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Panicking when a write txn tries to free a page which was allocated by itself #792

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Merged
ahrtr merged 1 commit into from
Jul 30, 2024
Merged

Panicking when a write txn tries to free a page which was allocated by itself #792

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11 changes: 7 additions & 4 deletions internal/freelist/shared.go
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Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,11 @@ func (t *shared) Free(txid common.Txid, p *common.Page) {
t.pending[txid] = txp
}
allocTxid, ok := t.allocs[p.Id()]
common.Verify(func() {
if allocTxid == txid {
panic(fmt.Sprintf("free: freed page (%d) was allocated by the same transaction (%d)", p.Id(), txid))
}
})
if ok {
delete(t.allocs, p.Id())
}
Expand All @@ -87,7 +92,6 @@ func (t *shared) Rollback(txid common.Txid) {
if txp == nil {
return
}
var m common.Pgids
for i, pgid := range txp.ids {
delete(t.cache, pgid)
tx := txp.alloctx[i]
Expand All @@ -98,13 +102,12 @@ func (t *shared) Rollback(txid common.Txid) {
// Pending free aborted; restore page back to alloc list.
t.allocs[pgid] = tx
} else {
// Freed page was allocated by this txn; OK to throw away.
m = append(m, pgid)
// A writing TXN should never free a page which was allocated by itself.
panic(fmt.Sprintf("rollback: freed page (%d) was allocated by the same transaction (%d)", pgid, txid))
}
}
// Remove pages from pending list and mark as free if allocated by txid.
delete(t.pending, txid)
t.mergeSpans(m)
}

func (t *shared) AddReadonlyTXID(tid common.Txid) {
Expand Down