# Valgrind set\_trace\_func

**URL:** <https://www.ruby-forum.com/t/valgrind-set-trace-func/115263>\
**Category:** Development\
**Created:** [September 22, 2007, 9:12pm UTC](https://www.ruby-forum.com/t/valgrind-set-trace-func/115263 "2007-09-22T21:12:01Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [September 22, 2007, 9:12pm UTC](https://www.ruby-forum.com/t/valgrind-set-trace-func/115263/1 "2007-09-22T21:12:01Z")

</div>

e$B0J2\<$N$h$&$K$9$k$He(B Invalid read of size 4 e$B$H$J$j$^$9!#e(B

% valgrind ./ruby -ve ‘set\_trace\_func(proc {})’  
==13641== Memcheck, a memory error detector.  
==13641== Copyright © 2002-2006, and GNU GPL’d, by Julian Seward et  
al.  
==13641== Using LibVEX rev 1658, a library for dynamic binary  
translation.  
==13641== Copyright © 2004-2006, and GNU GPL’d, by OpenWorks LLP.  
==13641== Using valgrind-3.2.1-Debian, a dynamic binary instrumentation  
framework.  
==13641== Copyright © 2000-2006, and GNU GPL’d, by Julian Seward et  
al.  
==13641== For more details, rerun with: -v  
==13641==  
–13641-- DWARF2 CFI reader: unhandled CFI instruction 0:50  
–13641-- DWARF2 CFI reader: unhandled CFI instruction 0:50  
–13641-- DWARF2 CFI reader: unhandled CFI instruction 0:50  
–13641-- DWARF2 CFI reader: unhandled CFI instruction 0:50  
ruby 1.9.0 (2007-09-22 patchlevel 0) [i686-linux]  
==13641== Invalid read of size 4  
==13641== at 0x80FB8B9: remove\_event\_hook (thread.c:2709)  
==13641== by 0x80FB92E: rb\_remove\_event\_hook (thread.c:2727)  
==13641== by 0x80FB9B0: rb\_clear\_trace\_func (thread.c:2749)  
==13641== by 0x805A1AB: ruby\_finalize\_1 (eval.c:146)  
==13641== by 0x805A297: ruby\_cleanup (eval.c:181)  
==13641== by 0x805A507: ruby\_run\_node (eval.c:256)  
==13641== by 0x80576C4: main (main.c:46)  
==13641== Address 0x42FDEDC is 12 bytes inside a block of size 16  
free’d  
==13641== at 0x401CFA5: free (vg\_replace\_malloc.c:233)  
==13641== by 0x8060FCF: ruby\_xfree (gc.c:328)  
==13641== by 0x80FB8AF: remove\_event\_hook (thread.c:2706)  
==13641== by 0x80FB92E: rb\_remove\_event\_hook (thread.c:2727)  
==13641== by 0x80FB9B0: rb\_clear\_trace\_func (thread.c:2749)  
==13641== by 0x805A1AB: ruby\_finalize\_1 (eval.c:146)  
==13641== by 0x805A297: ruby\_cleanup (eval.c:181)  
==13641== by 0x805A507: ruby\_run\_node (eval.c:256)  
==13641== by 0x80576C4: main (main.c:46)  
==13641==  
==13641== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 19 from  
1)  
==13641== malloc/free: in use at exit: 914,049 bytes in 6,533 blocks.  
==13641== malloc/free: 6,939 allocs, 406 frees, 937,224 bytes allocated.  
==13641== For counts of detected errors, rerun with: -v  
==13641== searching for pointers to 6,533 not-freed blocks.  
==13641== checked 697,756 bytes.  
==13641==  
==13641== LEAK SUMMARY:  
==13641== definitely lost: 0 bytes in 0 blocks.  
==13641== possibly lost: 68 bytes in 1 blocks.  
==13641== still reachable: 913,981 bytes in 6,532 blocks.  
==13641== suppressed: 0 bytes in 0 blocks.  
==13641== Reachable blocks (those to which a pointer was found) are not  
shown.  
==13641== To see them, rerun with: --show-reachable=yes

---

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [September 24, 2007, 1:59am UTC](https://www.ruby-forum.com/t/valgrind-set-trace-func/115263/2 "2007-09-24T01:59:07Z")

</div>

In article [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid),  
Tanaka A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

> e$B0J2\<$N$h$&$K$9$k$He(B Invalid read of size 4 e$B$H$J$j$^$9!#e(B
> 
> % valgrind ./ruby -ve ‘set\_trace\_func(proc {})’

> ==13641== at 0x80FB8B9: remove\_event\_hook (thread.c:2709)

1.8 e$B$Ne(B rb\_remove\_event\_hook e$B$H8+Hf$Y$k$H!“e(Breturn  
e$B$,$R$H$D\>Ce(B  
e$B$($F$$$k$h$&$J$N$G$9$,!”$J$s$G$G$7$g$&e(B?

---

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [September 28, 2007, 8:25am UTC](https://www.ruby-forum.com/t/valgrind-set-trace-func/115263/3 "2007-09-28T08:25:53Z")

</div>

In article [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid),  
Tanaka A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

> 1.8 e$B$Ne(B rb\_remove\_event\_hook e$B$H8+Hf$Y$k$H!“e(Breturn e$B$,$R$H$D\>Ce(B  
> e$B$($F$$$k$h$&$J$N$G$9$,!”$J$s$G$G$7$g$&e(B?

e$B0UL#$,$o$+$C$F$^$;$s$,!“8+Hf$Y$k$@$1$G$I$&$K$+$9$k$J$i!”$3$&e(B  
e$B$$$&$3$H$J$s$G$7$g$&$+e(B?

# Index: thread.c

— thread.c (e$B%j%S%8%g%se(B 13542)  
+++ thread.c (e$B:n6H%3%T!\<e(B)  
@@ -2704,6 +2704,7 @@  
\*root = hook-\>next;  
}  
xfree(hook);

- 

```
       return 0;

```

}  
prev = hook;  
hook = hook-\>next;