From: shyouhei@...
Date: 2019-03-11T00:34:55+00:00
Subject: [ruby-core:91738] [Ruby trunk Bug#15651] infinite loop in int_pow

Issue #15651 has been updated by shyouhei (Shyouhei Urabe).


```
zsh % gdb --args ./miniruby -ve '[1].repeated_permutation(1).size'
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Reading symbols from ./miniruby...done.
(gdb) run
Starting program: /home/shyouhei/data/build/ruby@gcc-8/trunk@git/miniruby -ve \[1\].repeated_permutation\(1\).size
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
ruby 2.7.0dev (2019-03-05 trunk 67168) [x86_64-linux]
^C
Program received signal SIGINT, Interrupt.
int_pow (x=1, y=0) at /trunk/numeric.c:3999
3999                if (!FIT_SQRT_LONG(x)) {
(gdb) bt
#0  int_pow (x=1, y=0) at /trunk/numeric.c:3999
#1  0x000055555579000c in vm_call_cfunc_with_frame (ci=0x555555bd2c80, cc=<optimized out>, calling=0x555555ae68c0, reg_cfp=0x7ffff7fd3fa0, ec=0x555555ab54f8) at /trunk/vm_insnhelper.c:2006
#2  vm_call_cfunc () at /trunk/vm_insnhelper.c:2022
#3  0x0000555555794759 in vm_call_method_each_type.part () at /trunk/vm_insnhelper.c:2344
#4  0x0000555555794d12 in vm_call_method_each_type (cc=<optimized out>, ci=<optimized out>, calling=<optimized out>, cfp=<optimized out>, ec=<optimized out>) at /trunk/vm_insnhelper.c:2468
#5  vm_call_method (cc=<optimized out>, ci=<optimized out>, calling=<optimized out>, cfp=<optimized out>, ec=<optimized out>) at /trunk/vm_insnhelper.c:2496
#6  vm_call_method (ec=0x555555ab54f8, cfp=0x7ffff7fd3fa0, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at /trunk/vm_insnhelper.c:2463
#7  0x000055555579b580 in vm_sendish (method_explorer=<optimized out>, block_handler=<optimized out>, cc=<optimized out>, ci=<optimized out>, reg_cfp=<optimized out>, ec=<optimized out>)
    at /trunk/vm_insnhelper.c:3350
#8  vm_exec_core () at ../../../src/trunk/insns.def:782
#9  0x00005555557929c6 in rb_vm_exec () at /trunk/vm.c:1897
#10 0x00005555557a40ea in rb_iseq_eval_main (iseq=<optimized out>) at /trunk/vm.c:2156
#11 0x00005555556087cf in ruby_exec_internal (n=0x555555ad6b00) at /trunk/eval.c:261
#12 0x000055555560c74b in ruby_exec_node (n=<optimized out>) at /trunk/eval.c:325
#13 ruby_run_node (n=<optimized out>) at /trunk/eval.c:317
#14 0x000055555557b0ef in main (argc=<optimized out>, argv=<optimized out>) at /trunk/main.c:42
(gdb)
```

----------------------------------------
Bug #15651: infinite loop in int_pow
https://bugs.ruby-lang.org/issues/15651#change-77014

* Author: pb (pumbur _)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 
* Backport: 2.4: UNKNOWN, 2.5: UNKNOWN, 2.6: UNKNOWN
----------------------------------------
`[1].repeated_permutation(1).size` goes into infinite loop.



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