Hallo! The GDB testsuite uses the expect program to control a GDB process (testee). These are connected via a pseudo terminal, by /hurd/term. Sooner or later, some action (of expect, of GDB, of ...) confuses the term server that much, that it apparently gets into some inconsistent internal state. The symptom is that expect is no longer able to send commands to the GDB process (and / or vice versa), and thus every test will time out. If I kill the testsuite (and thus the pseudo terminal is free again), another subsequent user of it will block, too. (For example, running a shell on it won't make it to the prompt.)
I got a backtrace, see below. Typically, new term processes that I've
seen have five threads, this one here has six, but there are also
long-running functional processes with more than ten threads, so that
shouldn't be worrying.
In this wedged state, two threads are waiting for condition signalling in
two (different) select routines; nothing else. I had a look at the two
select routines, and didn't immediatelly spot anything wrong with them.
But of course, using condition variables, the logic is spread all-over...
I will try to figure out if it's one deterministic action in the GDB
testsuite that triggers this behavior. But then, I guess whatever expect
/ GDB are doing, this shouldn't make the terminal go into an irregular
state.
How would you continue to debug this?
Thread 6 (Thread 685.17):
#0 0x01081f4c in mach_msg_trap () at
/home/buildd/build/chroot-sid/home/buildd/byhand/eglibc-2.11.2/build-tree/hurd-i386-libc/mach/mach_msg_trap.S:2
No locals.
#1 0x01082749 in __mach_msg (msg=0x129bcf8, option=2, send_size=0,
rcv_size=24, rcv_name=53, timeout=0, notify=0) at msg.c:110
ret = <value optimized out>
#2 0x0104dcff in cproc_block () at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libthreads/cprocs.c:638
msg = {msgh_bits = 4352, msgh_size = 24, msgh_remote_port = 0,
msgh_local_port = 53, msgh_seqno = 17915, msgh_id = 134863832}
waiter = <value optimized out>
new = <value optimized out>
p = 0x809dbc8
#3 0x0104f57c in hurd_condition_wait (m=0x805aa64) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libthreads/cancel-cond.c:86
cancel = <value optimized out>
__PRETTY_FUNCTION__ = "hurd_condition_wait"
c = 0x805a954
#4 0x08053b29 in pty_io_select (cred=0x80cece0, reply=49, type=0x129bf2c)
at /home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./term/ptyio.c:493
avail = 0
#5 0x0103ebc1 in _Xio_select (InHeadP=0x129bf10, OutHeadP=0x129df20) at
ioServer.c:893
io_object = 0x35
#6 0x0103dc5f in trivfs_io_server (InHeadP=0x1, OutHeadP=0x10004005) at
ioServer.c:2005
routine = 0x35
#7 0x01037eac in trivfs_demuxer (inp=0x129bf10, outp=0x129df20) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libtrivfs/demuxer.c:33
No locals.
#8 0x0805347e in demuxer (inp=0x129bf10, outp=0x129df20) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./term/main.c:69
No locals.
#9 0x01054173 in internal_demuxer (inp=0x129bf10, outheadp=0x129df20) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libports/manage-multithread.c:101
err = <value optimized out>
status = <value optimized out>
pi = 0x80cece0
link = {thread = 40, next = 0x0, prevp = 0x80cecfc, notifies =
0x805d598, interrupted_next = 0x0}
__PRETTY_FUNCTION__ = "internal_demuxer"
lock = <error reading variable lock (Cannot access memory at
address 0x1d)>
nreqthreads = <error reading variable nreqthreads (Cannot access
memory at address 0x19)>
totalthreads = <error reading variable totalthreads (Cannot access
memory at address 0x15)>
bucket = <error reading variable bucket (Cannot access memory at
address 0x11)>
demuxer = <error reading variable demuxer (Cannot access memory at
address 0xd)>
#10 0x01082e16 in __mach_msg_server_timeout (demux=0x124fd1c,
max_size=8192, rcv_name=16, option=2048, timeout=0) at msgserver.c:109
request = 0x129bf10
reply = 0x129df20
mr = 268451845
__PRETTY_FUNCTION__ = "__mach_msg_server_timeout"
#11 0x01053ec0 in thread_function (master=0) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libports/manage-multithread.c:136
timeout = 0
err = <value optimized out>
hook = 0
global_timeout = 0
thread_timeout = 0
bucket = 0x805b3b0
lock = 0
totalthreads = 5
nreqthreads = 3
#12 0x0104f068 in cthread_body (self=0x809dbc8) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libthreads/cthreads.c:300
t = 0x809dc28
#13 0x00000000 in ?? ()
No symbol table info available.
Thread 5 (Thread 685.16):
#0 0x01081f4c in mach_msg_trap () at
/home/buildd/build/chroot-sid/home/buildd/byhand/eglibc-2.11.2/build-tree/hurd-i386-libc/mach/mach_msg_trap.S:2
No locals.
