1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
[[!meta copyright="Copyright © 2013, 2014 Free Software Foundation, Inc."]]
[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
id="license" text="Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with no Invariant
Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license
is included in the section entitled [[GNU Free Documentation
License|/fdl]]."]]"""]]
The *term* translator implements POSIX termios discipline.
# Open Issues
## [[service_solahart_jakarta_selatan__082122541663/Term_blocking]]
## Leaks/Not Re-used/Not Terminating
[[!tag open_issue_hurd]]
### IRC, freenode, #hurd, 2013-10-14
<braunr> good news
<braunr> the terminal leak is related to privilege separation
[[tschwinge]] confirming (using `ssh -t [machine] tty`) that with privilege
separation enabled there is this problem, and once disabled it goes away.
<atheia> I love how, as an unknowing by-stander, that is somehow good news
:-)
<braunr> :)
<braunr> it's a good news because 1/ we have more knowledge about the issue
<braunr> and 2/ it may not even be a hurd bug
<braunr> but rather an openssh-on-hurd bug
<braunr> this explains why i didn't see the issue on anything else
(mach/hurd consoles, x terminals)
<braunr> and this will also indirectly solve the screen lockup issue
<teythoon> braunr: good catch :)
<braunr> s/a good news/good news/
<atheia> ah, yes, both definitely good news. Congrats on the progress.
<braunr> i remember we used to disable privilege separation in the past
<braunr> i'll have to dig what made us use it
[[news/2010-09]].
<braunr> interesting, screen seems to be affected nonetheless
<braunr> so it's something common to both screen and ssh privsep
<braunr> apparently, what sshd+privse and screen have in common is a fifo
<braunr> so it's probably a tricky hurd bug actually
### IRC, freenode, #hurd, 2013-10-16
<braunr> pflocal is leaking ports ..
<braunr> this might be what blocks terminals
* pinotree gives braunr a stick of glue
<braunr> thanks
<braunr> pflocal leaks struct sock ..
<braunr> grmbl
<braunr> hm nice, pflocal leaks each time a socket is bound and/or accepted
on
<braunr> looks like a simple ref mess
<pinotree> braunr: really?
<braunr> yes
<pinotree> a leak in pflocal feels strange, never noticed it taking lots of
memory (and it's used a lot)
<braunr> it's a port leak
<braunr> well
<braunr> no it's both a memory and port leak
<braunr> not sure which one is the root cause yet
<braunr> i guess server sockets aren't automatically unbound
<braunr> if you want to see the leak, just disable priv separation in ssh
(to avoid the terminal leak ....) and write a shell loop to start ssh
your_server echo hello
<braunr> google shows mails about the leak in the past
<braunr> i also hope it fixes the terminal leak, although i'm really not
sure :(
### IRC, freenode, #hurd, 2013-10-17
<braunr> hm nice, apparently, there is no pflocal leak
<braunr> but a libdiskfs one !
<braunr> since ext2fs enables the ifsock shortcut
<braunr> seems like it leaks a reference on sock node deletion
<teythoon> braunr: have you looked at libdiskfs/dead-name.c?
<teythoon> braunr: I think I'm hunting a very similar problem
<braunr> i'm doing it now
<teythoon> I had the problem of dead name notifications not being delivered
<braunr> wow
<teythoon> b/c I held no reference to the ports_info thing, so the dead
name handler in libports could no longer find the pi struct, so the
notification was silently dropped
<braunr> i see
<braunr> but it looks like dropping a node makes sure the associated
sockaddr has been deleted if any
<teythoon> are you sure the node is dropped in the first place?
<braunr> no
<braunr> well
<braunr> i see something happenning at the pflocal side when removing the
node
<braunr> but there is still a send right lingering somewhere
<braunr> (see why we need a global lsof :p)
<teythoon> indeed
<braunr> i'll try portinfo with that option we talked about
<teythoon> yes
<braunr> 121 => 1682: send (refs: 1)
<braunr> yep, ext2fs still has it
<teythoon> (I wonder how portinfo does that...)
