Horton

Re: Stack overflow issue

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Cc: Егор Чиндяскин <kyzevan23@mail.ru>, Richard Guo <guofenglinux@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, mahendrakar s <mahendrakarforpg@gmail.com>
Date: 2022-08-30T15:02:38Z
Lists: pgsql-hackers

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I wrote:
>> I think most likely we should report this to Snowball upstream
>> and see what they think is an appropriate fix.

> Done at [1], and I pushed the other fixes.  Thanks again for the report!

The upstream recommendation, which seems pretty sane to me, is to
simply reject any string exceeding some threshold length as not
possibly being a word.  Apparently it's common to use thresholds
as small as 64 bytes, but in the attached I used 1000 bytes.

			regards, tom lane

Commits

  1. Refactoring for CommitTransactionCommand()/AbortCurrentTransaction()

  2. Avoid recursion in MemoryContext functions

  3. Avoid stack overflow in ShowTransactionStateRec()

  4. Turn tail recursion into iteration in CommitTransactionCommand()

  5. Adjust memory allocation functions to allow sibling calls

  6. Add missing check_stack_depth() to some recursive functions

  7. In the Snowball dictionary, don't try to stem excessively-long words.

  8. Defend against stack overrun in a few more places.