Content-Type: multipart/alternative;
 boundary="------------wcQ5sXIyHIjI0xKHo0R02Rlc"
Message-ID: <f9591c60-b241-5f03-711d-171ded31650a@gmail.com>
Date: Sat, 18 Mar 2023 10:00:01 +0300
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.4.2
Subject: Re: BUG #17847: Unaligned memory access in ltree_gist
Content-Language: en-US
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-bugs@lists.postgresql.org, Alexander Korotkov <aekorotkov@gmail.com>
References: <17847-171232970bea406b@postgresql.org>
 <3966266.1678995315@sss.pgh.pa.us>
From: Alexander Lakhin <exclusion@gmail.com>
In-Reply-To: <3966266.1678995315@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/f9591c60-b241-5f03-711d-171ded31650a%40gmail.com>
Precedence: bulk

This is a multi-part message in MIME format.
--------------wcQ5sXIyHIjI0xKHo0R02Rlc
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit

16.03.2023 22:35, Tom Lane wrote:
> I wonder which other opclasses besides ltree have the same issue.

I found no other similar places: siglen is also accepted by opclasses
gist__intbig_ops, gist_hstore_ops, gist_trgm_ops, tsvector_ops,
which implementations use functions
_intbig_alloc, ghstore_alloc, gtrgm_alloc, gtsvector_alloc,
and none of them adds siglen to a pointer.
Quick testing confirms that.

(gist__ltree_ops uses ltree_gist_alloc(), but the problematic branch
"if (left) ..." not reached for gist__ltree_ops)

Best regards,
Alexander
--------------wcQ5sXIyHIjI0xKHo0R02Rlc
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: 7bit

<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  </head>
  <body>
    <div class="moz-cite-prefix">16.03.2023 22:35, Tom Lane wrote:<br>
    </div>
    <blockquote type="cite" cite="mid:3966266.1678995315@sss.pgh.pa.us">
      <pre class="moz-quote-pre" wrap="">I wonder which other opclasses besides ltree have the same issue.
</pre>
    </blockquote>
    <br>
    I found no other similar places: siglen is also accepted by
    opclasses<br>
    gist__intbig_ops, gist_hstore_ops, gist_trgm_ops, tsvector_ops, <br>
    which implementations use functions<br>
    _intbig_alloc, ghstore_alloc, gtrgm_alloc, gtsvector_alloc,<br>
    and none of them adds siglen to a pointer.<br>
    Quick testing confirms that.<br>
    <br>
    (gist__ltree_ops uses ltree_gist_alloc(), but the problematic branch<br>
    "if (left) ..." not reached for gist__ltree_ops)<br>
    <br>
    Best regards,<br>
    Alexander<span style="font-family:monospace"><br>
    </span>
  </body>
</html>

--------------wcQ5sXIyHIjI0xKHo0R02Rlc--