[Gc] Fwd: [bdwgc] Race conditions between thread termination and garbage collection (#86)

[Ivan Maidanski]

-------- Forwarded message --------
From: Daniel Mendler <***@github.com>
CC: ivmai/bdwgc <***@noreply.github.com>
Date: Sat, 09 Jan 2016, 16:46 +03:00
Subj: [bdwgc] Race conditions between thread termination and garbage collection (#86)
This was discussed before, but I don't know if it was resolved:  http://www.hpl.hp.com/hosted/linux/mail-archives/gc/2010-March/003793.html
I use github master.
(gdb) info threads
  Id   Target Id         Frame
  11   Thread 0x7f7dfd962700 (LWP 2022) 0x00007f7e04dcd482 in do_sigsuspend (set=0x7f7e059db240 <suspend_handler_mask>) at ../sysdeps/unix/sysv/linux/sigsuspend.c:31
  10   Thread 0x7f7dfe163700 (LWP 2021) 0x00007f7e04dcd482 in do_sigsuspend (set=0x7f7e059db240 <suspend_handler_mask>) at ../sysdeps/unix/sysv/linux/sigsuspend.c:31
  9    Thread 0x7f7dfe964700 (LWP 2020) 0x00007f7e04dcd482 in do_sigsuspend (set=0x7f7e059db240 <suspend_handler_mask>) at ../sysdeps/unix/sysv/linux/sigsuspend.c:31
  8    Thread 0x7f7dff165700 (LWP 2019) 0x00007f7e04dcd482 in do_sigsuspend (set=0x7f7e059db240 <suspend_handler_mask>) at ../sysdeps/unix/sysv/linux/sigsuspend.c:31
  7    Thread 0x7f7dff966700 (LWP 2018) 0x00007f7e04dcd482 in do_sigsuspend (set=0x7f7e059db240 <suspend_handler_mask>) at ../sysdeps/unix/sysv/linux/sigsuspend.c:31
  6    Thread 0x7f7e00167700 (LWP 2017) 0x00007f7e04dcd482 in do_sigsuspend (set=0x7f7e059db240 <suspend_handler_mask>) at ../sysdeps/unix/sysv/linux/sigsuspend.c:31
  5    Thread 0x7f7e00968700 (LWP 2016) 0x00007f7e04dcd482 in do_sigsuspend (set=0x7f7e059db240 <suspend_handler_mask>) at ../sysdeps/unix/sysv/linux/sigsuspend.c:31
  4    Thread 0x7f7e01169700 (LWP 2015) sem_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S:85
  3    Thread 0x7f7e0216b700 (LWP 2013) __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
  2    Thread 0x7f7e04970700 (LWP 2008) pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
* 1    Thread 0x7f7e05c05b40 (LWP 2007) 0x00007f7e04dcd482 in do_sigsuspend (set=0x7f7e059db240 <suspend_handler_mask>) at ../sysdeps/unix/sysv/linux/sigsuspend.c:31
It seems that threads 2, 3, 4 are dead locked.
(gdb) thread 4
[Switching to thread 4 (Thread 0x7f7e01169700 (LWP 2015))]
#0  sem_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S:85
85  ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S: No such file or directory.
(gdb) bt
#0  sem_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_wait.S:85
#1  0x00007f7e057bcf82 in GC_stop_world () at pthread_stop_world.c:662
#2  0x00007f7e057a913e in GC_stopped_mark (stop_func=***@entry=0x7f7e057a8c40 <GC_never_stop_func>) at alloc.c:646
#3  0x00007f7e057a9c99 in GC_try_to_collect_inner (stop_func=0x7f7e057a8c40 <GC_never_stop_func>) at alloc.c:486
#4  0x00007f7e057a9f0a in GC_try_to_collect_general (stop_func=***@entry=0x0, force_unmap=***@entry=0) at alloc.c:1065
#5  0x00007f7e057a9fdd in GC_gcollect () at alloc.c:1089
(gdb) thread 3
[Switching to thread 3 (Thread 0x7f7e0216b700 (LWP 2013))]
#0  __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
135 in ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S
(gdb) bt
#0  __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
#1  0x00007f7e055864b9 in _L_lock_909 () from /lib/x86_64-linux-gnu/libpthread.so.0
#2  0x00007f7e055862e0 in __GI___pthread_mutex_lock (mutex=0x7f7e059daca0 <GC_allocate_ml>) at ../nptl/pthread_mutex_lock.c:79
#3  0x00007f7e057bbed5 in GC_thread_exit_proc (arg=***@entry=0x2662c00) at pthread_support.c:1409
#4  0x00007f7e057bacad in GC_inner_start_routine (sb=<error reading variable: value has been optimized out>, arg=<error reading variable: value has been optimized out>) at pthread_start.c:63
#5  0x00007f7e057b5a42 in GC_call_with_stack_base (fn=<optimized out>, arg=<optimized out>) at misc.c:1925
#6  0x00007f7e055840a4 in start_thread (arg=0x7f7e0216b700) at pthread_create.c:309
#7  0x00007f7e04e7e04d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
(gdb) thread 2
[Switching to thread 2 (Thread 0x7f7e04970700 (LWP 2008))]
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
185 ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S: No such file or directory.
(gdb) bt
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f7e057bc8f7 in GC_wait_marker () at pthread_support.c:2121
#2  0x00007f7e057b2cea in GC_help_marker (my_mark_no=***@entry=30) at mark.c:1186
#3  0x00007f7e057bc8cc in GC_mark_thread (id=<optimized out>) at pthread_support.c:380
#4  0x00007f7e055840a4 in start_thread (arg=0x7f7e04970700) at pthread_create.c:309
#5  0x00007f7e04e7e04d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
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