.list.Back()
Expand Down Expand Up @@ -109,7 +109,7 @@ func (c *lru) Flight(key, cmd string, ttl time.Duration, now time.Time) (v Redis
kc = &keyCache{cache: make(map[string]*list.Element, 1), key: key}
c.store[key] = kc
}
if ele, ok = kc.cache[cmd]; ok {
if ele = kc.cache[cmd]; ele != nil {
if e = ele.Value.(*cacheEntry); e.val.typ == 0 || e.val.relativePTTL(now) > 0 {
atomic.AddUint32(&kc.hits, 1)
v = e.val
Expand All @@ -123,8 +123,7 @@ func (c *lru) Flight(key, cmd string, ttl time.Duration, now time.Time) (v Redis
}
atomic.AddUint32(&kc.miss, 1)
v.setExpireAt(now.Add(ttl).UnixMilli())
c.list.PushBack(&cacheEntry{cmd: cmd, kc: kc, val: v, ch: make(chan struct{})})
kc.cache[cmd] = c.list.Back()
kc.cache[cmd] = c.list.PushBack(&cacheEntry{cmd: cmd, kc: kc, val: v, ch: make(chan struct{})})
ret:
c.mu.Unlock()
return v, ce
Expand All @@ -137,7 +136,7 @@ func (c *lru) Flights(now time.Time, multi []CacheableTTL, results []RedisResult
for i, ct := range multi {
key, cmd := cmds.CacheKey(ct.Cmd)
if kc, ok := c.store[key]; ok {
if ele, ok := kc.cache[cmd]; ok {
if ele := kc.cache[cmd]; ele != nil {
e := ele.Value.(*cacheEntry)
v := e.val
if v.typ == 0 {
Expand Down Expand Up @@ -191,7 +190,7 @@ func (c *lru) Flights(now time.Time, multi []CacheableTTL, results []RedisResult
kc = &keyCache{cache: make(map[string]*list.Element, 1), key: key}
c.store[key] = kc
}
if ele, ok := kc.cache[cmd]; ok {
if ele := kc.cache[cmd]; ele != nil {
e := ele.Value.(*cacheEntry)
v := e.val
if v.typ == 0 {
Expand All @@ -211,8 +210,7 @@ func (c *lru) Flights(now time.Time, multi []CacheableTTL, results []RedisResult
atomic.AddUint32(&kc.miss, 1)
v := RedisMessage{}
v.setExpireAt(now.Add(multi[i].TTL).UnixMilli())
c.list.PushBack(&cacheEntry{cmd: cmd, kc: kc, val: v, ch: make(chan struct{})})
kc.cache[cmd] = c.list.Back()
kc.cache[cmd] = c.list.PushBack(&cacheEntry{cmd: cmd, kc: kc, val: v, ch: make(chan struct{})})
missed[j] = i
j++
}
Expand All @@ -224,7 +222,7 @@ func (c *lru) Update(key, cmd string, value RedisMessage) (pxat int64) {
var ch chan struct{}
c.mu.Lock()
if kc, ok := c.store[key]; ok {
if ele, ok := kc.cache[cmd]; ok {
if ele := kc.cache[cmd]; ele != nil {
if e := ele.Value.(*cacheEntry); e.val.typ == 0 {
pxat = value.getExpireAt()
cpttl := e.val.getExpireAt()
Expand Down Expand Up @@ -264,7 +262,7 @@ func (c *lru) Cancel(key, cmd string, err error) {
var ch chan struct{}
c.mu.Lock()
if kc, ok := c.store[key]; ok {
if ele, ok := kc.cache[cmd]; ok {
if ele := kc.cache[cmd]; ele != nil {
if e := ele.Value.(*cacheEntry); e.val.typ == 0 {
e.err = err
ch = e.ch
Expand Down Expand Up @@ -296,13 +294,17 @@ func (c *lru) GetTTL(key, cmd string) (ttl time.Duration) {
func (c *lru) purge(key string, kc *keyCache) {
if kc != nil {
for cmd, ele := range kc.cache {
if e := ele.Value.(*cacheEntry); e.val.typ != 0 { // do not delete pending entries
if delete(kc.cache, cmd); len(kc.cache) == 0 {
delete(c.store, key)
if ele != nil {
e := ele.Value.(*cacheEntry)
if e.val.typ == 0 { // do not delete pending entries
continue
}
c.list.Remove(ele)
c.size -= e.size
}
if delete(kc.cache, cmd); len(kc.cache) == 0 {
delete(c.store, key)
}
}
}
}
Expand All @@ -325,9 +327,11 @@ func (c *lru) Close(err error) {
c.mu.Lock()
for _, kc := range c.store {
for _, ele := range kc.cache {
if e := ele.Value.(*cacheEntry); e.val.typ == 0 {
e.err = err
close(e.ch)
if ele != nil {
if e := ele.Value.(*cacheEntry); e.val.typ == 0 {
e.err = err
close(e.ch)
}
}
}
}
Expand Down
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