From 6fe9c402a2b9dcd3cb1a15aed08a86338ec143f3 Mon Sep 17 00:00:00 2001 From: antirez Date: Fri, 15 Jun 2012 10:03:25 +0200 Subject: [PATCH] Fix c->reply_bytes computation in setDeferredMultiBulkLength() In order to implement reply buffer limits introduced in 2.6 and useful to close the connection under user-selected circumastances of big output buffers (for instance slow consumers in pub/sub, a blocked slave, and so forth) Redis takes a counter with the amount of used memory in objects inside the output list stored into c->reply. The computation was broken in the function setDeferredMultiBulkLength(), in the case the object was glued with the next one. This caused the c->reply_bytes field to go out of sync, be subtracted more than needed, and wrap back near to ULONG_MAX values. This commit fixes this bug and adds an assertion that is able to trap this class of problems. This problem was discovered looking at the INFO output of an unrelated issue (issue #547). --- src/networking.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/networking.c b/src/networking.c index f922e297..b3b7b94a 100644 --- a/src/networking.c +++ b/src/networking.c @@ -364,7 +364,10 @@ void setDeferredMultiBulkLength(redisClient *c, void *node, long length) { /* Only glue when the next node is non-NULL (an sds in this case) */ if (next->ptr != NULL) { + c->reply_bytes -= zmalloc_size_sds(len->ptr); + c->reply_bytes -= zmalloc_size_sds(next->ptr); len->ptr = sdscatlen(len->ptr,next->ptr,sdslen(next->ptr)); + c->reply_bytes += zmalloc_size_sds(len->ptr); listDelNode(c->reply,ln->next); } } @@ -1302,6 +1305,7 @@ int checkClientOutputBufferLimits(redisClient *c) { * called from contexts where the client can't be freed safely, i.e. from the * lower level functions pushing data inside the client output buffers. */ void asyncCloseClientOnOutputBufferLimitReached(redisClient *c) { + redisAssert(c->reply_bytes < ULONG_MAX-(1024*64)); if (c->reply_bytes == 0 || c->flags & REDIS_CLOSE_ASAP) return; if (checkClientOutputBufferLimits(c)) { sds client = getClientInfoString(c); -- GitLab