#1 0x01082749 in __mach_msg (msg=0x128bf10, option=2051, send_size=32,
rcv_size=8192, rcv_name=16, timeout=0, notify=0) at msg.c:110
ret = <value optimized out>
#2 0x01082e79 in __mach_msg_server_timeout (demux=0x124fd1c,
max_size=8192, rcv_name=16, option=2048, timeout=0) at msgserver.c:151
request = 0x128df20
reply = 0x128bf10
mr = <value optimized out>
__PRETTY_FUNCTION__ = "__mach_msg_server_timeout"
#3 0x01053ec0 in thread_function (master=0) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libports/manage-multithread.c:136
timeout = 0
err = <value optimized out>
hook = 0
global_timeout = 0
thread_timeout = 0
bucket = 0x805b3b0
lock = 0
totalthreads = 5
nreqthreads = 3
#4 0x0104f068 in cthread_body (self=0x805d868) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libthreads/cthreads.c:300
t = 0x805d7f0
#5 0x00000000 in ?? ()
No symbol table info available.
Thread 4 (Thread 685.15):
#0 0x01081f4c in mach_msg_trap () at
/home/buildd/build/chroot-sid/home/buildd/byhand/eglibc-2.11.2/build-tree/hurd-i386-libc/mach/mach_msg_trap.S:2
No locals.
#1 0x01082749 in __mach_msg (msg=0x127bce8, option=2, send_size=0,
rcv_size=24, rcv_name=42, timeout=0, notify=0) at msg.c:110
ret = <value optimized out>
#2 0x0104dcff in cproc_block () at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libthreads/cprocs.c:638
msg = {msgh_bits = 38, msgh_size = 72, msgh_remote_port = 1,
msgh_local_port = 36, msgh_seqno = 21, msgh_id = 19381536}
waiter = <value optimized out>
new = <value optimized out>
p = 0x805c960
#3 0x0104f57c in hurd_condition_wait (m=0x805aa64) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libthreads/cancel-cond.c:86
cancel = <value optimized out>
__PRETTY_FUNCTION__ = "hurd_condition_wait"
c = 0x805aa38
#4 0x08051069 in trivfs_S_io_select (cred=0x80ce728, reply=38,
reply_type=17, type=0x127bf2c) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./term/users.c:2034
available = 0
#5 0x0103ebc1 in _Xio_select (InHeadP=0x127bf10, OutHeadP=0x127df20) at
ioServer.c:893
io_object = 0x2a
#6 0x0103dc5f in trivfs_io_server (InHeadP=0x1, OutHeadP=0x10004005) at
ioServer.c:2005
routine = 0x2a
#7 0x01037eac in trivfs_demuxer (inp=0x127bf10, outp=0x127df20) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libtrivfs/demuxer.c:33
No locals.
#8 0x0805347e in demuxer (inp=0x127bf10, outp=0x127df20) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./term/main.c:69
No locals.
#9 0x01054173 in internal_demuxer (inp=0x127bf10, outheadp=0x127df20) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libports/manage-multithread.c:101
err = <value optimized out>
status = <value optimized out>
pi = 0x80ce728
link = {thread = 43, next = 0x0, prevp = 0x80ce744, notifies =
0x805d1f8, interrupted_next = 0x0}
__PRETTY_FUNCTION__ = "internal_demuxer"
lock = <error reading variable lock (Cannot access memory at
address 0x1d)>
nreqthreads = <error reading variable nreqthreads (Cannot access
memory at address 0x19)>
totalthreads = <error reading variable totalthreads (Cannot access
memory at address 0x15)>
bucket = <error reading variable bucket (Cannot access memory at
address 0x11)>
demuxer = <error reading variable demuxer (Cannot access memory at
address 0xd)>
#10 0x01082e16 in __mach_msg_server_timeout (demux=0x124fd1c,
max_size=8192, rcv_name=16, option=2048, timeout=0) at msgserver.c:109
request = 0x127bf10
reply = 0x127df20
mr = 268451845
__PRETTY_FUNCTION__ = "__mach_msg_server_timeout"
#11 0x01053ec0 in thread_function (master=0) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libports/manage-multithread.c:136
timeout = 0
err = <value optimized out>
hook = 0
global_timeout = 0
thread_timeout = 0
bucket = 0x805b3b0
lock = 0
totalthreads = 5
nreqthreads = 3
#12 0x0104f068 in cthread_body (self=0x805c960) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libthreads/cthreads.c:300
t = 0x805c8e8
#13 0x00000000 in ?? ()
No symbol table info available.
Thread 3 (Thread 685.14):
#0 0x01081f4c in mach_msg_trap () at
/home/buildd/build/chroot-sid/home/buildd/byhand/eglibc-2.11.2/build-tree/hurd-i386-libc/mach/mach_msg_trap.S:2
No locals.
