In many others runs it worked fine, bit I again hung with 50 threads (gdb) info threads 66 Thread 0x421d6950 (LWP 5330) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 65 Thread 0x429d7950 (LWP 5331) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 64 Thread 0x431d8950 (LWP 5332) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 63 Thread 0x439d9950 (LWP 5333) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 62 Thread 0x441da950 (LWP 5334) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 61 Thread 0x449db950 (LWP 5335) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 60 Thread 0x451dc950 (LWP 5336) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 59 Thread 0x459dd950 (LWP 5337) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 58 Thread 0x461de950 (LWP 5338) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 57 Thread 0x469df950 (LWP 5339) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 56 Thread 0x4132a950 (LWP 5364) 0x00007fa620df8482 in select () from /lib/libc.so.6 55 Thread 0x471e0950 (LWP 5365) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 54 Thread 0x479e1950 (LWP 5367) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 53 Thread 0x47a22950 (LWP 5368) 0x00007fa6220b0e7b in sigwait () from /lib/libpthread.so.0 52 Thread 0x4136b950 (LWP 5406) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 51 Thread 0x47a63950 (LWP 5408) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 50 Thread 0x47aa4950 (LWP 5410) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 49 Thread 0x47ae5950 (LWP 5414) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 48 Thread 0x47b26950 (LWP 5415) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 47 Thread 0x47b67950 (LWP 5416) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 46 Thread 0x47ba8950 (LWP 5417) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 45 Thread 0x47be9950 (LWP 5419) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 44 Thread 0x47c2a950 (LWP 5422) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 43 Thread 0x47c6b950 (LWP 5423) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 42 Thread 0x47cac950 (LWP 5424) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 41 Thread 0x47ced950 (LWP 5426) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 40 Thread 0x47d2e950 (LWP 5428) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 39 Thread 0x47d6f950 (LWP 5429) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 38 Thread 0x47db0950 (LWP 5432) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 37 Thread 0x47df1950 (LWP 5433) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 36 Thread 0x47e32950 (LWP 5437) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 35 Thread 0x47e73950 (LWP 5439) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 34 Thread 0x47eb4950 (LWP 5443) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 33 Thread 0x47ef5950 (LWP 5444) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 32 Thread 0x47f36950 (LWP 5445) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 31 Thread 0x47f77950 (LWP 5446) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 30 Thread 0x47fb8950 (LWP 5448) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 29 Thread 0x47ff9950 (LWP 5449) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 28 Thread 0x4803a950 (LWP 5451) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 27 Thread 0x4807b950 (LWP 5453) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 26 Thread 0x480bc950 (LWP 5455) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 25 Thread 0x480fd950 (LWP 5457) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 24 Thread 0x4813e950 (LWP 5460) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 23 Thread 0x4817f950 (LWP 5463) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 22 Thread 0x481c0950 (LWP 5465) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 21 Thread 0x48201950 (LWP 5466) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 20 Thread 0x48242950 (LWP 5468) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 19 Thread 0x48283950 (LWP 5469) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 18 Thread 0x482c4950 (LWP 5471) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 17 Thread 0x48305950 (LWP 5472) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 16 Thread 0x48346950 (LWP 5477) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 15 Thread 0x48387950 (LWP 5488) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 14 Thread 0x483c8950 (LWP 5497) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 13 Thread 0x48409950 (LWP 5498) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 12 Thread 0x4844a950 (LWP 5499) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 11 Thread 0x4848b950 (LWP 5501) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 10 Thread 0x484cc950 (LWP 5502) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 ---Type <return> to continue, or q <return> to quit--- 9 Thread 0x4850d950 (LWP 5504) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 8 Thread 0x4854e950 (LWP 5505) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 7 Thread 0x4858f950 (LWP 5506) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 6 Thread 0x485d0950 (LWP 5507) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 5 Thread 0x48611950 (LWP 5529) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 4 Thread 0x413ac950 (LWP 5531) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 3 Thread 0x413ed950 (LWP 5532) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 2 Thread 0x4142e950 (LWP 8568) 0x00007fa6220ad2d9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0 1 Thread 0x7fa6224d06f0 (LWP 5327) 0x00007fa620df8482 in select () from /lib/libc.so.6
