Issue #4721 has been reported by Sascha Peilicke.

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Bug #4721: Segfault near rb_thread_check, probably a timing issue.
http://redmine.ruby-lang.org/issues/4721

Author: Sascha Peilicke
Status: Open
Priority: Normal
Assignee: 
Category: core
Target version: 
ruby -v: ruby 1.8.7 (2011-02-18 patchlevel 334) [x86_64-linux]


Was triggered by adding a 'debugger' statement (for ruby-debug) into Rails code and pressing 'c' to continue after breakpoint.

Backtrace (see also attached core file):

Program terminated with signal 11, Segmentation fault.
#0  ___vsnprintf_chk (s=0x7fffe4705060 "", maxlen=8192, flags=1, slen=8192, 
    format=0x7f78850e8bb8 "wrong argument type %s (expected Thread)", args=0x7fffe4705048)
    at vsnprintf_chk.c:44
44      vsnprintf_chk.c: No such file or directory.
        in vsnprintf_chk.c
(gdb) bt
#0  ___vsnprintf_chk (s=0x7fffe4705060 "", maxlen=8192, flags=1, slen=8192, 
    format=0x7f78850e8bb8 "wrong argument type %s (expected Thread)", args=0x7fffe4705048)
    at vsnprintf_chk.c:44
#1  0x00007f7885066a0d in vsnprintf (__ap=0x7fffe4705048, __fmt=<optimized out>, __n=8192, 
    __s=0x7fffe4705060 "") at /usr/include/bits/stdio2.h:78
#2  rb_raise (exc=140155609583120, fmt=<optimized out>) at error.c:1054
#3  0x00007f788506b9ea in rb_thread_check (data=<optimized out>) at eval.c:10582
#4  rb_thread_check (data=<optimized out>) at eval.c:10578
#5  0x00007f788506fa2b in rb_thread_wakeup_alive (thread=140155516998120) at eval.c:11729
#6  0x00007f788506fa79 in rb_thread_wakeup (thread=140155516998120) at eval.c:11720
#7  0x00007f7885080d39 in rb_thread_run (thread=140155516998120) at eval.c:11763
#8  0x00007f787ee7c114 in debug_event_hook (event=<optimized out>, node=<optimized out>, 
    self=140155609583120, mid=<optimized out>, klass=<optimized out>) at ruby_debug.c:972
#9  0x00007f78850729ce in rb_call0 (klass=140155609614840, recv=140155609583120, id=3361, 
    oid=<optimized out>, argc=1, argv=0x7fffe4707520, body=0x7f788552e4f0, flags=0) at eval.c:5915
#10 0x00007f78850741cf in rb_call (klass=140155609614840, recv=140155609583120, mid=3361, argc=1, 
    argv=0x7fffe4707520, scope=1, self=<optimized out>) at eval.c:6176
#11 0x00007f7885074915 in vafuncall (recv=<optimized out>, mid=<optimized out>, n=<optimized out>, 
    ar=<optimized out>) at eval.c:6253
#12 0x00007f7885074bb4 in rb_funcall (recv=<optimized out>, mid=<optimized out>, n=<optimized out>)
    at eval.c:6270


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