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Message-ID: <96d80a47-f17f-42fa-82b1-2908efbd6541@gmail.com>
Date: Thu, 12 Mar 2026 06:00:00 +0200
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Subject: Re: Speed up ICU case conversion by using ucasemap_utf8To*()
To: Jeff Davis <pgsql@j-davis.com>, Andreas Karlsson <andreas@proxel.se>,
 zengman <zengman@halodbtech.com>,
 pgsql-hackers <pgsql-hackers@postgresql.org>
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From: Alexander Lakhin <exclusion@gmail.com>
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Hello Jeff,

07.01.2026 00:10, Jeff Davis wrote:
> Committed, thank you!

I've discovered that starting from c4ff35f10, the following query:
CREATE COLLATION c (provider = icu, locale = 'icu_something');

makes asan detect (maybe dubious, but still..) stack-buffer-overflow:
==21963==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffd386d4e63 at pc 0x650cd7972a76 bp 0x7ffd386d4e00 
sp 0x7ffd386d45a8
...
Address 0x7ffd386d4e63 is located in stack of thread T0 at offset 67 in frame
     #0 0x650cd86962ef in foldcase_options (.../usr/local/pgsql/bin/postgres+0x12322ef) (BuildId: 
e441a9634858193e7358e5901e7948606ff5b1b1)

   This frame has 2 object(s):
     [48, 52) 'status' (line 993)
     [64, 67) 'lang' (line 992) <== Memory access at offset 67 overflows this variable

I use a build made with:
CC=gcc-13 CPPFLAGS="-fsanitize=address" LDFLAGS="-fsanitize=address -static-libasan" ./configure --with-icu ...

Could you please have a look?

Best regards,
Alexander
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    <div class="moz-cite-prefix">Hello Jeff,<br>
      <br>
      07.01.2026 00:10, Jeff Davis wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:cca5b4a19d68e4488ffab1f41b222a7b4c60468f.camel@j-davis.com">
      <pre wrap="" class="moz-quote-pre">Committed, thank you!
</pre>
    </blockquote>
    <br>
    I've discovered that starting from c4ff35f10, the following query:<br>
    CREATE COLLATION c (provider = icu, locale = 'icu_something');<br>
    <br>
    makes asan detect (maybe dubious, but still..)
    stack-buffer-overflow:<br>
    ==21963==ERROR: AddressSanitizer: stack-buffer-overflow on address
    0x7ffd386d4e63 at pc 0x650cd7972a76 bp 0x7ffd386d4e00 sp
    0x7ffd386d45a8<br>
    ...<br>
    Address 0x7ffd386d4e63 is located in stack of thread T0 at offset 67
    in frame<br>
        #0 0x650cd86962ef in foldcase_options
    (.../usr/local/pgsql/bin/postgres+0x12322ef) (BuildId:
    e441a9634858193e7358e5901e7948606ff5b1b1)<br>
    <br>
      This frame has 2 object(s):<br>
        [48, 52) 'status' (line 993)<br>
        [64, 67) 'lang' (line 992) &lt;== Memory access at offset 67
    overflows this variable<br>
    <br>
    I use a build made with:<br>
    CC=gcc-13 CPPFLAGS="-fsanitize=address" LDFLAGS="-fsanitize=address
    -static-libasan" ./configure --with-icu ...<br>
    <br>
    Could you please have a look?<br>
    <br>
    Best regards,<br>
    Alexander<br>
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