Ubuntu
glibc package

libc timer_create with option SIGEV_THREAD system call having memory leaks after timer_delete system call

Bug #1993530 reported by Vikas Kumar
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
gcc-9 (Ubuntu)
Invalid
Undecided
Unassigned
glibc (Ubuntu)
Triaged
Low
Unassigned

Bug Description

I have following ubuntu environment:

Description: Ubuntu 20.04.1 LTS
Release: 20.04
gcc 9.4.0
Linux version 5.15.0-48-generic
libc-2.31.so

I am using libc timer_create system call with option SIGEV_THREAD to create a timer, My timer functionality is working fine but when I exit my code after successfully deletion of timer using timer_delete system call I am getting 272 bytes of memory leak in valgrind report.

I have attached my sample application(timer_app.c). Please review and let me know if I am doing anything wrong here.

below is the valgrind memory leak snippet

==682959== 272 bytes in 1 blocks are possibly lost in loss record 1 of 1
==682959== at 0x483DD99: calloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==682959== by 0x40149DA: allocate_dtv (dl-tls.c:286)
==682959== by 0x40149DA: _dl_allocate_tls (dl-tls.c:532)
==682959== by 0x4A65322: allocate_stack (allocatestack.c:622)
==682959== by 0x4A65322: pthread_create@@GLIBC_2.2.5 (pthread_create.c:660)
==682959== by 0x4865BCC: __start_helper_thread (timer_routines.c:176)
==682959== by 0x4A6D4DE: __pthread_once_slow (pthread_once.c:116)
==682959== by 0x48649A2: timer_create@@GLIBC_2.3.3 (timer_create.c:101)
==682959== by 0x1092F1: SupTimerInit (in /home/vikas/a.out)
==682959== by 0x109490: main (in /home/vikas/a.out)

