No subject
Mon Apr 8 12:38:57 PDT 2013
Cygwin and Cygwin packages that seem to have no rational explanation. Among
the most common symptoms they report are fork failures, memory leaks, and
file access denied problems. These problems, when they have been traced,
often appear to be caused by interference from other software installed on
the same PC. Security software, in particular, such as anti-virus,
anti-spyware, and firewall applications, often implements its functions by
installing hooks into various parts of the system, including both the
Explorer shell and the underlying kernel. Sometimes these hooks are not
implemented in an entirely transparent fashion, and cause changes in the
behaviour which affect the operation of other programs, such as Cygwin.
Among the software that has been found to cause difficulties are:
-
Sonic Solutions burning software containing DLA component (when DLA
disabled)
-
Norton/McAfee/Symantec antivirus or antispyware
-
Logitech webcam software with "Logitech process monitor" service
-
Kerio, Agnitum or ZoneAlarm Personal Firewall
-
Iolo System Mechanic/AntiVirus/Firewall
-
LanDesk
-
Windows Defender
-
Various programs by Wave Systems Corp using wxvault.dll, including
Embassy Trust Suite and Embassy Security Center
-
NOD32 Antivirus
-
ByteMobile laptop optimization client
-
Earthlink Total-Access
-
Spybot S&D TeaTimer
-
AR Soft RAM Disk
-
ATI Catalyst (some versions)
-
NVIDIA GeForce (some versions)
-
Windows LiveOneCare
-
Webroot Spy Sweeper with Antivirus
-
COMODO Firewall Pro
-
PC Tools Spyware Doctor
-
Avira AntiVir
-
Panda Internet Security
-
BitDefender
-
Google Desktop
-
Sophos Anti-Virus 7
-
Bufferzone from Trustware
-
Lenovo IPS Core Service (ipssvc)
-
Lenovo RapidBoot Shield
-
Credant Guardian Shield
-
AVAST (disable FILESYSTEM and BEHAVIOR realtime shields)
-
Citrix Metaframe Presentation Server/XenApp (see Citrix Support page
<http://support.citrix.com/article/CTX107825>)
-
Lavasoft Web Companion
Sometimes these problems can be worked around, by temporarily or partially
disabling the offending software. For instance, it may be possible to
disable on-access scanning in your antivirus, or configure it to ignore
files under the Cygwin installation root. Often, unfortunately, this is not
possible; even disabling the software may not work, since many applications
that hook the operating system leave their hooks installed when disabled,
and simply set them into what is intended to be a completely transparent
pass-through mode. Sometimes this pass-through is not as transparent as all
that, and the hooks still interfere with Cygwin; in these cases, it may be
necessary to uninstall the software altogether to restore normal operation.
Some of the symptoms you may experience are:
-
Random fork() failures.
Caused by hook DLLs that load themselves into every process in the
system. POSIX fork() semantics require that the memory map of the child
process must be an exact duplicate of the parent process' layout. If one=
of
these DLLs loads itself at a different base address in the child's memor=
y
space as compared to the address it was loaded at in the parent, it can =
end
up taking the space that belonged to a different DLL in the parent. When
Cygwin can't load the original DLL at that same address in the child, th=
e
fork() call has to fail.
-
File access problems.
Some programs (e.g., virus scanners with on-access scanning) scan or
otherwise operate on every file accessed by all the other software runni=
ng
on your computer. In some cases they may retain an open handle on the fi=
le
even after the software that is really using the file has closed it. Thi=
s
has been known to cause operations such as deletes, renames and moves to
fail with access denied errors. In extreme cases it has been known for
scanners to leak file handles, leading to kernel memory starvation.
-
Networking issues
Firewall software sometimes gets a bit funny about Cygwin. It's not
currently understood why; Cygwin only uses the standard Winsock2 API, bu=
t
perhaps in some less-commonly used fashion that doesn't get as well test=
ed
by the publishers of firewalls. Symptoms include mysterious failures to
connect, or corruption of network data being sent or received.
