* further pthread foo
@ 2011-03-18 22:26 Andy Wingo
[not found] ` <m339mkxdyh.fsf-CaTCM8lwFkgB9AHHLWeGtNQXobZC6xk2@public.gmane.org>
0 siblings, 1 reply; 3+ messages in thread
From: Andy Wingo @ 2011-03-18 22:26 UTC (permalink / raw)
To: gc; +Cc: bug-guile
Hello again!
Continuing on the same topic as my previous mail, which you may read
here:
http://thread.gmane.org/gmane.lisp.guile.bugs/5340
I modified the program to do a `scm_init_guile ()' before creating any
threads. This initializes libgc from the main thread, so all should be
well. But then I run into a problem:
(gdb) r
Starting program: /tmp/many_threads
[Thread debugging using libthread_db enabled]
0: create[New Thread 0x7ffff740b700 (LWP 23030)]
join
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff740b700 (LWP 23030)]
0x00007ffff7a09200 in GC_malloc (bytes=16) at thread_local_alloc.c:161
161 GC_FAST_MALLOC_GRANS(result, granules, tiny_fl, DIRECT_GRANULES,
(gdb) thr apply all bt
Thread 2 (Thread 0x7ffff740b700 (LWP 23030)):
#0 0x00007ffff7a09200 in GC_malloc (bytes=16) at thread_local_alloc.c:161
#1 0x00007ffff7d1208e in scm_cell (x=<value optimized out>, y=<value optimized out>) at ../libguile/inline.h:124
#2 scm_cons (x=<value optimized out>, y=<value optimized out>) at pairs.c:77
#3 0x00007ffff7cd05b7 in scm_i_with_continuation_barrier (body=0x7ffff7cd03a0 <c_body>, body_data=0x7ffff740adb0,
handler=0x7ffff7cd03c0 <c_handler>, handler_data=0x7ffff740adb0, pre_unwind_handler=<value optimized out>,
pre_unwind_handler_data=<value optimized out>) at continuations.c:444
#4 0x00007ffff7cd0690 in scm_c_with_continuation_barrier (func=<value optimized out>, data=<value optimized out>)
at continuations.c:491
#5 0x00007ffff7a0982f in GC_call_with_gc_active (fn=0x7ffff7d48740 <with_guile_trampoline>, client_data=0x7ffff740ae20)
at pthread_support.c:1127
#6 0x00007ffff7d48aed in with_gc_active (func=0x7ffff7d488e0 <do_thread_exit>, data=0x949600, parent=<value optimized out>)
at threads.c:97
#7 scm_i_with_guile_and_parent (func=0x7ffff7d488e0 <do_thread_exit>, data=0x949600, parent=<value optimized out>)
at threads.c:826
#8 0x00007ffff7d48bc7 in do_thread_exit_trampoline (sb=<value optimized out>, v=0x949600) at threads.c:549
#9 0x00007ffff7a03525 in GC_call_with_stack_base (fn=<value optimized out>, arg=<value optimized out>) at misc.c:1493
#10 0x00007ffff7d48867 in on_thread_exit (v=0x949600) at threads.c:580
#11 0x0000003fc86077f9 in __nptl_deallocate_tsd (arg=0x7ffff740b700) at pthread_create.c:154
#12 start_thread (arg=0x7ffff740b700) at pthread_create.c:308
#13 0x0000003fc7ee098d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:115
Thread 1 (Thread 0x7ffff76ce700 (LWP 23027)):
#0 0x0000003fc8607fbd in pthread_join (threadid=140737341601536, thread_return=0x7fffffffe018) at pthread_join.c:89
#1 0x00007ffff7a09e47 in GC_pthread_join (thread=140737341601536, retval=0x7fffffffe018) at pthread_support.c:1219
#2 0x00000000004008e7 in main () at many_threads.c:31
What is happening is that I have registered a pthread_key cleanup
handler, and I need to call a Guile function in that handler. But quite
possibly, libgc has already torn down this thread. So I trampoline
through a GC_call_with_stack_base, then register the current thread. If
that returns GC_SUCCESS, later I unregister it. In between there is the
scm_i_with_guile_and_parent call you see at frame #7.
