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authorTed Tuckman <ted.tuckman@mongodb.com>2018-09-07 15:42:20 -0400
committerEvergreen Agent <no-reply@evergreen.mongodb.com>2021-04-05 22:13:09 +0000
commit368553479c74478d15204383289d1291ad097909 (patch)
tree4c42fa95eb542601e9b383f0775959f387dcff4a
parenta1f4be4af1f316499703a80c23cf57fc7cada969 (diff)
downloadmongo-r4.0.24-rc0.tar.gz
SERVER-36926 Remove possibility of passing INT_MIN to abs() in ClusterCursorManagerr4.0.24-rc0
(cherry picked from commit 0e5b2946e1750fd4a5ac30cdc6d67d6fda94d378)
-rw-r--r--src/mongo/s/query/cluster_cursor_manager.cpp9
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 5c267bde0a1..3524e8b1e31 100644
--- a/src/mongo/s/query/cluster_cursor_manager.cpp
+++ b/src/mongo/s/query/cluster_cursor_manager.cpp
@@ -249,8 +249,13 @@ 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;