[M3devel] Fwd: [CM3] #1080: CVSUPD server hangs if used with -C option

Tony Hosking hosking at cs.purdue.edu
Fri Jan 1 21:30:42 CET 2010


What does -C do?

On 29 Dec 2009, at 12:47, Olaf Wagner wrote:

> Any ideas? Interaction problem between threads and select?
> 
> Olaf
> 
> ----- Forwarded message from bugs at elego.de -----
>    Date: Tue, 29 Dec 2009 16:23:23 -0000
>    From: CM3 <bugs at elego.de>
> Reply-To: CM3 <bugs at elego.de>
> Subject: [CM3] #1080: CVSUPD server hangs if used with -C option
>      To: @MISSING_DOMAIN
> 
> #1080: CVSUPD server hangs if used with -C option
> -----------------------------+----------------------------------------------
>  Reporter:  rajeshvadivelu  |            Owner:  wagner
>      Type:  sw-bug          |           Status:  new
>  Priority:  high            |        Milestone:
> Component:  sys             |          Version:  5.8-RC3
>  Severity:  critical        |         Keywords:
>   Relnote:                  |     Confidential:  no
>       Org:  Collabnet       |   Estimatedhours:  0
>     Hours:  0               |         Billable:  0
> Totalhours:  0               |
> -----------------------------+----------------------------------------------
> Htr:
> Install cvsup from cm3-bin-ws-cvsup-LINUXLIBC6-5.8.4-RC4.tgz package.
> 
> Start the cvsupd server with -C option
> 
> ./cvsupd -b /data/cvsupd -C 2
> 
> Try cvsup client to connect to the sever
> 
> ./cvsup -g -L 2 /tmp/cvsupd.cfg
> 
> The client connection will hang and after sometime we will get "Inactivity timeout"
> 
> 
> Fix:
> 
> 
> 
> Env:
> 
> 
> -----------------------------+----------------------------------------------
> In a RHEL5 32bit box I was trying to run cvsupd server to mirror my cvs
> repo. I did used cm3-bin-ws-cvsup-LINUXLIBC6-5.8.4-RC4.tgz to get the
> cvsup installed.
> 
> The server starts find and there was no issues if I start the server
> without -C option.
> 
> Starting cvsupd server without -C option
> 
> $ ./cvsupd -b /u2/site/data/cvsupd
> 2009.12.29 21:31:05 IST [6225]: CVSup server started
> 2009.12.29 21:31:05 IST [6225]: Software version: 2009-08-30 21:02:46
> 2009.12.29 21:31:05 IST [6225]: Protocol version: 17.0
> 2009.12.29 21:31:05 IST [6225]: Ready to service requests
> 
> Then I did a client request as below
> 
> $ ./cvsup -g -L 2 /tmp/cvsupd.cfg
> Parsing supfile "/tmp/cvsupd.cfg"
> Connecting to myserver.com
> Connected to myserver.com
> Rejected by server: Access denied
> Will retry at 21:37:09
> 
> So the request was successful and I get a valid error message at the
> client.
> 
> But when I start the server with -C option like the one as below, requests
> from client are hanging and eventually getting "Inactivity timeout" after
> sometime.
> 
> $ ./cvsupd -b /u2/site/data/cvsupd -C 2
> 
> When ever a new client connection was made, this daemon clones another
> cvsupd process and it also hangs. So none of the client request were
> processed.
> 
> Strace of the main cvsupd server process, when a new client request was
> fired.
> 
> -----------------------------------
> select(4, [3], [], [3], {0, 39000})     = 0 (Timeout)
> select(4, [3], [], [3], {1, 0})         = 0 (Timeout)
> select(4, [3], [], [3], {1, 0})         = 0 (Timeout)
> select(4, [3], [], [3], {1, 0})         = 0 (Timeout)
