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Acquire spinlock when updating 2PC slot data during logical decoding creation

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The creation of a logical decoding context in CreateDecodingContext()
updates some data of its slot for two-phase transactions if enabled by
the caller, but the code forgot to acquire a spinlock when updating
these fields like any other code paths.  This could lead to the read of
inconsistent data.

Oversight in a8fd13c.

Author: Sawada Masahiko
Discussion: https://postgr.es/m/CAD21AoAD8_fp47191LKuecjDd3DYhoQ4TaucFco1_TEr_jQ-Zw@mail.gmail.com
Backpatch-through: 15
This commit is contained in:
Michael Paquier 2023-01-12 13:41:22 +09:00
parent 38255f2d00
commit 6f25e48774
1 changed files with 2 additions and 0 deletions
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2
src/backend/replication/logical/logical.c
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@ -555,8 +555,10 @@ CreateDecodingContext(XLogRecPtr start_lsn,
/* Mark slot to allow two_phase decoding if not already marked */ /* Mark slot to allow two_phase decoding if not already marked */
if (ctx->twophase && !slot->data.two_phase) if (ctx->twophase && !slot->data.two_phase)
{ {
SpinLockAcquire(&slot->mutex);
slot->data.two_phase = true; slot->data.two_phase = true;
slot->data.two_phase_at = start_lsn; slot->data.two_phase_at = start_lsn;
SpinLockRelease(&slot->mutex);
ReplicationSlotMarkDirty(); ReplicationSlotMarkDirty();
ReplicationSlotSave(); ReplicationSlotSave();
SnapBuildSetTwoPhaseAt(ctx->snapshot_builder, start_lsn); SnapBuildSetTwoPhaseAt(ctx->snapshot_builder, start_lsn);