=======================================================================
complete valgrind dump
==682959== Memcheck, a memory error detector
==682959== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==682959== Using Valgrind-3.15.0-608cb11914-20190413 and LibVEX; rerun with -h for copyright info
==682959== Command: ./a.out
==682959== Parent PID: 681415
==682959==
--682959--
--682959-- Valgrind options:
--682959-- --leak-check=full
--682959-- --show-leak-kinds=all
--682959-- --track-origins=yes
--682959-- --verbose
--682959-- --log-file=valgrind-out.txt
--682959-- Contents of /proc/version:
--682959-- Linux version 5.15.0-48-generic (buildd@lcy02-amd64-043) (gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0, GNU ld (GNU Binutils for Ubuntu) 2.34) #54~20.04.1-Ubuntu SMP Thu Sep 1 16:17:26 UTC 2022
--682959--
--682959-- Arch and hwcaps: AMD64, LittleEndian, amd64-cx16-lzcnt-rdtscp-sse3-ssse3-avx-avx2-bmi-f16c-rdrand
--682959-- Page sizes: currently 4096, max supported 4096
--682959-- Valgrind library directory: /usr/lib/x86_64-linux-gnu/valgrind
--682959-- Reading syms from /home/vikas/a.out
--682959-- Reading syms from /usr/lib/x86_64-linux-gnu/ld-2.31.so
--682959-- Considering /usr/lib/debug/.build-id/45/87364908de169dec62ffa538170118c1c3a078.debug ..
--682959-- .. build-id is valid
--682959-- Reading syms from /usr/lib/x86_64-linux-gnu/valgrind/memcheck-amd64-linux
--682959-- object doesn't have a symbol table
--682959-- object doesn't have a dynamic symbol table
--682959-- Scheduler: using generic scheduler lock implementation.
--682959-- Reading suppressions file: /usr/lib/x86_64-linux-gnu/valgrind/default.supp
==682959== embedded gdbserver: reading from /tmp/vgdb-pipe-from-vgdb-to-682959-by-vikas-on-???
==682959== embedded gdbserver: writing to /tmp/vgdb-pipe-to-vgdb-from-682959-by-vikas-on-???
==682959== embedded gdbserver: shared mem /tmp/vgdb-pipe-shared-mem-vgdb-682959-by-vikas-on-???
==682959==
==682959== TO CONTROL THIS PROCESS USING vgdb (which you probably
==682959== don't want to do, unless you know exactly what you're doing,
==682959== or are doing some strange experiment):
==682959== /usr/lib/x86_64-linux-gnu/valgrind/../../bin/vgdb --pid=682959 ...command...
==682959==
==682959== TO DEBUG THIS PROCESS USING GDB: start GDB like this
==682959== /path/to/gdb ./a.out
==682959== and then give GDB the following command
==682959== target remote | /usr/lib/x86_64-linux-gnu/valgrind/../../bin/vgdb --pid=682959
==682959== --pid is optional if only one valgrind process is running
==682959==
--682959-- REDIR: 0x4022e20 (ld-linux-x86-64.so.2:strlen) redirected to 0x580c9ce2 (???)
--682959-- REDIR: 0x4022bf0 (ld-linux-x86-64.so.2:index) redirected to 0x580c9cfc (???)
--682959-- Reading syms from /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_core-amd64-linux.so
--682959-- object doesn't have a symbol table
--682959-- Reading syms from /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so
--682959-- object doesn't have a symbol table
==682959== WARNING: new redirection conflicts with existing -- ignoring it
--682959-- old: 0x04022e20 (strlen ) R-> (0000.0) 0x580c9ce2 ???
--682959-- new: 0x04022e20 (strlen ) R-> (2007.0) 0x0483f060 strlen
--682959-- REDIR: 0x401f600 (ld-linux-x86-64.so.2:strcmp) redirected to 0x483ffd0 (strcmp)
--682959-- REDIR: 0x4023380 (ld-linux-x86-64.so.2:mempcpy) redirected to 0x4843a20 (mempcpy)
--682959-- Reading syms from /usr/lib/x86_64-linux-gnu/librt-2.31.so
--682959-- Considering /usr/lib/debug/.build-id/ce/016c975d94bc4770ed8c62d45dea6b71405a2c.debug ..
--682959-- .. build-id is valid
--682959-- Reading syms from /usr/lib/x86_64-linux-gnu/libc-2.31.so
--682959-- Considering /usr/lib/debug/.build-id/18/78e6b475720c7c51969e69ab2d276fae6d1dee.debug ..
--682959-- .. build-id is valid
--682959-- Reading syms from /usr/lib/x86_64-linux-gnu/libpthread-2.31.so
--682959-- Considering /usr/lib/debug/.build-id/7b/4536f41cdaa5888408e82d0836e33dcf436466.debug ..
--682959-- .. build-id is valid
--682959-- REDIR: 0x490a480 (libc.so.6:memmove) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4909780 (libc.so.6:strncpy) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490a7b0 (libc.so.6:strcasecmp) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x49090a0 (libc.so.6:strcat) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x49097e0 (libc.so.6:rindex) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490bc50 (libc.so.6:rawmemchr) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4926ce0 (libc.so.6:wmemchr) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4926820 (libc.so.6:wcscmp) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490a5e0 (libc.so.6:mempcpy) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490a410 (libc.so.6:bcmp) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4909710 (libc.so.6:strncmp) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4909150 (libc.so.6:strcmp) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490a540 (libc.so.6:memset) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x49267e0 (libc.so.6:wcschr) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4909670 (libc.so.6:strnlen) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4909230 (libc.so.6:strcspn) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490a800 (libc.so.6:strncasecmp) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x49091d0 (libc.so.6:strcpy) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490a950 (libc.so.6:memcpy@@GLIBC_2.14) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4927f50 (libc.so.6:wcsnlen) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4926860 (libc.so.6:wcscpy) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4909820 (libc.so.6:strpbrk) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4909100 (libc.so.6:index) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4909630 (libc.so.6:strlen) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4912bb0 (libc.so.6:memrchr) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490a850 (libc.so.6:strcasecmp_l) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490a3d0 (libc.so.6:memchr) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4926930 (libc.so.6:wcslen) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x4909ae0 (libc.so.6:strspn) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490a750 (libc.so.6:stpncpy) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490a6f0 (libc.so.6:stpcpy) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490bc90 (libc.so.6:strchrnul) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x490a8a0 (libc.so.6:strncasecmp_l) redirected to 0x48331d0 (_vgnU_ifunc_wrapper)
--682959-- REDIR: 0x49f2500 (libc.so.6:__strrchr_avx2) redirected to 0x483ea10 (rindex)
--682959-- REDIR: 0x4905b10 (libc.so.6:calloc) redirected to 0x483dce0 (calloc)
--682959-- REDIR: 0x49046d0 (libc.so.6:free) redirected to 0x483c9d0 (free)
--682959-- REDIR: 0x49040e0 (libc.so.6:malloc) redirected to 0x483b780 (malloc)
--682959-- REDIR: 0x49f2310 (libc.so.6:__strchrnul_avx2) redirected to 0x4843540 (strchrnul)
--682959-- REDIR: 0x49f56c0 (libc.so.6:__mempcpy_avx_unaligned_erms) redirected to 0x4843660 (mempcpy)
--682959-- REDIR: 0x49f5b60 (libc.so.6:__memset_avx2_unaligned_erms) redirected to 0x48428e0 (memset)
==682959==
==682959== HEAP SUMMARY:
==682959== in use at exit: 272 bytes in 1 blocks
==682959== total heap usage: 6 allocs, 5 frees, 1,688 bytes allocated
==682959==
==682959== Searching for pointers to 1 not-freed blocks
==682959== Checked 116,416 bytes
==682959==
==682959== 272 bytes in 1 blocks are possibly lost in loss record 1 of 1
==682959== at 0x483DD99: calloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==682959== by 0x40149DA: allocate_dtv (dl-tls.c:286)
==682959== by 0x40149DA: _dl_allocate_tls (dl-tls.c:532)
==682959== by 0x4A65322: allocate_stack (allocatestack.c:622)
==682959== by 0x4A65322: pthread_create@@GLIBC_2.2.5 (pthread_create.c:660)
==682959== by 0x4865BCC: __start_helper_thread (timer_routines.c:176)
==682959== by 0x4A6D4DE: __pthread_once_slow (pthread_once.c:116)
==682959== by 0x48649A2: timer_create@@GLIBC_2.3.3 (timer_create.c:101)
==682959== by 0x1092F1: SupTimerInit (in /home/vikas/a.out)
==682959== by 0x109490: main (in /home/vikas/a.out)
==682959==
==682959== LEAK SUMMARY:
==682959== definitely lost: 0 bytes in 0 blocks
==682959== indirectly lost: 0 bytes in 0 blocks
==682959== possibly lost: 272 bytes in 1 blocks
==682959== still reachable: 0 bytes in 0 blocks
==682959== suppressed: 0 bytes in 0 blocks
==682959==
==682959== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

