Cyrus IMAP 2.3.6: alignment error

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From: Alex Deiter Bugzilla-Id: 2861 Version: 2.3.x Owner: Ken Murchison

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From: Alex Deiter

Hi,

Cyrus IMAP 2.3.6 have a bug on 64bit BIG-endian arch:

program terminated by signal BUS (invalid address alignment) Current function is mailbox_read_index_header 946 ntohll(((bit64 )(mailbox->index_base+OFFSET_HIGHESTMODSEQ_64))); (dbx) where =>[1] mailbox_read_index_header(mailbox = 0xffffffff7fffd858), line 946 in "mailbox.c" [2] mailbox_open_index(mailbox = 0xffffffff7fffd858), line 675 in "mailbox.c" [3] cmd_select(tag = 0x1002ac920 "s", cmd = 0x1002ac9a0 "Select", name = 0x1002aca20 "INBOX"), line 3388 in "imapd.c" [4] cmdloop(), line 1650 in "imapd.c" [5] service_main(argc = 1, argv = 0x100299ba0, envp = 0xffffffff7ffffcb8), line 789 in "imapd.c" [6] main(argc = 1, argv = 0xffffffff7ffffca8, envp = 0xffffffff7ffffcb8), line 532 in "service.c"

Thanks!

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Attachment-Id: 452 From: Ken Murchison Type: text/plain File: 64bit_alignment.diff

64bit alignment patch

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From: Ken Murchison

Which compiler are you using? I can't reproduce with gcc on Solaris 8

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From: Alex Deiter

i'm used Sun Studio 11 on Solaris 9.

This patch broken build:

cc -c -I.. -I./../lib -I./../sieve -D_LARGEFILE64_SOURCE -D_REENTRANT -I/usr/local/include -DKRB5_HEIMDAL -I/usr/local/include -DHAVE_CONFIG_H -xarch=v9 -xO5 -xspace -D_LARGEFILE64_SOURCE -D_REENTRANT -I/usr/local/include -KPIC -DPIC \ index.c "mailbox.h", line 112: warning: unnamed struct member "index.c", line 236: improper member use: index_base "index.c", line 1951: warning: argument #6 is incompatible with prototype: prototype: pointer to int : "./../lib/charset.h", line 75 argument : pointer to unsigned int "index.c", line 3533: warning: argument #2 is incompatible with prototype: prototype: pointer to const char : "./../lib/message_uuid.h", line 61 argument : pointer to unsigned char cc: acomp failed for index.c gmake[1]: [index.o] Error 2 gmake[1]: Leaving directory `/home/devel/build/mail/cyrus-imapd/64/cyrus-imapd-2.3.7/imap' gmake: [all] Error 1 *** Error code 2

Stop.

Thanks a lot!

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From: James Goodlet

Hi,

I've just tripped across this issue too. We're running 2.2.13 on Solaris 10 (64 bit, sparc, gcc 4.0.3, now gcc 4.1.2), and attempting to migrate to 2.3.8. We're getting bus errors in imapd in mailbox_read_index_header as it tries to read mailbox->highestmodseq from an existing header file.
The back trace is:

0 mailbox_read_index_header (mailbox=0xffbfd5e0) at mailbox.c:947

1 0x00043548 in mailbox_open_index (mailbox=0xffbfd5e0) at mailbox.c:677

2 0x0002a1d8 in cmd_select (tag=0x15e920 ".", cmd=0x15e990 "Select",

name=0x15ea00 "inbox") at imapd.c:3451

3 0x0002e694 in cmdloop () at imapd.c:1656

4 0x00030f98 in service_main (argc=1278976, argv=0x1567c0, envp=0xffbff89c)

at imapd.c:797

5 0x0001b6ec in main (argc=<value optimized out>,

argv=<value optimized out>, envp=0xffbff89c) at service.c:539

and the specific line which throws the error is (on mailbox.c:947):

946 #ifdef HAVE_LONG_LONG_INT 947 mailbox->highestmodseq = 948 ntohll(((bit64 )(mailbox->index_base+OFFSET_HIGHESTMODSEQ_64))); 949 #else

The bus error is caused by the attempt to read a 64 bit value from a non-64 bit aligned address.
index_base is fine with a value of 0xfe8d0000, but the problem comes because OFFSET_HIGHESTMODSEQ_64 is defined to be 68, hence the resulting address doesn't align on a 64 bit boundary (i.e. mod 64 will equal 32 not 0).

