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authorAndreas Hansson <andreas.hansson@arm.com>2016-05-26 11:56:24 +0100
committerAndreas Hansson <andreas.hansson@arm.com>2016-05-26 11:56:24 +0100
commite3e808416f92d5558d17731fd31c002d84d40181 (patch)
treea1e613974a368d5680ad6e90b6701b1ed5c4b4ec /src
parent4d577ac8f18e08290e4536803d564ad85e3c3a88 (diff)
downloadgem5-e3e808416f92d5558d17731fd31c002d84d40181.tar.xz
mem: Fix memory leak in handling of deferred snoops
This patch fixes a memory leak where deferred snoop packets never got deallocated. On the call to MSHR::handleSnoop these snoops were treated as if a response will be sent, as the MSHR was pendingModified. Consequently, a copy of the packet was created and added to the MSHR targets. However, an preceeding target to the same MSHR, originally from a CPU, was serviced before the snoop, and caused the block to be invalidated. This happens for ReadExReq and UpgradeReq. Note that the original snoop will receive a response, just not from the cache in question, but instead from the cache upstream that issued the ReadExReq or UpgradeReq. Change-Id: I4ac012fbc8a46cf693ca390fe9476105d444e6f4 Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Diffstat (limited to 'src')
-rw-r--r--src/mem/cache/cache.cc14
1 files changed, 14 insertions, 0 deletions
diff --git a/src/mem/cache/cache.cc b/src/mem/cache/cache.cc
index 3048973fb..e6247823c 100644
--- a/src/mem/cache/cache.cc
+++ b/src/mem/cache/cache.cc
@@ -1954,6 +1954,19 @@ Cache::handleSnoop(PacketPtr pkt, CacheBlk *blk, bool is_timing,
}
if (!blk || !blk->isValid()) {
+ if (is_deferred) {
+ // we no longer have the block, and will not respond, but a
+ // packet was allocated in MSHR::handleSnoop and we have
+ // to delete it
+ assert(pkt->needsResponse());
+
+ // we have passed the block to a cache upstream, that
+ // cache should be responding
+ assert(pkt->cacheResponding());
+
+ delete pkt;
+ }
+
DPRINTF(CacheVerbose, "%s snoop miss for %s addr %#llx size %d\n",
__func__, pkt->cmdString(), pkt->getAddr(), pkt->getSize());
return snoop_delay;
@@ -2045,6 +2058,7 @@ Cache::handleSnoop(PacketPtr pkt, CacheBlk *blk, bool is_timing,
// responding, then we've made a copy of both the request and
// the packet, delete them here
assert(pkt->needsResponse());
+ assert(!pkt->cacheResponding());
delete pkt->req;
delete pkt;
}