<braunr> i guess it imports rights from the target task
<braunr> and see if it gets the same name as a local right
<teythoon> makes sense
<braunr> easy to check
<teythoon> well, no, it cannot do that for receive rights
<braunr> it creates an empty task just for that purpose
<braunr> and uses mach_port_extract_right
<teythoon> but it works as you described, yes
<braunr> so yes it does work for receive rights too
<teythoon> yes
<teythoon> cool :)
<braunr> so it assumes identical port names are part of the ipc interface
<braunr> something neal said we shouldn't rely on
<braunr> iirc
<teythoon> yes, I remember something like that too
<braunr> here is the strange thing
<braunr> node->sockaddr is deallocated on a dead name notification
<braunr> drop_node checks that sockaddr is null
<braunr> so how can the dead name notification occur before the node is
dropped ?
<braunr> so maybe the node is still around indeed
<braunr> apparently, libdiskfs considers the address holds a reference on
the node
<braunr> on the other hand, the server socket won't get released unless the
address gets a no-sender notification ...
<braunr> this should probably be turned into a weak reference
<braunr> teythoon: indeed, the node is leaked
<braunr> pflocal crashes when removing correctly deallocating addresses and
removing server sockets :/
<braunr> ok, pflocal bug fixed
<braunr> still have to fix the libdiskfs leak
<braunr> and libdiskfs leak fixed too
<braunr> :)
<braunr> i'll build hurd packages with my changes to make sure i don't
break something before comitting
<braunr> and see if this fixes the term issue
<braunr> looks like my patches work just fine :)
<braunr> it doesn't solve the term issue though
<braunr> so, according to portinfo, pflocal has send rights to terminals oO
<braunr> mhhhmmmmmm
<braunr> openssh seems to pass terminal file descriptors through unix
sockets when using privilege separation
<pinotree> braunr: i a write(sock, &pid, sizeof int) (or the like)?
<pinotree> *ie
<braunr> not pid, file descriptors
<braunr> SCM_RIGHTS
<pinotree> ah ok
<braunr> the socket send/recv interface does support passing mach ports
<braunr> and the leaked ports do turn into dead names when i kill terminals
<pinotree> yes, we support with a patch pochu did few years ago
<braunr> so it seems the leak is related to libpipe this time
<braunr> ok got it :)
<braunr> pflocal used copy_send instead of move_send
<braunr> \o/
<braunr> that bug was such a pain
* braunr happy
<teythoon> :)
<pinotree> speaking of it, in pflocal' S_socket_recv is it correct the
"out_flags = 0;"?
<braunr> nice catch
<braunr> although i wonder why flags are returned
<braunr> it may have been set to null to tell us that we don't want to
return flags
<braunr> pfinet seems to use it
<pinotree> but you change a local variable anyway
<braunr> yes it's not useful
<braunr> hmm
<braunr> out_flags is what gets in struct msghdr -> msg_flags
<braunr> so i guess it makes sense to fix it to *out_flags = 0, just to be
safe
<braunr> pinotree: do you want me to push it tonight along with the others
?
<pinotree> yes please
<braunr> ok
<pinotree> thanks!
<braunr> pflocal seems to not leak any memory or ports at all
<braunr> great :>
<braunr> there, patches pushed :)
### IRC, freenode, #hurd, 2014-02-07
<braunr> btw, as a note, there really are leaks in terminals
<braunr> i managed to get a term server eat up to 300M of memory yesterday
## `screen` Logout Hang
[[!tag open_issue_hurd]]
### IRC, freenode, #hurd, 2013-10-14
<braunr> i fixed term so that screen can shutdown properly
<braunr> read() wouldn't return EIO after terminal hangup
### IRC, freenode, #hurd, 2013-10-17
<braunr> and the missing EOI prevented screen from correctly shutting down
windows
|
