Version:           4.5 (using KDE 4.5.4) 
OS:                Linux

While using Kmail to grab mails from my imap4 account, the process kio_imap4
take all cpu after a few seconds and then kmail wait indefinitely for getting
new mail. It happens when I try to open folder containing large amount of mail
(more than a few thousands). 


Reproducible: Always

Steps to Reproduce:
1. Open Kmail
2. Open big folder on imap account


Actual Results:  
Kmail is blocked, kio_imap4 taking all cpu.

Expected Results:  
Mail refreshed.

I tried to get a backtrace of kio_imap4, using gdb kio_imap4 29404 (is this the
correct way ? ), here it is :

#0  0x00007fec550e6fd8 in ref (inWords=..., stopAtBracket=false) at
/usr/include/QtCore/qatomic_x86_64.h:121
#1  QByteArray (inWords=..., stopAtBracket=false) at
/usr/include/QtCore/qbytearray.h:382
#2  imapParser::parseOneWord (inWords=..., stopAtBracket=false) at
/usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imapparser.cpp:1981
#3  0x00007fec550ef6a5 in imapParser::parseBody (this=0x27fc080, inWords=...)
at /usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imapparser.cpp:1328
#4  0x00007fec550f01d2 in imapParser::parseFetch (this=0x27fc080, inWords=...)
at /usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imapparser.cpp:1490
#5  0x00007fec550f0f85 in imapParser::parseUntagged (this=0x27fc080,
result=...) at
/usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imapparser.cpp:495
#6  0x00007fec550f14fe in imapParser::parseLoop (this=0x27fc080) at
/usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imapparser.cpp:1743
#7  0x00007fec550dffd8 in IMAP4Protocol::get (this=0x27fc050, _url=<value
optimized out>) at /usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imap4.cpp:338
#8  0x0000003ffd3928a5 in KIO::SlaveBase::dispatch (this=0x27fc050, command=67,
data=...) at /usr/src/debug/kdelibs-4.5.4/kio/kio/slavebase.cpp:1013
#9  0x00007fec550ca844 in IMAP4Protocol::dispatch (this=0x27fc050, command=67,
data=...) at /usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imap4.cpp:1828
#10 0x0000003ffd38cbc3 in KIO::SlaveBase::dispatchLoop (this=0x27fc050) at
/usr/src/debug/kdelibs-4.5.4/kio/kio/slavebase.cpp:282
#11 0x00007fec550cb558 in kdemain (argc=<value optimized out>, argv=<value
optimized out>) at /usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imap4.cpp:131
#12 0x0000000000406bf9 in launch (argc=4, _name=0x27e28c8 "kio_imap4",
args=<value optimized out>, cwd=0x0, envc=<value optimized out>, 
    envs=<value optimized out>, reset_env=false, tty=0x0, avoid_loops=false,
startup_id_str=0x40ac76 "0")
    at /usr/src/debug/kdelibs-4.5.4/kinit/kinit.cpp:723
#13 0x00000000004077a0 in handle_launcher_request (sock=<value optimized out>,
who=<value optimized out>)
    at /usr/src/debug/kdelibs-4.5.4/kinit/kinit.cpp:1215
#14 0x0000000000407ec5 in handle_requests (waitForPid=<value optimized out>) at
/usr/src/debug/kdelibs-4.5.4/kinit/kinit.cpp:1408
#15 0x0000000000408b10 in main (argc=4, argv=0x7fff2d6d5d48,
envp=0x7fff2d6d5d70) at /usr/src/debug/kdelibs-4.5.4/kinit/kinit.cpp:1892

An another one on the same process, 30 minutes later :
#0  0x00007fec550c2f06 in deref (this=0x7fff2d6d38b0, __in_chrg=<value
optimized out>) at /usr/include/QtCore/qatomic_x86_64.h:133
#1  QByteArray::~QByteArray (this=0x7fff2d6d38b0, __in_chrg=<value optimized
out>) at /usr/include/QtCore/qbytearray.h:383
#2  0x00007fec550ef6b8 in imapParser::parseBody (this=0x27fc080, inWords=...)
at /usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imapparser.cpp:1328
#3  0x00007fec550f01d2 in imapParser::parseFetch (this=0x27fc080, inWords=...)
at /usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imapparser.cpp:1490
#4  0x00007fec550f0f85 in imapParser::parseUntagged (this=0x27fc080,
result=...) at
/usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imapparser.cpp:495
#5  0x00007fec550f14fe in imapParser::parseLoop (this=0x27fc080) at
/usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imapparser.cpp:1743
#6  0x00007fec550dffd8 in IMAP4Protocol::get (this=0x27fc050, _url=<value
optimized out>) at /usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imap4.cpp:338
#7  0x0000003ffd3928a5 in KIO::SlaveBase::dispatch (this=0x27fc050, command=67,
data=...) at /usr/src/debug/kdelibs-4.5.4/kio/kio/slavebase.cpp:1013
#8  0x00007fec550ca844 in IMAP4Protocol::dispatch (this=0x27fc050, command=67,
data=...) at /usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imap4.cpp:1828
#9  0x0000003ffd38cbc3 in KIO::SlaveBase::dispatchLoop (this=0x27fc050) at
/usr/src/debug/kdelibs-4.5.4/kio/kio/slavebase.cpp:282
#10 0x00007fec550cb558 in kdemain (argc=<value optimized out>, argv=<value
optimized out>) at /usr/src/debug/kdepimlibs-4.5.4/kioslave/imap4/imap4.cpp:131
#11 0x0000000000406bf9 in launch (argc=4, _name=0x27e28c8 "kio_imap4",
args=<value optimized out>, cwd=0x0, envc=<value optimized out>, 
    envs=<value optimized out>, reset_env=false, tty=0x0, avoid_loops=false,
startup_id_str=0x40ac76 "0")
    at /usr/src/debug/kdelibs-4.5.4/kinit/kinit.cpp:723
#12 0x00000000004077a0 in handle_launcher_request (sock=<value optimized out>,
who=<value optimized out>)
    at /usr/src/debug/kdelibs-4.5.4/kinit/kinit.cpp:1215
#13 0x0000000000407ec5 in handle_requests (waitForPid=<value optimized out>) at
/usr/src/debug/kdelibs-4.5.4/kinit/kinit.cpp:1408
#14 0x0000000000408b10 in main (argc=4, argv=0x7fff2d6d5d48,
envp=0x7fff2d6d5d70) at /usr/src/debug/kdelibs-4.5.4/kinit/kinit.cpp:1892