[lttng-dev] Help debugging 2.2.0rc2 core dump in lttng-sessiond

[Mathieu Desnoyers]

Hi Amit,

Can you reproduce this issue with the HEAD of lttng-tools master and
lttng-ust stable-2.2 branches ?

Thanks,

Mathieu

* Amit Margalit (AMITM at il.ibm.com) wrote:
> Hello,
> 
> I've deployed 2.2.0rc2 on one of our systems, and I've getting a core dump 
> (due to segfault) on lttng-sessiond.
> 
> Should I post all the data here, or should this be done 1x1 with one of 
> the developers?
> 
> Anyway, basic information:
> 
> Core was generated by `/usr/bin/lttng-sessiond -d --no-kernel -q'.
> Program terminated with signal 11, Segmentation fault.
> #0  ustctl_duplicate_ust_object_data (dest=dest at entry=0x7f958c000ad8, 
> src=0x0) at ustctl.c:800
> 800             if (src->handle != -1) {
> (gdb) p *dest
> $9 = (struct lttng_ust_object_data *) 0x0
> (gdb) up
> #1  0x00000000004182c6 in duplicate_channel_object 
> (ua_chan=0x7f958c0009b0, reg_chan=0x679cd0) at ust-app.c:2000
> 2000            ret = ustctl_duplicate_ust_object_data(&ua_chan->obj, 
> reg_chan->obj.ust);
> (gdb) p ua_chan->obj
> $10 = (struct lttng_ust_object_data *) 0x0
> (gdb) p *ua_chan
> $11 = {enabled = 1, handle = -1, is_sent = 0, key = 2, tracing_channel_id 
> = 0, expected_stream_count = 0, name = "channel0", '\000' <repeats 247 
> times>, obj = 0x0, attr = {
>     type = LTTNG_UST_CHAN_PER_CPU, subbuf_size = 262144, num_subbuf = 32, 
> overwrite = 0, switch_timer_interval = 0, read_timer_interval = 0, output 
> = LTTNG_UST_MMAP, chan_id = 0, 
>     uuid = '\000' <repeats 15 times>}, streams = {count = 0, head = {next 
> = 0x7f958c000b20, prev = 0x7f958c000b20}}, session = 0x677320, ctx = 
> 0x7f958c000bc0, events = 0x7f958c000920, 
>   tracefile_size = 0, tracefile_count = 0, node = {key = 0x7f958c0009d4 
> "channel0", node = {next = 0x6763a0, reverse_hash = 261524217965576192}, 
> head = {next = {next = 0x0}, func = 0}}, 
>   ust_objd_node = {key = 0, node = {next = 0x0, reverse_hash = 0}, head = 
> {next = {next = 0x0}, func = 0}}, rcu_head = {next = {next = 0x0}, func = 
> 0}}
> (gdb) p *reg_chan
> $12 = {key = 0, consumer_key = 1, streams = {next = 0x679ce0, prev = 
> 0x679ce0}, stream_list_lock = {__data = {__lock = 0, __count = 0, __owner 
> = 0, __nusers = 0, __kind = 0, __spins = 0, 
>       __list = {__prev = 0x0, __next = 0x0}}, __size = '\000' <repeats 39 
> times>, __align = 0}, node = {key = 0, node = {next = 0x0, reverse_hash = 
> 15577886586086949907}, head = {next = {
>         next = 0x0}, func = 0}}, obj = {ust = 0x0}}
> (gdb) bt
> #0  ustctl_duplicate_ust_object_data (dest=dest at entry=0x7f958c000ad8, 
> src=0x0) at ustctl.c:800
> #1  0x00000000004182c6 in duplicate_channel_object 
> (ua_chan=0x7f958c0009b0, reg_chan=0x679cd0) at ust-app.c:2000
> #2  send_channel_uid_to_ust (reg_chan=reg_chan at entry=0x679cd0, 
> app=app at entry=0x664d00, ua_sess=ua_sess at entry=0x677320, 
> ua_chan=ua_chan at entry=0x7f958c0009b0) at ust-app.c:2161
> #3  0x0000000000418f78 in create_channel_per_uid (ua_chan=0x7f958c0009b0, 
> ua_sess=0x677320, usess=<optimized out>, app=0x664d00) at ust-app.c:2263
> #4  do_create_channel (app=app at entry=0x664d00, usess=usess at entry=0x666f80, 
> ua_sess=0x677320, ua_chan=ua_chan at entry=0x7f958c0009b0) at ust-app.c:2341
> #5  0x000000000041df83 in ust_app_global_update (usess=0x666f80, 
> sock=sock at entry=20) at ust-app.c:4043
> #6  0x000000000042306f in update_ust_app (app_sock=20) at main.c:680
> #7  thread_dispatch_ust_registration (data=<optimized out>) at main.c:1465
> #8  0x00007f95974dd5f0 in start_thread () from /lib64/libpthread.so.0
> #9  0x00007f959724c87d in clone () from /lib64/libc.so.6
> #10 0x0000000000000000 in ?? ()
> (gdb) info threads
>   Id   Target Id         Frame 
>   9    Thread 0x7f9594357710 (LWP 967) 0x00007f959724cf03 in epoll_wait () 
> from /lib64/libc.so.6
>   8    Thread 0x7f9594558710 (LWP 966) 0x00007f959724cf03 in epoll_wait () 
> from /lib64/libc.so.6
>   7    Thread 0x7f9593b53710 (LWP 971) 0x00007f959724cf03 in epoll_wait () 
> from /lib64/libc.so.6
>   6    Thread 0x7f9593f55710 (LWP 969) 0x00007f959724cf03 in epoll_wait () 
> from /lib64/libc.so.6
>   5    Thread 0x7f9598d85900 (LWP 964) 0x00007f95974ddda5 in pthread_join 
> () from /lib64/libpthread.so.0
>   4    Thread 0x7f9593952710 (LWP 984) 0x00007f959724cf03 in epoll_wait () 
> from /lib64/libc.so.6
>   3    Thread 0x7f9593751710 (LWP 3941) 0x00007f95972492a9 in syscall () 
> from /lib64/libc.so.6
>   2    Thread 0x7f9593d54710 (LWP 970) 0x00007f959724cf03 in epoll_wait () 
> from /lib64/libc.so.6
> * 1    Thread 0x7f9594156710 (LWP 968) ustctl_duplicate_ust_object_data 
> (dest=dest at entry=0x7f958c000ad8, src=0x0) at ustctl.c:800
> 
> Any help is appreciated.
> 
> 
> Amit Margalit
> IBM XIV - Storage Reinvented
> XIV-NAS Development Team
> Tel. 03-689-7774
> Fax. 03-689-7230
> _______________________________________________
> lttng-dev mailing list
> lttng-dev at lists.lttng.org
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-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com