Httpserver crash

[hokim]

Hello,

I am testing tutorials/http/httpserver.C of root-6.02.00 for my online monitoring application
When I click “StreamerInfo” in web browser, httpserver crashes like this.

root [0] .x httpserver.C
Info in TCivetweb::Create: Starting HTTP server on port 8080

*** Break *** segmentation violation

===========================================================
There was a crash.
This is the entire stack trace of all threads:

Thread 7 (Thread 0x7fda9d000700 (LWP 6044)):
#0 0x00007fdaa808ba4d in poll () from /lib64/libc.so.6
#1 0x00007fda9d4967fb in master_thread_run (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6205
#2 master_thread (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6273
#3 0x00007fdaa8368df3 in start_thread () from /lib64/libpthread.so.0
#4 0x00007fdaa809601d in clone () from /lib64/libc.so.6

Thread 6 (Thread 0x7fda9c7ff700 (LWP 6045)):
#0 0x00007fdaa836f5eb in recv () from /lib64/libpthread.so.0
#1 0x00007fda9d494ae3 in pull (fp=fp
entry=0x0, conn=conn
entry=0x7fda8c0008c0, buf=buf
entry=0x7fda8c000dd0 “GET”, len=len
entry=16384) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:1958
#2 0x00007fda9d494db7 in read_request (fp=fp
entry=0x0, conn=conn
entry=0x7fda8c0008c0, buf=0x7fda8c000dd0 “GET”, bufsiz=16384, nread=nread
entry=0x7fda8c000d8c) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:3509
#3 0x00007fda9d49558f in getreq (conn=conn
entry=0x7fda8c0008c0, ebuf=ebuf
entry=0x7fda9c7fcc70 “”, ebuf_len=ebuf_len
entry=100) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:5869
#4 0x00007fda9d49c597 in process_new_connection (conn=0x7fda8c0008c0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:5932
#5 worker_thread_run (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6053
#6 worker_thread (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6088
#7 0x00007fdaa8368df3 in start_thread () from /lib64/libpthread.so.0
#8 0x00007fdaa809601d in clone () from /lib64/libc.so.6

Thread 5 (Thread 0x7fda9bffe700 (LWP 6046)):
#0 0x00007fdaa836c705 in pthread_cond_wait

GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x00007fda9d49c339 in consume_socket (sp=0x7fda88000d28, ctx=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:5985
#2 worker_thread_run (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6035
#3 worker_thread (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6088
#4 0x00007fdaa8368df3 in start_thread () from /lib64/libpthread.so.0
#5 0x00007fdaa809601d in clone () from /lib64/libc.so.6

Thread 4 (Thread 0x7fda9b7fd700 (LWP 6047)):
#0 0x00007fdaa836c705 in pthread_cond_wait

GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x00007fda9d49c339 in consume_socket (sp=0x7fda90000d28, ctx=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:5985
#2 worker_thread_run (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6035
#3 worker_thread (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6088
#4 0x00007fdaa8368df3 in start_thread () from /lib64/libpthread.so.0
#5 0x00007fdaa809601d in clone () from /lib64/libc.so.6

Thread 3 (Thread 0x7fda9affc700 (LWP 6048)):
#0 0x00007fdaa836c705 in pthread_cond_wait

GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x00007fda9d49c339 in consume_socket (sp=0x7fda80000d28, ctx=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:5985
#2 worker_thread_run (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6035
#3 worker_thread (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6088
#4 0x00007fdaa8368df3 in start_thread () from /lib64/libpthread.so.0
#5 0x00007fdaa809601d in clone () from /lib64/libc.so.6

Thread 2 (Thread 0x7fda9a7fb700 (LWP 6049)):
#0 0x00007fdaa836c705 in pthread_cond_wait

GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1 0x00007fdaa4a9c0f1 in TCondition::Wait (this=this
entry=0x7fda9a7f52f0) at /home/hokim/Downloads/root-6.02.00/core/thread/src/TCondition.cxx:80
#2 0x00007fda9d48e0f2 in THttpServer::ExecuteHttp (this=this
entry=0x478c470, arg=arg
entry=0x7fda9a7f5280) at /home/hokim/Downloads/root-6.02.00/net/http/src/THttpServer.cxx:394
#3 0x00007fda9d48d789 in begin_request_handler (conn=0x7fda840008c0) at /home/hokim/Downloads/root-6.02.00/net/http/src/TCivetweb.cxx:36
#4 0x00007fda9d4998b0 in handle_request (conn=0x7fda840008c0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:5213
#5 0x00007fda9d49c690 in process_new_connection (conn=0x7fda840008c0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:5945
#6 worker_thread_run (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6053
#7 worker_thread (thread_func_param=0x478ebd0) at /home/hokim/Downloads/root-6.02.00/net/http/civetweb/civetweb.c:6088
#8 0x00007fdaa8368df3 in start_thread () from /lib64/libpthread.so.0
#9 0x00007fdaa809601d in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7fdaa9ab1940 (LWP 5768)):
#0 0x00007fdaa805d149 in waitpid () from /lib64/libc.so.6
#1 0x00007fdaa7fe2132 in do_system () from /lib64/libc.so.6
#2 0x00007fdaa7fe24e1 in system () from /lib64/libc.so.6
#3 0x00007fdaa9583fc9 in TUnixSystem::StackTrace (this=0x257a9c0) at /home/hokim/Downloads/root-6.02.00/core/unix/src/TUnixSystem.cxx:2297
#4 0x00007fdaa9585b3c in TUnixSystem::DispatchSignals (this=0x257a9c0, sig=kSigSegmentationViolation) at /home/hokim/Downloads/root-6.02.00/core/unix/src/TUnixSystem.cxx:3523
#5
#6 TBufferJSON::WorkWithElement (this=0x7fffd2e2e680, elem=0x4fe00b0, comp_type=-1) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:913
#7 0x00007fda9d48c3d8 in TBufferJSON::ClassMember (this=0x7fffd2e2e680, name=0x7fdaa50c6270 “TNamed”, typeName=, arrsize1=-1, arrsize2=-1) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:1070
#8 0x00007fdaa4fb8237 in TStreamerInfo::Streamer (this=0x3e11dd0, R(bool)=…) at /home/hokim/Downloads/root-6.02.00/io/io/src/TStreamerInfo.cxx:4855
#9 0x00007fda9d48af3f in Streamer (onfile_class=0x0, b=…, obj=0x3e11dd0, this=0x34ebc60) at /home/hokim/Downloads/root-6.02.00_build/include/TClass.h:493
#10 TBufferJSON::JsonWriteObject (this=0x7fffd2e2e680, obj=0x3e11dd0, cl=0x34ebc60) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:682
#11 0x00007fda9d48b6b8 in TBufferJSON::JsonStreamCollection (this=this
