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author | Ted Tuckman <ted.tuckman@mongodb.com> | 2018-09-07 15:42:20 -0400 |
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committer | Evergreen Agent <no-reply@evergreen.mongodb.com> | 2021-04-06 14:11:31 +0000 |
commit | fc3f626537400cf3b6dd89daf9ee8f50c45e03cb (patch) | |
tree | 95baabb10061e9a3a68b4c26fc50f66522d4aca2 | |
parent | 0395f6fae741624906529958d091c8762e72b594 (diff) | |
download | mongo-fc3f626537400cf3b6dd89daf9ee8f50c45e03cb.tar.gz |
SERVER-36926 Remove possibility of passing INT_MIN to abs() in ClusterCursorManager
(cherry picked from commit 0e5b2946e1750fd4a5ac30cdc6d67d6fda94d378)
(cherry picked from commit 368553479c74478d15204383289d1291ad097909)
-rw-r--r-- | src/mongo/s/query/cluster_cursor_manager.cpp | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/src/mongo/s/query/cluster_cursor_manager.cpp b/src/mongo/s/query/cluster_cursor_manager.cpp index 6ed2bc89e40..657e21850ec 100644 --- a/src/mongo/s/query/cluster_cursor_manager.cpp +++ b/src/mongo/s/query/cluster_cursor_manager.cpp @@ -245,8 +245,13 @@ StatusWith<CursorId> ClusterCursorManager::registerCursor( do { // The server has always generated positive values for CursorId (which is a signed // type), so we use std::abs() here on the prefix for consistency with this historical - // behavior. - containerPrefix = static_cast<uint32_t>(std::abs(_pseudoRandom.nextInt32())); + // behavior. If the random number generated is INT_MIN, calling std::abs on it is + // undefined behavior on 2's complement systems so we need to generate a new number. + int32_t randomNumber = 0; + do { + randomNumber = _pseudoRandom.nextInt32(); + } while (randomNumber == std::numeric_limits<int32_t>::min()); + containerPrefix = static_cast<uint32_t>(std::abs(randomNumber)); } while (_cursorIdPrefixToNamespaceMap.count(containerPrefix) > 0); _cursorIdPrefixToNamespaceMap[containerPrefix] = nss; |