In many others runs it worked fine, bit I again hung with 50 threads cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0 cond_wait@ @GLIBC_ 2.3.2 () from /lib/libpthread .so.0
(gdb) info threads
66 Thread 0x421d6950 (LWP 5330) 0x00007fa6220ad2d9 in pthread_
65 Thread 0x429d7950 (LWP 5331) 0x00007fa6220ad2d9 in pthread_
64 Thread 0x431d8950 (LWP 5332) 0x00007fa6220ad2d9 in pthread_
63 Thread 0x439d9950 (LWP 5333) 0x00007fa6220ad2d9 in pthread_
62 Thread 0x441da950 (LWP 5334) 0x00007fa6220ad2d9 in pthread_
61 Thread 0x449db950 (LWP 5335) 0x00007fa6220ad2d9 in pthread_
60 Thread 0x451dc950 (LWP 5336) 0x00007fa6220ad2d9 in pthread_
59 Thread 0x459dd950 (LWP 5337) 0x00007fa6220ad2d9 in pthread_
58 Thread 0x461de950 (LWP 5338) 0x00007fa6220ad2d9 in pthread_
57 Thread 0x469df950 (LWP 5339) 0x00007fa6220ad2d9 in pthread_
56 Thread 0x4132a950 (LWP 5364) 0x00007fa620df8482 in select () from /lib/libc.so.6
55 Thread 0x471e0950 (LWP 5365) 0x00007fa6220ad2d9 in pthread_
54 Thread 0x479e1950 (LWP 5367) 0x00007fa6220ad2d9 in pthread_
53 Thread 0x47a22950 (LWP 5368) 0x00007fa6220b0e7b in sigwait () from /lib/libpthread
52 Thread 0x4136b950 (LWP 5406) 0x00007fa6220ad2d9 in pthread_
51 Thread 0x47a63950 (LWP 5408) 0x00007fa6220ad2d9 in pthread_
50 Thread 0x47aa4950 (LWP 5410) 0x00007fa6220ad2d9 in pthread_
49 Thread 0x47ae5950 (LWP 5414) 0x00007fa6220ad2d9 in pthread_
48 Thread 0x47b26950 (LWP 5415) 0x00007fa6220ad2d9 in pthread_
47 Thread 0x47b67950 (LWP 5416) 0x00007fa6220ad2d9 in pthread_
46 Thread 0x47ba8950 (LWP 5417) 0x00007fa6220ad2d9 in pthread_
45 Thread 0x47be9950 (LWP 5419) 0x00007fa6220ad2d9 in pthread_
44 Thread 0x47c2a950 (LWP 5422) 0x00007fa6220ad2d9 in pthread_
43 Thread 0x47c6b950 (LWP 5423) 0x00007fa6220ad2d9 in pthread_
42 Thread 0x47cac950 (LWP 5424) 0x00007fa6220ad2d9 in pthread_
41 Thread 0x47ced950 (LWP 5426) 0x00007fa6220ad2d9 in pthread_
40 Thread 0x47d2e950 (LWP 5428) 0x00007fa6220ad2d9 in pthread_
39 Thread 0x47d6f950 (LWP 5429) 0x00007fa6220ad2d9 in pthread_
38 Thread 0x47db0950 (LWP 5432) 0x00007fa6220ad2d9 in pthread_
37 Thread 0x47df1950 (LWP 5433) 0x00007fa6220ad2d9 in pthread_
36 Thread 0x47e32950 (LWP 5437) 0x00007fa6220ad2d9 in pthread_
35 Thread 0x47e73950 (LWP 5439) 0x00007fa6220ad2d9 in pthread_
34 Thread 0x47eb4950 (LWP 5443) 0x00007fa6220ad2d9 in pthread_
33 Thread 0x47ef5950 (LWP 5444) 0x00007fa6220ad2d9 in pthread_
32 Thread 0x47f36950 (LWP 5445) 0x00007fa6220ad2d9 in pthread_
31 Thread 0x47f77950 (LWP 5446) 0x00007fa6220ad2d9 in pthread_
30 Thread 0x47fb8950 (LWP 5448) 0x00007fa6220ad2d9 in pthread_
29 Thread 0x47ff9950 (LWP 5449) 0x00007fa6220ad2d9 in pthread_
28 Thread 0x4803a950 (LWP 5451) 0x00007fa6220ad2d9 in pthread_
27 Thread 0x4807b950 (LWP 5453) 0x00007fa6220ad2d9 in pthread_
26 Thread 0x480bc950 (LWP 5455) 0x00007fa6220ad2d9 in pthread_
25 Thread 0x480fd950 (LWP 5457) 0x00007fa6220ad2d9 in pthread_
24 Thread 0x4813e950 (LWP 5460) 0x00007fa6220ad2d9 in pthread_
23 Thread 0x4817f950 (LWP 5463) 0x00007fa6220ad2d9 in pthread_
22 Thread 0x481c0950 (LWP 5465) 0x00007fa6220ad2d9 in pthread_
21 Thread 0x48201950 (LWP 5466) 0x00007fa6220ad2d9 in pthread_
20 Thread 0x48242950 (LWP 5468) 0x00007fa6220ad2d9 in pthread_
19 Thread 0x48283950 (LWP 5469) 0x00007fa6220ad2d9 in pthread_
18 Thread 0x482c4950 (LWP 5471) 0x00007fa6220ad2d9 in pthread_
17 Thread 0x48305950 (LWP 5472) 0x00007fa6220ad2d9 in pthread_
16 Thread 0x48346950 (LWP 5477) 0x00007fa6220ad2d9 in pthread_
15 Thread 0x48387950 (LWP 5488) 0x00007fa6220ad2d9 in pthread_
14 Thread 0x483c8950 (LWP 5497) 0x00007fa6220ad2d9 in pthread_
13 Thread 0x48409950 (LWP 5498) 0x00007fa6220ad2d9 in pthread_
12 Thread 0x4844a950 (LWP 5499) 0x00007fa6220ad2d9 in pthread_
11 Thread 0x4848b950 (LWP 5501) 0x00007fa6220ad2d9 in pthread_
10 Thread 0x484cc950 (LWP 5502) 0x00007fa6220ad2d9 in pthread_
---Type <return> to continue, or q <return> to quit---
9 Thread 0x4850d950 (LWP 5504) 0x00007fa6220ad2d9 in pthread_
8 Thread 0x4854e950 (LWP 5505) 0x00007fa6220ad2d9 in pthread_
7 Thread 0x4858f950 (LWP 5506) 0x00007fa6220ad2d9 in pthread_
6 Thread 0x485d0950 (LWP 5507) 0x00007fa6220ad2d9 in pthread_
5 Thread 0x48611950 (LWP 5529) 0x00007fa6220ad2d9 in pthread_
4 Thread 0x413ac950 (LWP 5531) 0x00007fa6220ad2d9 in pthread_
3 Thread 0x413ed950 (LWP 5532) 0x00007fa6220ad2d9 in pthread_
2 Thread 0x4142e950 (LWP 8568) 0x00007fa6220ad2d9 in pthread_
1 Thread 0x7fa6224d06f0 (LWP 5327) 0x00007fa620df8482 in select () from /lib/libc.so.6