Reading around, I found this similar bug report for Dovecot

<http://www.dovecot.org/list/dovecot/2005-January/005925.html&gt;

which has a useful summary and link to a discussion on a GCC bugs forum and suggests strongly that the problem is made apparent when gcc's optimisation is turned on.

Whilst I haven't tested your proposed patch, I don't see that it will fix the problem of the OFFSET_HIGHESTMODSEQ_64 offset causing the non-64 bit aligned addresses. I'll put together a patch (based on the approach in the Dovecot message), since I both need to go to 2.3.8 and to get benefit from the "64 bit" quota patch. I doubt my patch will be very elegant, but I'll submit it here when I've completed it, which should be in a couple of hours.

James

For reference, here's the dump of *mailbox at the point of the crash:

(gdb) p *mailbox $3 = { header_fd = 10, index_fd = 13, cache_fd = 14, header_base = 0xfed90000 "?\002\213\rCyrus mailbox header\n\"The best thing about this system was that it had lots of goals.\"\n\t--Jim Morris on Andrew\nuser.test\t14292238454f6335\nNotJunk $NotJunk JunkRecorded Forwarded MessageJunkMailLev"..., header_len = 253, index_base = 0xfe8d0000 "", index_len = 16384, cache_base = 0xfe8b0000 "", cache_len = 65536, cache_size = 50656, header_lock_count = 0, index_lock_count = 0, seen_lock_count = 0, pop_lock_count = 0, header_ino = 11504296, index_mtime = 1174669417, index_ino = 10154440, index_size = 3616, name = 0x156ff0 "user.test", path = 0x15ea70 "/tmp/mailstoretmp/spool1/user/test", mpath = 0x0, acl = 0x157008 "test\tlrswipcda\t", myrights = 2047, uniqueid = 0x159a18 "14292238454f6335", flagname = {0x156a98 "NotJunk", 0x157038 "$NotJunk", 0x157050 "JunkRecorded", 0x157068 "Forwarded", 0x159a38 "MessageJunkMailLevel", 0x157080 "$Forwarded", 0x156aa8 "Junk", 0x156ab8 "$Junk", 0x157098 "Redirected", 0x0 <repeats 119 times>}, generation_no = 15, format = 0, minor_version = 9, start_offset = 96, record_size = 80, exists = 44, last_appenddate = 1174291915, last_uid = 4416, quota_mailbox_used = 472087, pop3_last_login = 0, uidvalidity = 0, deleted = 0, answered = 0, flagged = 0, dirty = 0, options = 0, leaked_cache_records = 0, highestmodseq = 0, spares = {0, 0, 0, 0}, quota = { root = 0x157020 "user.test", used = 0, limit = 0 }, examining = 1, keepingseen = 0, allseen = 0, recentuid = 0 }

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Attachment-Id: 534 From: James Goodlet Type: text/plain File: cyrus-imapd-2.3.8-highestmodseq-64bit-alignment-patch

highestmodseq 64bit alignment patch

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Attachment-Id: 561 From: Ken Murchison Type: text/plain File: 64bit_alignment.patch

alternate highestmodeseq 64bit alignment patch

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From: James Goodlet

Yes, that works fine. Built, installed, tested on Solaris 10 on sparcv9 architecture running with 64 bit kernel space, and 32/64-bit user space. Cyrus IMAPD is built as a 32 bit application using gcc 4.1.2. The 64 bit extensions are working fine now.

Thanks for the prompt response, and keep up the good work.

James

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From: Ken Murchison

Applied alternate patch to CVS