檢查 memory leak

安裝 valgrind

$ sudo apt update

$ sudo apt install snapd

$ sudo snap install valgrind --classic

$ gcc -g -o debug_prog debug_prog.c

$ g++ -g -o debug_prog debug_prog.c

開啟兩個 terminal

$ valgrind --vgdb=yes --vgdb-error=0 --tool=memcheck --leak-check=full ./debug_prog

$ gdb ./debug_prog

(gdb) target remote | vgdb

(gdb) break linenum

(gdb) next

(gdb) step

(gdb) monitor leak_check full reachable any

(gdb) kill

(gdb) quit

若只是單純檢查 memory leak

$ valgrind --tool=memcheck --leak-check=full ./debug_prog

suppression 一些錯誤

$ valgrind --tool=memcheck --leak-check=full --gen-suppressions=all ./debug_prog

...

{

   <insert_a_suppression_name_here>

   Memcheck:Leak

   match-leak-kinds: definite

   fun:malloc

   fun:g_malloc

   obj:/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0.5600.4

   fun:call_init

   fun:_dl_init

   obj:/lib/x86_64-linux-gnu/ld-2.27.so

}

...

利用上個命令的輸出，產生 local.supp 檔

$ valgrind --tool=memcheck --leak-check=full --supressions=./local.supp ./debug_prog

$ valgrind --tool=memcheck --leak-check=full --gen-suppressions=all --log-file=supp.log --supressions=./local.supp ./debug_prog

$ cat ./supp.log | ./suppressions.sh > local.supp

$ valgrind --tool=memcheck --leak-check=full --supressions=./local.supp --supressions=./gtk.supp ./debug_prog

suppressions.sh 若產生下列錯誤

awk: 34: unexpected character '&'

需改變 awk 的版本為 gawk

$ awk -W version

$ sudo apt-get update

$ sudo apt-get install gawk

去除 definitely loss

== 16,384 bytes in 1 blocks are definitely lost in loss record 1,443 of 1,448

==    at 0x4C330C5: malloc (vg_replace_malloc.c:393)

==    by 0x6A0BBD8: g_malloc (gmem.c:99)

==    by 0x6A1674B: g_quark_init (gquark.c:62)

==    by 0x40108D2: call_init (dl-init.c:72)

==    by 0x40108D2: _dl_init (dl-init.c:119)

==    by 0x40010C9: ??? (in /lib/x86_64-linux-gnu/ld-2.27.so)

下載 gst.supp 和 glib.supp gtk.supp

https://gitlab.freedesktop.org/gstreamer/common/-/blob/master/gst.supp

https://github.com/GNOME/glib/blob/main/tools/glib.supp

https://gist.github.com/pendingchaos/81feddb95c06aeb58e2f

Makefile 的

CFLAGS+= -g -O0

安裝 libglib 的 debug symbols 版本

$ echo "deb http://ddebs.ubuntu.com $(lsb_release -cs) main restricted universe multiverse

deb http://ddebs.ubuntu.com $(lsb_release -cs)-updates main restricted universe multiverse

deb http://ddebs.ubuntu.com $(lsb_release -cs)-proposed main restricted universe multiverse" | \

sudo tee -a /etc/apt/sources.list.d/ddebs.list

$ sudo apt install ubuntu-dbgsym-keyring

$ sudo apt update

$ sudo apt install libglib2.0-bin-dbgsym libglib2.0-0-dbgsym libglib2.0-dev-bin-dbgsym

export G_DEBUG=gc-friendly

export G_SLICE=always-malloc

valgrind -v --time-stamp=yes --tool=memcheck --leak-check=full \

  --gen-suppressions=all --log-file=supp.log \

  --suppressions=./glib.supp \

  --suppressions=./gst.supp \

  --suppressions=./gtk.supp \

  ./main

常用觀測記憶體使用狀態命令

$ while true; do echo -n `date +"%Y/%m/%d %H:%M:%S"`" " | tee -a aaa.log ; grep "VmRSS" /proc/26885/status | tee -a aaa.log ; sleep 60 ; done

$ watch "grep 'VmRSS\|VmPeak\|VmData\|VmStk\|VmExe\|VmLib\|Threads' /proc/26885/status"