> select(4, [3], [], [3], {1, 0})         = 1 (in [3], left {0, 553000})
> accept(3, {sa_family=AF_INET, sin_port=htons(51221),
> sin_addr=inet_addr("208.75.198.60")}, [16]) = 6
> setsockopt(6, SOL_SOCKET, SO_LINGER, {onoff=1, linger=1}, 8) = 0
> setsockopt(6, SOL_TCP, TCP_NODELAY, [1], 4) = 0
> fcntl64(6, F_GETFL)                     = 0x2 (flags O_RDWR)
> fcntl64(6, F_SETFL, O_RDWR|O_NONBLOCK)  = 0
> gettimeofday({1262103026, 146476}, NULL) = 0
> open("/u2/site/data/cvsupd/cvsupd.access", O_RDONLY|O_LARGEFILE) = 7
> fstat64(7, {st_mode=S_IFREG|0755, st_size=215, ...}) = 0
> _llseek(7, 0, [0], SEEK_CUR)            = 0
> fstat64(7, {st_mode=S_IFREG|0755, st_size=215, ...}) = 0
> close(7)                                = 0
> gettimeofday({1262103026, 147481}, NULL) = 0
> stat64("/u2/site/data/cvsupd/cvsupd.class", 0xbf809c04) = -1 ENOENT (No
> such file or directory)
> write(5, "\0", 1)                       = 1
> futex(0x91580f0, FUTEX_WAKE, 1)         = 1
> futex(0x9158098, FUTEX_WAKE, 1)         = 1
> futex(0x91580b8, FUTEX_WAKE, 1)         = 1
> futex(0x91580bc, FUTEX_WAIT, 5, NULL)   = -1 EAGAIN (Resource temporarily
> unavailable)
> futex(0x9158098, FUTEX_WAKE, 1)         = 0
> clone(child_stack=0,
> flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,
> child_tidptr=0xb7f43708) = 6543
> futex(0x915a484, 0x5 /* FUTEX_??? */, 1) = 1
> futex(0x915a460, FUTEX_WAKE, 1)         = 1
> futex(0x91580f0, FUTEX_WAKE, 1)         = 1
> futex(0x9158098, FUTEX_WAKE, 1)         = 1
> futex(0x91580b8, FUTEX_WAKE, 1)         = 1
> futex(0x91580bc, FUTEX_WAIT, 7, NULL)   = -1 EAGAIN (Resource temporarily
> unavailable)
> futex(0x9158098, FUTEX_WAKE, 1)         = 0
> close(6)                                = 0
> accept(3, 0xbf809e44, [16])             = -1 EAGAIN (Resource temporarily
> unavailable)
> select(4, [3], [], [3], {1, 0})         = 0 (Timeout)
> select(4, [3], [], [3], {1, 0})         = 0 (Timeout)
> select(4, [3], [], [3], {1, 0})         = 0 (Timeout)
> select(4, [3], [], [3], {1, 0})         = 0 (Timeout)
> select(4, [3], [], [3], {1, 0})         = 0 (Timeout)
> select(4, [3], [], [3], {1, 0})         = 0 (Timeout)
> select(4, [3], [], [3], {1, 0})         = 0 (Timeout)
> select(4, [3], [], [3], {1, 0})         = 0 (Timeout)
> 
> ------------------------------------
> 
> gdb backtrace of the main cvsupd server process
> 
> ------------------------------------
> 
> #0  0x00a2a402 in __kernel_vsyscall ()
> #1  0x0026efb1 in ___newselect_nocancel () from /lib/libc.so.6
> #2  0x00f8965b in Unix__select (nfds=4, readfds=0xb7f9df78,
> writefds=0xb7f9df88, exceptfds=0xb7f9df98, timeout=0xbfed9410) at
> ../src/unix/Common/UnixC.c:301
> #3  0x00f85f4b in ThreadPThread__XIOWait__CallSelect.779 (M3_Cwb5VA_nfd=4,
> M3_A4bqCj_timeout=0xbfed9410) at
> ../src/thread/PTHREAD/ThreadPThread.m3:900
> #4  0x00f85c7a in ThreadPThread__XIOWait (M3_BXP32l_self=0xb7f9400c,
> M3_Cwb5VA_fd=3, M3_AicXUJ_read=1 '\001',
> M3_CtKayy_interval=1.7976931348623157e+308, M3_AicXUJ_alertable=1 '\001')
>     at ../src/thread/PTHREAD/ThreadPThread.m3:936
> #5  0x00f8589d in SchedulerPosix__IOAlertWait (M3_Cwb5VA_fd=3,
> M3_AicXUJ_read=1 '\001', M3_CtKayy_timeoutInterval=-1) at
> ../src/thread/PTHREAD/ThreadPThread.m3:854