However as you see, there is unhappiness there. I don't know what
exactly is causing the segfault, but here's a disassembly:
(gdb) disassemble $pc
Dump of assembler code for function GC_malloc:
0x00007ffff7a09180 <+0>: mov %rbx,-0x30(%rsp)
0x00007ffff7a09185 <+5>: mov %r13,-0x18(%rsp)
0x00007ffff7a0918a <+10>: mov %rdi,%rbx
0x00007ffff7a0918d <+13>: mov %rbp,-0x28(%rsp)
0x00007ffff7a09192 <+18>: mov %r12,-0x20(%rsp)
0x00007ffff7a09197 <+23>: mov %r14,-0x10(%rsp)
0x00007ffff7a0919c <+28>: mov %r15,-0x8(%rsp)
0x00007ffff7a091a1 <+33>: sub $0x48,%rsp
0x00007ffff7a091a5 <+37>: mov 0x20a104(%rip),%rax # 0x7ffff7c132b0
0x00007ffff7a091ac <+44>: mov (%rax),%r12d
0x00007ffff7a091af <+47>: data32 lea 0x20a3e9(%rip),%rdi # 0x7ffff7c135a0
0x00007ffff7a091b7 <+55>: data32 data32 callq 0x7ffff79f6da0 <__tls_get_addr@plt>
0x00007ffff7a091bf <+63>: mov (%rax),%r13
0x00007ffff7a091c2 <+66>: test %r13,%r13
0x00007ffff7a091c5 <+69>: je 0x7ffff7a0923f <GC_malloc+191>
0x00007ffff7a091c7 <+71>: add $0xf,%r12d
0x00007ffff7a091cb <+75>: movslq %r12d,%r12
0x00007ffff7a091ce <+78>: lea (%rbx,%r12,1),%r12
0x00007ffff7a091d2 <+82>: shr $0x4,%r12
0x00007ffff7a091d6 <+86>: cmp $0x18,%r12
0x00007ffff7a091da <+90>: ja 0x7ffff7a0923f <GC_malloc+191>
0x00007ffff7a091dc <+92>: lea 0x18(%r12),%r14
0x00007ffff7a091e1 <+97>: mov %r12,%rbp
0x00007ffff7a091e4 <+100>: mov $0x10,%r15d
0x00007ffff7a091ea <+106>: shl $0x4,%rbp
0x00007ffff7a091ee <+110>: mov 0x8(%r13,%r14,8),%rax
0x00007ffff7a091f3 <+115>: lea 0x8(%r13,%r14,8),%rcx
0x00007ffff7a091f8 <+120>: cmp $0x11a,%rax
0x00007ffff7a091fe <+126>: jbe 0x7ffff7a09269 <GC_malloc+233>
=> 0x00007ffff7a09200 <+128>: mov (%rax),%rdx
0x00007ffff7a09203 <+131>: mov %rdx,0x8(%r13,%r14,8)
0x00007ffff7a09208 <+136>: prefetcht0 (%rdx)
0x00007ffff7a0920b <+139>: movq $0x0,(%rax)
0x00007ffff7a09212 <+146>: mov 0x18(%rsp),%rbx
0x00007ffff7a09217 <+151>: mov 0x20(%rsp),%rbp
0x00007ffff7a0921c <+156>: mov 0x28(%rsp),%r12
0x00007ffff7a09221 <+161>: mov 0x30(%rsp),%r13
0x00007ffff7a09226 <+166>: mov 0x38(%rsp),%r14
0x00007ffff7a0922b <+171>: mov 0x40(%rsp),%r15
0x00007ffff7a09230 <+176>: add $0x48,%rsp
0x00007ffff7a09234 <+180>: retq
(gdb) info registers
rax 0x1000 4096
rbx 0x10 16
rcx 0x6b1650 7018064
rdx 0x2 2
rsi 0x0 0
rdi 0x6027e0 6301664
rbp 0x10 0x10
rsp 0x7ffff740acc0 0x7ffff740acc0
r8 0x7ffff7d490b0 140737351291056
r9 0x0 0
r10 0x7ffff740aba0 140737341598624
r11 0x7ffff7a097c0 140737347884992
r12 0x1 1
r13 0x6b1580 7017856
r14 0x19 25
r15 0x10 16
rip 0x7ffff7a09200 0x7ffff7a09200 <GC_malloc+128>
eflags 0x10212 [ AF IF RF ]
cs 0x33 51
ss 0x2b 43
ds 0x0 0
es 0x0 0
fs 0x0 0
gs 0x0 0
This is with current CVS.