entry=0x7fffd2e2e680, col=col
entry=0x4b135d0) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:747
#12 0x00007fda9d48ae61 in TBufferJSON::JsonWriteObject (this=0x7fffd2e2e680, obj=0x4b135d0, cl=0x2e95510) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:680
#13 0x00007fda9d48b29e in TBufferJSON::JsonWriteAny (this=this
entry=0x7fffd2e2e680, obj=obj
entry=0x4b135d0, cl=cl
entry=0x2e95510) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:222
#14 0x00007fda9d48b302 in TBufferJSON::ConvertToJSON (obj=obj
entry=0x4b135d0, cl=0x2e95510, compact=compact
entry=3) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:190
#15 0x00007fda9d48b361 in TBufferJSON::ConvertToJSON (obj=obj
entry=0x4b135d0, compact=compact
entry=3) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:157
#16 0x00007fda9d4922da in TRootSniffer::ProduceJson (this=, path=, options=, res=…) at /home/hokim/Downloads/root-6.02.00/net/http/src/TRootSniffer.cxx:841
#17 0x00007fda9d492bca in TRootSniffer::Produce (this=0x3b83c60, path=0x7fda9a7f52b1 “StreamerInfo”, file=0x3ef <Address 0x3ef out of bounds>, options=0x7fda9a7f52e1 “compact=3”, ptr=
0x7fda9a7f5378: 0x0, length=
0x7fda9a7f5380: 0) at /home/hokim/Downloads/root-6.02.00/net/http/src/TRootSniffer.cxx:1176
#18 0x00007fda9d48eaec in THttpServer::ProcessRequest (this=0x478c470, arg=0x7fda9a7f5280) at /home/hokim/Downloads/root-6.02.00/net/http/src/THttpServer.cxx:513
#19 0x00007fda9d48e197 in THttpServer::ProcessRequests (this=0x478c470) at /home/hokim/Downloads/root-6.02.00/net/http/src/THttpServer.cxx:426
#20 0x00007fdaa94f0fa2 in TTimer::Notify (this=0x478bcc0) at /home/hokim/Downloads/root-6.02.00/core/base/src/TTimer.cxx:144
#21 0x00007fdaa94f0f11 in TTimer::CheckTimer (this=this
entry=0x478bcc0, now=…) at /home/hokim/Downloads/root-6.02.00/core/base/src/TTimer.cxx:131
#22 0x00007fdaa9585a89 in TUnixSystem::DispatchTimers (this=this
entry=0x257a9c0, mode=mode
entry=true) at /home/hokim/Downloads/root-6.02.00/core/unix/src/TUnixSystem.cxx:2837
#23 0x00007fdaa9586400 in TUnixSystem::DispatchOneEvent (this=0x257a9c0, pendingOnly=) at /home/hokim/Downloads/root-6.02.00/core/unix/src/TUnixSystem.cxx:1071
#24 0x00007fdaa94dff4c in TSystem::ProcessEvents (this=0x257a9c0) at /home/hokim/Downloads/root-6.02.00/core/base/src/TSystem.cxx:427
#25 0x00007fdaa9a049a0 in ?? ()
#26 0xffffffff00000000 in ?? ()
#27 0xffffffff00000000 in ?? ()
#28 0x0000000000000000 in ?? ()