#1 0x01082749 in __mach_msg (msg=0x126df20, option=2051, send_size=32,
rcv_size=8192, rcv_name=16, timeout=0, notify=0) at msg.c:110
ret = <value optimized out>
#2 0x01082e79 in __mach_msg_server_timeout (demux=0x124fd1c,
max_size=8192, rcv_name=16, option=2048, timeout=0) at msgserver.c:151
request = 0x126bf10
reply = 0x126df20
mr = <value optimized out>
__PRETTY_FUNCTION__ = "__mach_msg_server_timeout"
#3 0x01053ec0 in thread_function (master=0) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libports/manage-multithread.c:136
timeout = 0
err = <value optimized out>
hook = 0
global_timeout = 0
thread_timeout = 0
bucket = 0x805b3b0
lock = 0
totalthreads = 5
nreqthreads = 3
#4 0x0104f068 in cthread_body (self=0x805bdf0) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libthreads/cthreads.c:300
t = 0x805bd78
#5 0x00000000 in ?? ()
No symbol table info available.
Thread 2 (Thread 685.13):
#0 0x01081f4c in mach_msg_trap () at
/home/buildd/build/chroot-sid/home/buildd/byhand/eglibc-2.11.2/build-tree/hurd-i386-libc/mach/mach_msg_trap.S:2
No locals.
#1 0x01082749 in __mach_msg (msg=0x125df20, option=3, send_size=32,
rcv_size=4096, rcv_name=12, timeout=0, notify=0) at msg.c:110
ret = <value optimized out>
#2 0x01082e79 in __mach_msg_server_timeout (demux=0x1093980
<msgport_server>, max_size=4096, rcv_name=12, option=0, timeout=0) at
msgserver.c:151
request = 0x125ef30
reply = 0x125df20
mr = <value optimized out>
__PRETTY_FUNCTION__ = "__mach_msg_server_timeout"
#3 0x01082f4b in __mach_msg_server (demux=0x1093980 <msgport_server>,
max_size=4096, rcv_name=12) at msgserver.c:196
No locals.
#4 0x0109394f in _hurd_msgport_receive () at msgportdemux.c:68
No locals.
#5 0x0104f068 in cthread_body (self=0x805ac08) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libthreads/cthreads.c:300
t = 0x805ab90
#6 0x00000000 in ?? ()
No symbol table info available.
Thread 1 (Thread 685.12):
#0 0x01081f4c in mach_msg_trap () at
/home/buildd/build/chroot-sid/home/buildd/byhand/eglibc-2.11.2/build-tree/hurd-i386-libc/mach/mach_msg_trap.S:2
No locals.
#1 0x01082749 in __mach_msg (msg=0x124dc70, option=2051, send_size=32,
rcv_size=8192, rcv_name=16, timeout=0, notify=0) at msg.c:110
ret = <value optimized out>
#2 0x01082e79 in __mach_msg_server_timeout (demux=0x124fd1c,
max_size=8192, rcv_name=16, option=2048, timeout=0) at msgserver.c:151
request = 0x124bc60
reply = 0x124dc70
mr = <value optimized out>
__PRETTY_FUNCTION__ = "__mach_msg_server_timeout"
#3 0x01053ec0 in thread_function (master=1) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libports/manage-multithread.c:136
timeout = 0
err = <value optimized out>
hook = 0
global_timeout = 0
thread_timeout = 0
bucket = 0x805b3b0
lock = 0
totalthreads = 5
nreqthreads = 3
#4 0x01053fd7 in ports_manage_port_operations_multithread
(bucket=0x805b3b0, demuxer=0x8053460 <demuxer>, hook=0) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./libports/manage-multithread.c:164
lock = 0
global_timeout = 0
thread_timeout = 0
nreqthreads = 3
totalthreads = 5
#5 0x08053195 in main (argc=4, argv=0x124fea4) at
/home/buildd/build/chroot-sid/home/buildd/byhand/hurd/./term/main.c:450
ourclass = 0x805b4c8
ourcntlclass = <value optimized out>
peerclass = 0x805b468
peercntlclass = 0x805b3e8
ourcntl = 0x805a9cc
peercntl = 0x805a9c8
bootstrap = 8
right = <value optimized out>
st = {st_fstype = 23, st_fsid = 3, st_ino = 82008, st_gen =
1267456677, st_rdev = 0, st_mode = 6324662, st_nlink = 1, st_uid = 0, st_gid =
0, st_size = 0, st_atim = {tv_sec = 1267456243, tv_nsec = 0}, st_mtim = {tv_sec
= 1267456243, tv_nsec = 0}, st_ctim = {
tv_sec = 1267456243, tv_nsec = 0}, st_blksize = 8192, st_blocks
= 8, st_author = 0, st_flags = 0, st_spare = {16, 136697488, 136480672, 352,
16, 136697504, 136250200, 368}}
err = <value optimized out>
openmode = 134592216
Grüße,
Thomas
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