Re: [PATCH] Fix Uninitialized scalar variable (UNINIT) (src/backend/access/heap/heapam_handler.c)

Em ter., 25 de ago. de 2020 às 19:45, Alvaro Herrera <alvherre@2ndquadrant.com> escreveu:

On 2020-Aug-25, Ranier Vilela wrote:

> If the variable hscan->rs_cblock is InvalidBlockNumber the test can
> protect root_offsets fail.

When does that happen?

At first pass into the while loop?

hscan->rs_cblock is InvalidBlockNumber, what happens?

Other things.

1. Even heap_get_root_tuples at line 1347, be called.

Does it fill all roots_offsets?

root_offsets[offnum - 1] is secure at this point (line 1641 or is trash)?

2. hscan->rs_cbuf is constant?

if (hscan->rs_cblock != root_blkno)
{
Page page = BufferGetPage(hscan->rs_cbuf);

LockBuffer(hscan->rs_cbuf, BUFFER_LOCK_SHARE);
heap_get_root_tuples(page, root_offsets);
LockBuffer(hscan->rs_cbuf, BUFFER_LOCK_UNLOCK);

root_blkno = hscan->rs_cblock;
}

This can move outside while loop?

Am I wrong or hscan do not change?

regards,

Ranier Vilela