Re: Possible NULL dereferencing null pointer (src/backend/executor/nodeIncrementalSort.c)

Поиск
Список
Период
Сортировка
От Ranier Vilela
Тема Re: Possible NULL dereferencing null pointer (src/backend/executor/nodeIncrementalSort.c)
Дата
Msg-id CAEudQArQaWUrRXgz7yvMb9QwQz5B7-x_ZDtQYF4VFADvq+SnsA@mail.gmail.com
обсуждение исходный текст
Ответ на Re: Possible NULL dereferencing null pointer (src/backend/executor/nodeIncrementalSort.c)  ("David G. Johnston" <david.g.johnston@gmail.com>)
Ответы Re: Possible NULL dereferencing null pointer (src/backend/executor/nodeIncrementalSort.c)  ("David G. Johnston" <david.g.johnston@gmail.com>)
Список pgsql-hackers
Дерево обсуждения
Em sáb., 10 de out. de 2020 às 00:11, David G. Johnston <david.g.johnston@gmail.com> escreveu:
On Fri, Oct 9, 2020 at 6:41 PM Ranier Vilela <ranier.vf@gmail.com> wrote:
The problem is not only in nodeIncrementalSort.c, but in several others too, where people are using TupIsNull with ExecCopySlot.
I would call this a design flaw.
If (TupIsNull)
     ExecCopySlot

The callers, think they are using TupIsNotNullAndEmpty.
If (TupIsNotNullAndEmpty)
     ExecCopySlot

IMO both names are problematic, too data value centric, not semantic.  TupIsValid for the name and negating the existing tests would help to at least clear that part up.  Then, things operating on invalid tuples would be expected to know about both representations.  In the case of ExecCopySlot there is nothing it can do with a null representation of an invalid tuple so it would have to fail if presented one.  An assertion seems sufficient.
IHMO, assertion it is not the solution.

Steven suggested looking for some NULL pointer font above the calls.
I say that it is not necessary, there is no NULL pointer.
Whoever guarantees this is the combination, which for me is an assertion.

If (TupIsNull)
   ExecCopySlot

It works as a subject, but in release mode.
It is the equivalent of:

If (TupIsNull)
   Abort

The only problem for me is that we are running this assertion on the clients' machines.

regards,
Ranier Vilela

В списке pgsql-hackers по дате отправления:

Предыдущее
От: Michael Paquier
Дата:
Сообщение: Re: speed up unicode normalization quick check
Следующее
От: Tom Lane
Дата:
Сообщение: Re: powerpc pg_atomic_compare_exchange_u32_impl: error: comparison of integer expressions of different signedness (Re: pgsql: For all ppc compilers, implement compare_exchange and) fetch_add