Regards,
Vikas

Revision history for this message
Benjamin Drung (bdrung) wrote :

Thank you for taking the time to report this bug and helping to make Ubuntu better. I don't see timer_app.c. Did you forget to attach it to the bug report?

Changed in gcc-9 (Ubuntu):
status: New → Incomplete
Revision history for this message
Vikas Kumar (vikasyada) wrote (last edit ):

Hi,

Thanks for pointing it out, Please find attached sample application.

Vikas Kumar (vikasyada)
Changed in gcc-9 (Ubuntu):
status: Incomplete → New
Revision history for this message
Dan Bungert (dbungert) wrote :

Reproduced using supplied sample application, thanks!
Moving component to glibc.

Dan Bungert (dbungert)
Changed in gcc-9 (Ubuntu):
status: New → Invalid
Changed in glibc (Ubuntu):
status: New → Triaged
importance: Undecided → Low
Revision history for this message
Michael Hudson-Doyle (mwhudson) wrote :

This is being discussed upstream at https://sourceware.org/bugzilla/show_bug.cgi?id=29705

William Wilson (jawn-smith)
tags: added: foundations-triage-discuss
To post a comment you must log in.
This report contains Public information  
Everyone can see this information.
Subscribing...

Other bug subscribers

Remote bug watches

Bug watches keep track of this bug in other bug trackers.