gzip compressed mbox: Panic: file istream-zlib.c: line 421 (i_stream_zlib_seek): assertion failed: (ret == -1)

[Aki Tuomi]

> On July 5, 2017 at 6:38 PM Anton Yuzhaninov <citrin at citrin.ru> wrote:
> 
> 
> Hello,
> 
> I use mbox compressed by gzip as read-only folder (using zlib plugin).
> 
> I have errors in logs:
> Panic: file istream-zlib.c: line 416 (i_stream_zlib_seek): assertion
> failed: (ret == -1)
> and can't read messages in MUA.
> 
> IMAP commands to reproduce a bug:
> 
> 1 SELECT "compressed.gz"
> 2 UID fetch 2 BODY.PEEK[]
> # sleep 5
> 3 UID fetch 2 BODY.PEEK[]
> # repeat sleep/fetch until assert (a few fetches need to trigger bug,
> probably because of caching)
> 
> The bug appeared in 2.2.26 and still can be reproduced (in 2.2.31)
> 
> Using 'git bisect' was not productive (a lot of build errors), but I've
> found that reverting this commit:
> https://github.com/dovecot/core/commit/6a1110d8757bb72fd90f4fe0857fd3aeaf8920ff
> 
> "fixes" problem for me, so I suppose the bug was introduced in this commit.
> 
> -- 
> Best Regards,
> Anton Yuzhaninov

If you only revert the bit here


-		} while (i_stream_read(&stream->istream) > 0);
+		} while ((ret = i_stream_read(&stream->istream)) > 0);

in src/lib-compression/istream-zlib.c

does it still fix the issue?

Aki