Re: crashing socket tests

[Vladimir T. <vtz...@gm...>]

Hi Bruno,

On Sat, May 27, 2017 at 12:14 AM, Vladimir Tzankov <vtz...@gm...>
wrote:

> There was no GC run since the startup (double checked it) so it should not
>> be GC safety issue.
>>
>
> Actually I was wrong in my double checking :(.
> This happens after the first GC. Would classify it as GC safety issue now.
>

I see you've added OLD_GC to revert to pre-MT GC. While adding MT stuff I
tried hard to keep everything "as is" in single thread builds.

Back to the issue - I experience the same problem with OLD_GC
enabled. After adding some debug logging (see the diff below) I observe
strm_encoding of the stream object is not getting updated during the GC.
This is SINGLEMAP_MEMORY with OLD_GC.

vtz@debian:~/clisp/src$ hg diff .
diff -r d573e8e54c34 src/spvw_garcol_old.d
--- a/src/spvw_garcol_old.d Fri May 26 19:24:49 2017 +0200
+++ b/src/spvw_garcol_old.d Thu May 25 06:00:37 2017 +0300
@@ -1493,6 +1493,7 @@
 /* perform normal Garbage Collection: */
 local void gar_col_normal (void)
 {
+  printf("PERFORM GC: %d\n", gc_count);
   var uintM gcstart_space;      /* occupied memory at GC-start */
   var uintM gcend_space;        /* occupied memory at GC-end */
   var object all_weakpointers;  /* list of active Weak-pointers */
diff -r d573e8e54c34 src/stream.d
--- a/src/stream.d Fri May 26 19:24:49 2017 +0200
+++ b/src/stream.d Thu May 25 06:00:37 2017 +0300
@@ -6651,8 +6651,10 @@
     var uintL available = endvalid - BufferedStream_index(stream);
     var const uintB* bptr = bufferptr;
     var chart* cptr = &c;
+    printf("BEFORE: STREAM: %p, ENCODING: %p\n", stream, encoding);
     Encoding_mbstowcs(encoding)
       (encoding,stream,&bptr,bufferptr+available,&cptr,&c+1);
+    printf("AFTER: STREAM: %p, ENCODING: %p\n", stream, encoding);
     if (cptr == &c+1) {
       var uintL n = bptr-bufferptr;
       /* increment index and position */


And here is the output in gdb:

[1]> (describe nil)
...
BEFORE: STREAM: 0xb0000005ac0, ENCODING: 0xc000001a280
AFTER: STREAM: 0xb0000005ac0, ENCODING: 0xc000001a280
... /* VTZ: plenty of the above */
BEFORE: STREAM: 0xb0000005ac0, ENCODING: 0xc000001a280
AFTER: STREAM: 0xb0000005ac0, ENCODING: 0xc000001a280
PERFORM GC: 0 /*VTZ: first GC run */
BEFORE: STREAM: 0xb0000001780, ENCODING: 0xc000001a280

*** - handle_fault error2 ! address = 0xc000001a2b8 not in
[0xc0000000000,0xc00000179f0) !
Breakpoint 1, sigsegv_handler_failed (address=address@entry=0xc000001a2b8)
at ../src/spvw_sigsegv.d:64
64  fputc('\n',stderr);
(gdb) p /x mem.heaps[0x0b]
$1 = {pages = {start = 0xb0000000000, end = 0xb0000001a60, gcpriv =
{firstmarked = 0xb0000001000, l = 0xb0000001000, d = 0xb0000001000, next =
0xb0000001000}},
  heap_limit = 0xb0000002000, heap_hardlimit = 0xc0000000000,
heap_gen0_start = 0xb0000000000, heap_gen0_end = 0xb0000000d80,
heap_gen1_start = 0xb0000001000,
  physpages = 0x83aff0}
(gdb) p /x mem.heaps[0x0c]
$2 = {pages = {start = 0xc0000000000, end = 0xc00000183a8, gcpriv =
{firstmarked = 0xc0000018000, l = 0xc0000018000, d = 0xc0000018000, next =
0xc0000018000}},
  heap_limit = 0xc0000019000, heap_hardlimit = 0xd0000000000,
heap_gen0_start = 0xc0000000000, heap_gen0_end = 0xc00000179f0,
heap_gen1_start = 0xc0000018000,
  physpages = 0x83ca10}

The stream object has been moved due to compaction but strm_encoding has
either not moved (unlikely - its heap has shrunk) or has not been updated.