Re: [Valgrind-users] Timer delete

[John R. <jr...@bi...>]

On 11/11/22 13:23, Domenico Panella wrote:
> Operating System: Slackware 15.0 (Current) Kernel Version: 5.19.17 (64-bit) Graphics Platform: X11 Processors: 8 × Intel® Core™ i7-8565U CPU @ 1.80GHz
> 
> A small example:
> 
> #include<stdbool.h>
  [[snip horrible formatting]]
> 

It's a bug (or implementation constraint) in glibc timer.

When I run it under valgrind-3.19.0 with glibc-debuginfo and glibc-debugsource
installed (2.35-17.fc36.x86_64):  [Notice the annotation "LOOK HERE"]
=====
$ valgrind --leak-check=full --sim-hints=no-nptl-pthread-stackcache ./a.out
==281161== Memcheck, a memory error detector
==281161== Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al.
==281161== Using Valgrind-3.19.0 and LibVEX; rerun with -h for copyright info
==281161== Command: ./a.out
==281161==
--281161:0:   sched WARNING: pthread stack cache cannot be disabled!  <<<<< LOOK HERE <<<<<
==281161==
==281161== HEAP SUMMARY:
==281161==     in use at exit: 272 bytes in 1 blocks
==281161==   total heap usage: 3 allocs, 2 frees, 512 bytes allocated
==281161==
==281161== 272 bytes in 1 blocks are possibly lost in loss record 1 of 1
==281161==    at 0x484A464: calloc (vg_replace_malloc.c:1328)
==281161==    by 0x4012E42: UnknownInlinedFun (rtld-malloc.h:44)
==281161==    by 0x4012E42: allocate_dtv (dl-tls.c:375)
==281161==    by 0x4013841: _dl_allocate_tls (dl-tls.c:634)
==281161==    by 0x48F5A98: allocate_stack (allocatestack.c:428)
==281161==    by 0x48F5A98: pthread_create@@GLIBC_2.34 (pthread_create.c:647)
==281161==    by 0x4900864: __timer_start_helper_thread (timer_routines.c:147)
==281161==    by 0x48F9E36: __pthread_once_slow (pthread_once.c:116)
==281161==    by 0x49002CA: timer_create@@GLIBC_2.34 (timer_create.c:70)
==281161==    by 0x4011E2: main (timer.c:40)
==281161==
==281161== LEAK SUMMARY:
==281161==    definitely lost: 0 bytes in 0 blocks
==281161==    indirectly lost: 0 bytes in 0 blocks
==281161==      possibly lost: 272 bytes in 1 blocks
==281161==    still reachable: 0 bytes in 0 blocks
==281161==         suppressed: 0 bytes in 0 blocks
==281161==
==281161== For lists of detected and suppressed errors, rerun with: -s
==281161== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
=====