-
Memory and/or handle leaks
Some applications that hook into the Windows operating system exhibit
bugs when interacting with Cygwin that cause them to leak allocated memo=
ry
or other system resources. Symptoms include complaints about out-of-memo=
ry
errors and even virtual memory exhaustion dialog boxes from the O/S; it =
is
often possible to see the excess memory allocation using a tool such as
Task Manager or Sysinternals' Process Explorer, although interpreting th=
e
statistics they present is not always straightforward owing to
complications such as virtual memory paging and file caching.
=E2=80=8B
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Content-Type: text/html; charset=UTF-8
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<div dir=3D"ltr"><div>What a fragile pile of dung. A time bomb. Guess this =
is a good lesson to not update or upgrade a</div><div>working dev machine.=
=C2=A0</div><div><a href=3D"https://cygwin.com/faq/faq.html#faq.using.bloda=
">https://cygwin.com/faq/faq.html#faq.using.bloda</a><br></div><div><table =
border=3D"0" style=3D"font-family:'Times New Roman';width:1883px"><=
tbody><tr class=3D"" style=3D"background-color:rgb(224,224,224)"><td align=
=3D"left" valign=3D"top"><p><b>4.45.</b></p></td><td align=3D"left" valign=
=3D"top"><p>What applications have been found to interfere with Cygwin?</p>=
</td></tr><tr class=3D""><td align=3D"left" valign=3D"top"></td><td align=
=3D"left" valign=3D"top"><p>From time to time, people have reported strange=
failures and problems in Cygwin and Cygwin packages that seem to have no r=
ational explanation. Among the most common symptoms they report are fork fa=
ilures, memory leaks, and file access denied problems. These problems, when=
they have been traced, often appear to be caused by interference from othe=
r software installed on the same PC. Security software, in particular, such=
as anti-virus, anti-spyware, and firewall applications, often implements i=
ts functions by installing hooks into various parts of the system, includin=
g both the Explorer shell and the underlying kernel. Sometimes these hooks =
are not implemented in an entirely transparent fashion, and cause changes i=
n the behaviour which affect the operation of other programs, such as Cygwi=
n.</p><p>Among the software that has been found to cause difficulties are:<=
/p><div class=3D""><ul class=3D""><li class=3D""><p>Sonic Solutions burning=
software containing DLA component (when DLA disabled)</p></li><li class=3D=
""><p>Norton/McAfee/Symantec antivirus or antispyware</p></li><li class=3D"=
"><p>Logitech webcam software with "Logitech process monitor" ser=
vice</p></li><li class=3D""><p>Kerio, Agnitum or ZoneAlarm Personal Firewal=
l</p></li><li class=3D""><p>Iolo System Mechanic/AntiVirus/Firewall</p></li=
><li class=3D""><p>LanDesk</p></li><li class=3D""><p>Windows Defender</p></=
li><li class=3D""><p>Various programs by Wave Systems Corp using wxvault.dl=
l, including Embassy Trust Suite and Embassy Security Center</p></li><li cl=
ass=3D""><p>NOD32 Antivirus</p></li><li class=3D""><p>ByteMobile laptop opt=
imization client</p></li><li class=3D""><p>Earthlink Total-Access</p></li><=
li class=3D""><p>Spybot S&D TeaTimer</p></li><li class=3D""><p>AR Soft =
RAM Disk</p></li><li class=3D""><p>ATI Catalyst (some versions)</p></li><li=
class=3D""><p>NVIDIA GeForce (some versions)</p></li><li class=3D""><p>Win=
dows LiveOneCare</p></li><li class=3D""><p>Webroot Spy Sweeper with Antivir=
us</p></li><li class=3D""><p>COMODO Firewall Pro</p></li><li class=3D""><p>=
PC Tools Spyware Doctor</p></li><li class=3D""><p>Avira AntiVir</p></li><li=
class=3D""><p>Panda Internet Security</p></li><li class=3D""><p>BitDefende=
r</p></li><li class=3D""><p>Google Desktop</p></li><li class=3D""><p>Sophos=