> #6  0x00e4b499 in TCPMisc__AcceptFrom (M3_AahksS_c=0xb7f9ca48,
> M3_DoBjMZ_peer=0xbfed9970) at ../src/POSIX/TCP.m3:458
> #7  0x0807bcbf in FSServer__Run (M3_DS26rk_self=0xb7f9c9fc) at
> ../src/FSServer.m3:153
> #8  0x080934fd in Main_M3 (M3_AcxOUs_mode=1) at ../src/Main.m3:336
> #9  0x00f717c8 in RTLinker__RunMainBody (M3_DjPxE3_m=0x80a11a0) at
> ../src/runtime/common/RTLinker.m3:399
> #10 0x00f70b82 in RTLinker__AddUnitI (M3_DjPxE3_m=0x80a11a0) at
> ../src/runtime/common/RTLinker.m3:113
> #11 0x00f70c10 in RTLinker__AddUnit (M3_DjPxE5_b=0x8090f4e) at
> ../src/runtime/common/RTLinker.m3:122
> #12 0x0804db1e in main (argc=5, argv=0xbfeda124, envp=0xbfeda13c) at
> _m3main.mc:4
> ------------------------------------------------
> 
> 
> strace of the cloned cvsupd process
> 
> -----------------------------------
> 
> futex(0x91580bc, FUTEX_WAIT, 3, NULL
> 
> -----------------------------------
> 
> gdb backtrace of the cloned cvsupd process
> 
> -----------------------------------
> 
> #0  0x00a2a402 in __kernel_vsyscall ()
> #1  0x00320146 in pthread_cond_wait@@GLIBC_2.3.2 () from
> /lib/libpthread.so.0
> #2  0x00f886e6 in ThreadPThread__pthread_cond_wait (cond=0x89c60b8,
> mutex=0x89c6098) at ../src/thread/PTHREAD/ThreadPThreadC.c:326
> #3  0x00f81d9d in ThreadPThread__XWait (M3_BXP32l_self=0xb7f9400c,
> M3_AYIbX3_m=0xb7f9c8d8, M3_Bl0jv4_c=0xb7f9c8f4, M3_AicXUJ_alertable=0
> '\0') at ../src/thread/PTHREAD/ThreadPThread.m3:238
> #4  0x00f821ae in Thread__Wait (M3_AYIbX3_m=0xb7f9c8d8,
> M3_Bl0jv4_c=0xb7f9c8f4) at ../src/thread/PTHREAD/ThreadPThread.m3:280
> #5  0x00bd4e14 in SigHandler__ChangeState (M3_BnMAgS_d=0xb7f9c4bc,
> M3_AkN0P6_state=2 '\002') at ../src/SigHandler.m3:105
> #6  0x00bd5ba6 in SigHandler__ShutDown () at ../src/SigHandler.m3:243
> #7  0x0807cbac in FSServer_M3_LINE_230.718 (L_2=0xbfed95d0) at
> ../src/FSServer.m3:231
> #8  0x0807c956 in FSServer__Run (M3_DS26rk_self=0xb7f9c9fc) at
> ../src/FSServer.m3:227
> #9  0x080934fd in Main_M3 (M3_AcxOUs_mode=1) at ../src/Main.m3:336
> #10 0x00f717c8 in RTLinker__RunMainBody (M3_DjPxE3_m=0x80a11a0) at
> ../src/runtime/common/RTLinker.m3:399
> #11 0x00f70b82 in RTLinker__AddUnitI (M3_DjPxE3_m=0x80a11a0) at
> ../src/runtime/common/RTLinker.m3:113
> #12 0x00f70c10 in RTLinker__AddUnit (M3_DjPxE5_b=0x8090f4e) at
> ../src/runtime/common/RTLinker.m3:122
> #13 0x0804db1e in main (argc=5, argv=0xbfeda124, envp=0xbfeda13c) at
> _m3main.mc:4
> 
> -------------------------------------------
> 
> So it looks like both the main and cloned cvsupd processes were waiting
> for a response from the kernel call "__kernel_vsyscall ()". Under what
> condition will this happen? Am I doing something wrong here?
> 
> -- 
> Ticket URL: <http://projects.elego.de/cm3/ticket/1080>
> CM3 <http://projects.elego.de/cm3>
> Critical Mass Modula3 Compiler
> 
> 
> ----- End forwarded message -----
> 
> 
> -- 
> Olaf Wagner -- elego Software Solutions GmbH
>               Gustav-Meyer-Allee 25 / Gebäude 12, 13355 Berlin, Germany
> phone: +49 30 23 45 86 96  mobile: +49 177 2345 869  fax: +49 30 23 45 86 95
>   http://www.elegosoft.com | Geschäftsführer: Olaf Wagner | Sitz: Berlin
> Handelregister: Amtsgericht Charlottenburg HRB 77719 | USt-IdNr: DE163214194
> 

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