Regards,
Andy
--
http://wingolog.org/
^ permalink raw reply [flat|nested] 3+ messages in thread[parent not found: <m339mkxdyh.fsf-CaTCM8lwFkgB9AHHLWeGtNQXobZC6xk2@public.gmane.org>]
* Re: further pthread foo [not found] ` <m339mkxdyh.fsf-CaTCM8lwFkgB9AHHLWeGtNQXobZC6xk2@public.gmane.org> @ 2011-03-19 21:25 ` Ivan Maidanski 2011-03-19 23:34 ` [Gc] " Andy Wingo 0 siblings, 1 reply; 3+ messages in thread From: Ivan Maidanski @ 2011-03-19 21:25 UTC (permalink / raw) To: Andy Wingo; +Cc: bug-guile, gc-V9/bV5choksm30D7ZfaTJw Hi Andy, Try to compile libgc with -DGC_ASSERTIONS but without -DTHREAD_LOCAL_ALLOC -DPARALLEL_MARK. I cannot help you more in figuring out what's the problem (due to lack of time). Probably someone else could help you more... BTW. Why do you use GC_call_with_gc_active()? It should be no-op in your case - the thread is stopped and scanned after you call GC_register_my_thread. (GC_call_with_gc_active is used primarily inside GC_do_blocking calls). Fri, 18 Mar 2011 23:26:30 +0100 Andy Wingo <wingo-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>: > Hello again! > > Continuing on the same topic as my previous mail, which you may read > here: > > http://thread.gmane.org/gmane.lisp.guile.bugs/5340 > > I modified the program to do a `scm_init_guile ()' before creating any > threads. This initializes libgc from the main thread, so all should be > well. But then I run into a problem: > > (gdb) r > Starting program: /tmp/many_threads > [Thread debugging using libthread_db enabled] > 0: create[New Thread 0x7ffff740b700 (LWP 23030)] > join > Program received signal SIGSEGV, Segmentation fault. > [Switching to Thread 0x7ffff740b700 (LWP 23030)] > 0x00007ffff7a09200 in GC_malloc (bytes=16) at thread_local_alloc.c:161 > 161 GC_FAST_MALLOC_GRANS(result, granules, tiny_fl, DIRECT_GRANULES, > (gdb) thr apply all bt > Thread 2 (Thread 0x7ffff740b700 (LWP 23030)): > #0 0x00007ffff7a09200 in GC_malloc (bytes=16) at thread_local_alloc.c:161 > #1 0x00007ffff7d1208e in scm_cell (x=<value optimized out>, y=<value > optimized out>) at ../libguile/inline.h:124 > #2 scm_cons (x=<value optimized out>, y=<value optimized out>) at pairs.c:77 > #3 0x00007ffff7cd05b7 in scm_i_with_continuation_barrier (body=0x7ffff7cd03a0 > <c_body>, body_data=0x7ffff740adb0, > handler=0x7ffff7cd03c0 <c_handler>, handler_data=0x7ffff740adb0, > pre_unwind_handler=<value optimized out>, > pre_unwind_handler_data=<value optimized out>) at continuations.c:444 > #4 0x00007ffff7cd0690 in scm_c_with_continuation_barrier (func=<value > optimized out>, data=<value optimized out>) > at continuations.c:491 > #5 0x00007ffff7a0982f in GC_call_with_gc_active (fn=0x7ffff7d48740 > <with_guile_trampoline>, client_data=0x7ffff740ae20) > at pthread_support.c:1127 > #6 0x00007ffff7d48aed in with_gc_active (func=0x7ffff7d488e0 > <do_thread_exit>, data=0x949600, parent=<value optimized out>) > at threads.c:97 > #7 scm_i_with_guile_and_parent (func=0x7ffff7d488e0 <do_thread_exit>, > data=0x949600, parent=<value optimized out>) > at