Anti-Virus 7</p></li><li class=3D""><p>Bufferzone from Trustware</p></li><=
li class=3D""><p>Lenovo IPS Core Service (ipssvc)</p></li><li class=3D""><p=
>Lenovo RapidBoot Shield</p></li><li class=3D""><p>Credant Guardian Shield<=
/p></li><li class=3D""><p>AVAST (disable FILESYSTEM and BEHAVIOR realtime s=
hields)</p></li><li class=3D""><p>Citrix Metaframe Presentation Server/XenA=
pp (see=C2=A0<a class=3D"" href=3D"http://support.citrix.com/article/CTX107=
825" target=3D"_top">Citrix Support page</a>)</p></li><li class=3D""><p>Lav=
asoft Web Companion</p></li></ul></div><p>Sometimes these problems can be w=
orked around, by temporarily or partially disabling the offending software.=
For instance, it may be possible to disable on-access scanning in your ant=
ivirus, or configure it to ignore files under the Cygwin installation root.=
Often, unfortunately, this is not possible; even disabling the software ma=
y not work, since many applications that hook the operating system leave th=
eir hooks installed when disabled, and simply set them into what is intende=
d to be a completely transparent pass-through mode. Sometimes this pass-thr=
ough is not as transparent as all that, and the hooks still interfere with =
Cygwin; in these cases, it may be necessary to uninstall the software altog=
ether to restore normal operation.</p><p>Some of the symptoms you may exper=
ience are:</p><div class=3D""><ul class=3D""><li class=3D""><p>Random fork(=
) failures.</p><p>Caused by hook DLLs that load themselves into every proce=
ss in the system. POSIX fork() semantics require that the memory map of the=
child process must be an exact duplicate of the parent process' layout=
. If one of these DLLs loads itself at a different base address in the chil=
d's memory space as compared to the address it was loaded at in the par=
ent, it can end up taking the space that belonged to a different DLL in the=
parent. When Cygwin can't load the original DLL at that same address i=
n the child, the fork() call has to fail.</p></li><li class=3D""><p>File ac=
cess problems.</p><p>Some programs (e.g., virus scanners with on-access sca=
nning) scan or otherwise operate on every file accessed by all the other so=
ftware running on your computer. In some cases they may retain an open hand=
le on the file even after the software that is really using the file has cl=
osed it. This has been known to cause operations such as deletes, renames a=
nd moves to fail with access denied errors. In extreme cases it has been kn=
own for scanners to leak file handles, leading to kernel memory starvation.=
</p></li><li class=3D""><p>Networking issues</p><p>Firewall software someti=
mes gets a bit funny about Cygwin. It's not currently understood why; C=
ygwin only uses the standard Winsock2 API, but perhaps in some less-commonl=
y used fashion that doesn't get as well tested by the publishers of fir=
ewalls. Symptoms include mysterious failures to connect, or corruption of n=
etwork data being sent or received.</p></li><li class=3D""><p>Memory and/or=
handle leaks</p><p>Some applications that hook into the Windows operating =
system exhibit bugs when interacting with Cygwin that cause them to leak al=
located memory or other system resources. Symptoms include complaints about=
out-of-memory errors and even virtual memory exhaustion dialog boxes from =
the O/S; it is often possible to see the excess memory allocation using a t=
ool such as Task Manager or Sysinternals' Process Explorer, although in=
terpreting the statistics they present is not always straightforward owing =
to complications such as virtual memory paging and file caching.</p></li></=
ul></div></td></tr></tbody></table></div>=E2=80=8B</div>
--001a11439d02a13b7c0525e25895--
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