client: fix race condition in Echo() function#458
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booxter wants to merge 1 commit intoovn-kubernetes:mainfrom
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client: fix race condition in Echo() function#458booxter wants to merge 1 commit intoovn-kubernetes:mainfrom
booxter wants to merge 1 commit intoovn-kubernetes:mainfrom
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The Echo() function had a race condition where it would fall through
and access the reply variable after CallWithContext() returned an error
(other than ErrShutdown). This caused a data race between the calling
goroutine reading reply in reflect.DeepEqual() and the RPC readLoop
goroutine potentially still writing to it during JSON unmarshaling.
The fix adds the missing error return, matching the pattern used in
all other RPC call sites (transact, getSchema, listDbs, etc).
Race detector output before fix:
==================
WARNING: DATA RACE
Write at reflect.Value.grow() during json.Unmarshal()
github.com/cenkalti/rpc2.(*Client).readLoop()
Previous read at:
github.com/ovn-kubernetes/libovsdb/client.(*ovsdbClient).Echo()
if !reflect.DeepEqual(args, reply) { // Line 1095
==================
The race is reliably reproduced by the new TestEchoRace test which
runs concurrent Echo() calls while triggering disconnects/reconnects.
Signed-off-by: Ihar Hrachyshka <ihrachyshka@nvidia.com>
Assisted-by: opus (claude-opus-4-5-20251101)
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The Echo() function had a race condition where it would fall through
and access the reply variable after CallWithContext() returned an error
(other than ErrShutdown). This caused a data race between the calling
goroutine reading reply in reflect.DeepEqual() and the RPC readLoop
goroutine potentially still writing to it during JSON unmarshaling.
The fix adds the missing error return, matching the pattern used in
all other RPC call sites (transact, getSchema, listDbs, etc).
Race detector output before fix:
The race is reliably reproduced by the new TestEchoRace test which
runs concurrent Echo() calls while triggering disconnects/reconnects.