Occasionally, while reading the headers of a folder, Dovecot crashes. The visible effect in my mail client is that it will tell me a folder has a new message, but when I click on it, it will take forever to load, and there will be no new messages. When another message comes in to that folder, the folder begins to work again.
I generated a core from the latest crash, and the gdb dump is included below. After generating the core file, I removed the .imap.index* files from that folder, and it started working again.
I am using Fedora Core 1, with dovecot as an RPM (version dovecot-0.99.10.5-0.FC1). It's a Pentium 4 CPU. Let me know if there is any more information that would help you resolve this.
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Core was generated by `imap'. Program terminated with signal 11, Segmentation fault. Reading symbols from /lib/libdl.so.2...(no debugging symbols found)...done. Loaded symbols for /lib/libdl.so.2 Reading symbols from /lib/tls/libc.so.6...(no debugging symbols found)...done. Loaded symbols for /lib/tls/libc.so.6 Reading symbols from /lib/ld-linux.so.2...(no debugging symbols found)...done. Loaded symbols for /lib/ld-linux.so.2 #0 0x08088225 in hash_lookup () (gdb) bt full #0 0x08088225 in hash_lookup () No symbol table info available. #1 0x08060784 in maildir_index_sync_readonly () No symbol table info available. #2 0x0805e586 in maildir_open_mail () No symbol table info available. #3 0x0806bf8a in index_mail_next () No symbol table info available. #4 0x0806aa33 in index_storage_fetch_next () No symbol table info available. #5 0x08055f0c in imap_fetch () No symbol table info available. #6 0x0805254a in cmd_fetch () No symbol table info available. #7 0x08054260 in cmd_uid () No symbol table info available. #8 0x08054a49 in _client_reset_command () No symbol table info available. #9 0x08054ad8 in _client_input () No symbol table info available. #10 0x0808b128 in io_loop_handler_run () No symbol table info available. #11 0x00000001 in ?? () No symbol table info available. #12 0x000025c7 in ?? () No symbol table info available. #13 0x080933f2 in imap_ext_commands () No symbol table info available. #14 0x09c03b30 in ?? () ---Type <return> to continue, or q <return> to quit--- No symbol table info available. #15 0x09c03a78 in ?? () No symbol table info available. #16 0xbfefc278 in ?? () No symbol table info available. #17 0x0808d918 in o_stream_flush () No symbol table info available. Previous frame inner to this frame (corrupt stack?)