The lines below might hint at the cause of the crash.
If they do not help you then please submit a bug report at
root.cern.ch/bugs. Please post the ENTIRE stack trace
from above as an attachment in addition to anything else
that might help us fixing this issue.

#6 TBufferJSON::WorkWithElement (this=0x7fffd2e2e680, elem=0x4fe00b0, comp_type=-1) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:913
#7 0x00007fda9d48c3d8 in TBufferJSON::ClassMember (this=0x7fffd2e2e680, name=0x7fdaa50c6270 “TNamed”, typeName=, arrsize1=-1, arrsize2=-1) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:1070
#8 0x00007fdaa4fb8237 in TStreamerInfo::Streamer (this=0x3e11dd0, R(bool)=…) at /home/hokim/Downloads/root-6.02.00/io/io/src/TStreamerInfo.cxx:4855
#9 0x00007fda9d48af3f in Streamer (onfile_class=0x0, b=…, obj=0x3e11dd0, this=0x34ebc60) at /home/hokim/Downloads/root-6.02.00_build/include/TClass.h:493
#10 TBufferJSON::JsonWriteObject (this=0x7fffd2e2e680, obj=0x3e11dd0, cl=0x34ebc60) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:682
#11 0x00007fda9d48b6b8 in TBufferJSON::JsonStreamCollection (this=this
entry=0x7fffd2e2e680, col=col
entry=0x4b135d0) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:747
#12 0x00007fda9d48ae61 in TBufferJSON::JsonWriteObject (this=0x7fffd2e2e680, obj=0x4b135d0, cl=0x2e95510) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:680
#13 0x00007fda9d48b29e in TBufferJSON::JsonWriteAny (this=this
entry=0x7fffd2e2e680, obj=obj
entry=0x4b135d0, cl=cl
entry=0x2e95510) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:222
#14 0x00007fda9d48b302 in TBufferJSON::ConvertToJSON (obj=obj
entry=0x4b135d0, cl=0x2e95510, compact=compact
entry=3) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:190
#15 0x00007fda9d48b361 in TBufferJSON::ConvertToJSON (obj=obj
entry=0x4b135d0, compact=compact
entry=3) at /home/hokim/Downloads/root-6.02.00/net/http/src/TBufferJSON.cxx:157
#16 0x00007fda9d4922da in TRootSniffer::ProduceJson (this=, path=, options=, res=…) at /home/hokim/Downloads/root-6.02.00/net/http/src/TRootSniffer.cxx:841
#17 0x00007fda9d492bca in TRootSniffer::Produce (this=0x3b83c60, path=0x7fda9a7f52b1 “StreamerInfo”, file=0x3ef <Address 0x3ef out of bounds>, options=0x7fda9a7f52e1 “compact=3”, ptr=
0x7fda9a7f5378: 0x0, length=
0x7fda9a7f5380: 0) at /home/hokim/Downloads/root-6.02.00/net/http/src/TRootSniffer.cxx:1176
#18 0x00007fda9d48eaec in THttpServer::ProcessRequest (this=0x478c470, arg=0x7fda9a7f5280) at /home/hokim/Downloads/root-6.02.00/net/http/src/THttpServer.cxx:513
#19 0x00007fda9d48e197 in THttpServer::ProcessRequests (this=0x478c470) at /home/hokim/Downloads/root-6.02.00/net/http/src/THttpServer.cxx:426
#20 0x00007fdaa94f0fa2 in TTimer::Notify (this=0x478bcc0) at /home/hokim/Downloads/root-6.02.00/core/base/src/TTimer.cxx:144
#21 0x00007fdaa94f0f11 in TTimer::CheckTimer (this=this
entry=0x478bcc0, now=…) at /home/hokim/Downloads/root-6.02.00/core/base/src/TTimer.cxx:131
#22 0x00007fdaa9585a89 in TUnixSystem::DispatchTimers (this=this
entry=0x257a9c0, mode=mode
entry=true) at /home/hokim/Downloads/root-6.02.00/core/unix/src/TUnixSystem.cxx:2837
#23 0x00007fdaa9586400 in TUnixSystem::DispatchOneEvent (this=0x257a9c0, pendingOnly=) at /home/hokim/Downloads/root-6.02.00/core/unix/src/TUnixSystem.cxx:1071
#24 0x00007fdaa94dff4c in TSystem::ProcessEvents (this=0x257a9c0) at /home/hokim/Downloads/root-6.02.00/core/base/src/TSystem.cxx:427
#25 0x00007fdaa9a049a0 in ?? ()
#26 0xffffffff00000000 in ?? ()
#27 0xffffffff00000000 in ?? ()
#28 0x0000000000000000 in ?? ()

Root >

Could you fix this bug?

[linev]

Hi,

I could reproduce your problem. I will fix it as soon as possible.
In fact, you do not need to access StreamerInfos at all (I left it just for backward compatibility).
When you accessing histograms, they requested in JSON format and do not requires streamer infos for decoding.
Thanks for reporting problem.

Regards,
Sergey

[hokim]

Thank you for your fix.
Actually I’m appling your contributions to our daq program by modifing online.htm and adding some javascript codes.

@linev

In fact, you do not need to access StreamerInfos at all (I left it just for backward compatibility).
When you accessing histograms, they requested in JSON format and do not requires streamer infos for decoding.
Thanks for reporting problem.

I understand what you said. But normal daq users might click “StreamerInfos” out of curiosity. It would cause serious daq crash. So I asked you to fix this bug.

Thank you very much again!

[linev]

Hi,
Fix for the problem now in repository.

I also preparing update for JavaScript/html code.
Why you want to change draw.htm file?
Are there some features missing?
Could you send me your version of draw.htm?
Regards,
Sergey