threads.c:826 > #8 0x00007ffff7d48bc7 in do_thread_exit_trampoline (sb=<value optimized out>, > v=0x949600) at threads.c:549 > #9 0x00007ffff7a03525 in GC_call_with_stack_base (fn=<value optimized out>, > arg=<value optimized out>) at misc.c:1493 > #10 0x00007ffff7d48867 in on_thread_exit (v=0x949600) at threads.c:580 > #11 0x0000003fc86077f9 in __nptl_deallocate_tsd (arg=0x7ffff740b700) at > pthread_create.c:154 > #12 start_thread (arg=0x7ffff740b700) at pthread_create.c:308 > #13 0x0000003fc7ee098d in clone () at > ../sysdeps/unix/sysv/linux/x86_64/clone.S:115 > > Thread 1 (Thread 0x7ffff76ce700 (LWP 23027)): > #0 0x0000003fc8607fbd in pthread_join (threadid=140737341601536, > thread_return=0x7fffffffe018) at pthread_join.c:89 > #1 0x00007ffff7a09e47 in GC_pthread_join (thread=140737341601536, > retval=0x7fffffffe018) at pthread_support.c:1219 > #2 0x00000000004008e7 in main () at many_threads.c:31 > > What is happening is that I have registered a pthread_key cleanup > handler, and I need to call a Guile function in that handler. But quite > possibly, libgc has already torn down this thread. So I trampoline > through a GC_call_with_stack_base, then register the current thread. If > that returns GC_SUCCESS, later I unregister it. In between there is the > scm_i_with_guile_and_parent call you see at frame #7. > > However as you see, there is unhappiness there. I don't know what > exactly is causing the segfault, but here's a disassembly: > > (gdb) disassemble $pc > Dump of assembler code for function GC_malloc: > 0x00007ffff7a09180 <+0>: mov %rbx,-0x30(%rsp) > 0x00007ffff7a09185 <+5>: mov %r13,-0x18(%rsp) > 0x00007ffff7a0918a <+10>: mov %rdi,%rbx > 0x00007ffff7a0918d <+13>: mov %rbp,-0x28(%rsp) > 0x00007ffff7a09192 <+18>: mov %r12,-0x20(%rsp) > 0x00007ffff7a09197 <+23>: mov %r14,-0x10(%rsp) > 0x00007ffff7a0919c <+28>: mov %r15,-0x8(%rsp) > 0x00007ffff7a091a1 <+33>: sub $0x48,%rsp > 0x00007ffff7a091a5 <+37>: mov 0x20a104(%rip),%rax # 0x7ffff7c132b0 > 0x00007ffff7a091ac <+44>: mov (%rax),%r12d > 0x00007ffff7a091af <+47>: data32 lea 0x20a3e9(%rip),%rdi # > 0x7ffff7c135a0 > 0x00007ffff7a091b7 <+55>: data32 data32 callq 0x7ffff79f6da0 > <__tls_get_addr@plt> > 0x00007ffff7a091bf <+63>: mov (%rax),%r13 > 0x00007ffff7a091c2 <+66>: test %r13,%r13 > 0x00007ffff7a091c5 <+69>: je 0x7ffff7a0923f <GC_malloc+191> > 0x00007ffff7a091c7 <+71>: add $0xf,%r12d > 0x00007ffff7a091cb <+75>: movslq %r12d,%r12 > 0x00007ffff7a091ce <+78>: lea (%rbx,%r12,1),%r12 > 0x00007ffff7a091d2 <+82>: shr $0x4,%r12 > 0x00007ffff7a091d6 <+86>: cmp $0x18,%r12 > 0x00007ffff7a091da <+90>: ja 0x7ffff7a0923f <GC_malloc+191> > 0x00007ffff7a091dc <+92>: lea 0x18(%r12),%r14 > 0x00007ffff7a091e1 <+97>: mov %r12,%rbp > 0x00007ffff7a091e4 <+100>: mov $0x10,%r15d > 0x00007ffff7a091ea <+106>: shl $0x4,%rbp > 0x00007ffff7a091ee <+110>: mov 0x8(%r13,%r14,8),%rax > 0x00007ffff7a091f3 <+115>: lea 0x8(%r13,%r14,8),%rcx > 0x00007ffff7a091f8 <+120>: cmp $0x11a,%rax > 0x00007ffff7a091fe <+126>: jbe 0x7ffff7a09269 <GC_malloc+233> > => 0x00007ffff7a09200 <+128>: mov (%rax),%rdx > 0x00007ffff7a09203 <+131>: mov %rdx,0x8(%r13,%r14,8) > 0x00007ffff7a09208 <+136>: prefetcht0 (%rdx) > 0x00007ffff7a0920b <+139>: movq $0x0,(%rax) > 0x00007ffff7a09212 <+146>: mov 0x18(%rsp),%rbx > 0x00007ffff7a09217 <+151>: mov 0x20(%rsp),%rbp > 0x00007ffff7a0921c <+156>: mov 0x28(%rsp),%r12 > 0x00007ffff7a09221 <+161>: mov 0x30(%rsp),%r13 > 0x00007ffff7a09226 <+166>: mov 0x38(%rsp),%r14 > 0x00007ffff7a0922b <+171>: mov 0x40(%rsp),%r15 > 0x00007ffff7a09230 <+176>: add $0x48,%rsp > 0x00007ffff7a09234 <+180>: retq > > (gdb) info registers > rax 0x1000 4096 > rbx 0x10 16 > rcx 0x6b1650 7018064 > rdx 0x2 2 > rsi 0x0 0 > rdi 0x6027e0 6301664 > rbp 0x10 0x10 > rsp 0x7ffff740acc0 0x7ffff740acc0 > r8 0x7ffff7d490b0 140737351291056 > r9 0x0 0 > r10 0x7ffff740aba0 140737341598624 > r11 0x7ffff7a097c0 140737347884992 > r12 0x1 1 > r13 0x6b1580 7017856 > r14 0x19 25 > r15 0x10 16 > rip 0x7ffff7a09200 0x7ffff7a09200 <GC_malloc+128> > eflags 0x10212 [ AF IF RF ] > cs 0x33 51 > ss 0x2b 43 > ds 0x0 0 > es 0x0 0 > fs 0x0 0 > gs 0x0 0 > > This is with current CVS. > > Regards, > > Andy > -- > http://wingolog.org/ > _______________________________________________ > Gc mailing list > Gc-V9/bV5choksm30D7ZfaTJw@public.gmane.org > http://www.hpl.hp.com/hosted/linux/mail-archives/gc/ ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Gc] further pthread foo 2011-03-19 21:25 ` Ivan Maidanski @ 2011-03-19 23:34 ` Andy Wingo 0 siblings, 0 replies; 3+ messages in thread From: Andy Wingo @ 2011-03-19 23:34 UTC (permalink / raw) To: Ivan Maidanski; +Cc: bug-guile, gc Hi Ivan, On Sat 19 Mar 2011 22:25, Ivan Maidanski <ivmai@mail.ru> writes: > Try to compile libgc with -DGC_ASSERTIONS but without > -DTHREAD_LOCAL_ALLOC -DPARALLEL_MARK. OK, will do. Thanks for the suggestion, and sorry for the burden. You must get the worst bugs! > BTW. Why do you use GC_call_with_gc_active()? It should be no-op in your > case - the thread is stopped and scanned after you call > GC_register_my_thread. (GC_call_with_gc_active is used primarily inside > GC_do_blocking calls). We have scm_with_guile and scm_without_guile, which invoke a procedure in and out of Guile mode. scm_with_guile nests as you would think it would, and scm_without_guile can only be called in Guile mode. If a thread is not in Guile mode, it shouldn't be active for GC purposes -- shouldn't be in the thread set to stop -- so it goes through a do_blocking. scm_with_guile therefore goes through a GC_call_with_gc_active, even in the case that it's not in the extent of a GC_do_blocking context call. So yes, it's a no-op, and harmles in this case. Regards, Andy -- http://wingolog.org/ ^ permalink raw reply [flat|nested] 3+ messages in thread
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2011-03-18 22:26 further pthread foo Andy Wingo
[not found] ` <m339mkxdyh.fsf-CaTCM8lwFkgB9AHHLWeGtNQXobZC6xk2@public.gmane.org>
2011-03-19 21:25 ` Ivan Maidanski
2011-03-19 23:34 ` [Gc] " Andy Wingo
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