https://bugs.kde.org/show_bug.cgi?id=392855
David Rankin <drankina...@suddenlinkmail.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|INVALID |---
Ever confirmed|0 |1
Status|RESOLVED |REOPENED
--- Comment #2 from David Rankin <drankina...@suddenlinkmail.com> ---
There is definitely a problem with either valgrind or libc. For Example,
OpenSuSE Leap 42.3 correctly reports the number of allocations and the amount
of memory allocated.
$ valgrind ./bin/vgtest2
==4142== Memcheck, a memory error detector
==4142== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==4142== Using Valgrind-3.12.0 and LibVEX; rerun with -h for copyright info
==4142== Command: ./bin/vgtest2
==4142==
a: 5
==4142==
==4142== HEAP SUMMARY:
==4142== in use at exit: 0 bytes in 0 blocks
==4142== total heap usage: 1 allocs, 1 frees, 4 bytes allocated
==4142==
==4142== All heap blocks were freed -- no leaks are possible
==4142==
==4142== For counts of detected and suppressed errors, rerun with: -v
==4142== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
That is with:
gcc --version
gcc (SUSE Linux) 4.8.5
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
The assembly generated is:
$ gcc -S -Ofast -o vgtest2.asm vgtest2.c
$ cat vgtest2.asm
.file "vgtest2.c"
.section .rodata.str1.1,"aMS",@progbits,1
.LC0:
.string "a: %d\n"
.section .text.startup,"ax",@progbits
.p2align 4,,15
.globl main
.type main, @function
main:
.LFB21:
.cfi_startproc
pushq %rbx
.cfi_def_cfa_offset 16
.cfi_offset 3, -16
movl $4, %edi
call malloc
movl $5, %esi
movq %rax, %rbx
movl $5, (%rax)
movl $.LC0, %edi
xorl %eax, %eax
call printf
movq %rbx, %rdi
call free
popq %rbx
.cfi_def_cfa_offset 8
ret
.cfi_endproc
.LFE21:
.size main, .-main
.ident "GCC: (SUSE Linux) 4.8.5"
.section .note.GNU-stack,"",@progbits
Now on Archlinux, valgrind incorrectly reports the amount of memory allocated:
$ gcc --version
gcc (GCC) 7.3.1 20180406
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ valgrind ./bin/vgtest2
==8639== Memcheck, a memory error detector
==8639== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==8639== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==8639== Command: ./bin/vgtest2
==8639==
a: 5
==8639==
==8639== HEAP SUMMARY:
==8639== in use at exit: 0 bytes in 0 blocks
==8639== total heap usage: 1 allocs, 1 frees, 1,024 bytes allocated
==8639==
==8639== All heap blocks were freed -- no leaks are possible
==8639==
==8639== For counts of detected and suppressed errors, rerun with: -v
==8639== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
The generated assembly is different:
gcc -S -Ofast -o vgtest2.asm vgtest2.c
$ cat vgtest2.asm
.file "vgtest2.c"
.text
.section .rodata.str1.1,"aMS",@progbits,1
.LC0:
.string "a: %d\n"
.section .text.startup,"ax",@progbits
.p2align 4,,15
.globl main
.type main, @function
main:
.LFB24:
.cfi_startproc
leaq .LC0(%rip), %rdi
subq $8, %rsp
.cfi_def_cfa_offset 16
movl $5, %esi
xorl %eax, %eax
call printf@PLT
xorl %eax, %eax
addq $8, %rsp
.cfi_def_cfa_offset 8
ret
.cfi_endproc
.LFE24:
.size main, .-main
.ident "GCC: (GNU) 7.3.1 20180406"
.section .note.GNU-stack,"",@progbits
Now something is broken in the valgrind reporting of memory allocated. It can't
work correctly -- and then not work correctly -- and ho, hum, something must
have change.... Yes, there is a bug somewhere.
If this isn't a valgrind bug, then I would appreciate suggestions on who the
proper owner for the bug is.
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