问题
I have this basic Hello World code :
#include <stdio.h>
int main() {printf("Hello World !"); return 0;}
Then valgrind return me this summary :
HEAP SUMMARY:
==17840== in use at exit: 22,114 bytes in 160 blocks
==17840== total heap usage: 176 allocs, 16 frees, 28,258 bytes allocated
==17840==
==17840== LEAK SUMMARY:
==17840== definitely lost: 7,960 bytes in 63 blocks
==17840== indirectly lost: 6,888 bytes in 8 blocks
==17840== possibly lost: 72 bytes in 3 blocks
==17840== still reachable: 32 bytes in 1 blocks
==17840== suppressed: 7,162 bytes in 85 blocks
According to valgrind's documentations, "definitively lost" means fixable leaks, however I don't see any fixable leak, so :
Is my valgrind broken ?
(I'm on OSX Sierra 10.12.4)
Edit: Definitively my OSX version(On my Linux, I go for "no leaks are possible"), I'll update soon, and I'll edit this again when it's done
回答1:
You have to ask to get the leak information. I am working on macOS Sierra 10.12.6 (you should upgrade; there are key security issues fixed between 10.12.4 and 10.12.6). I'm using Valgrind built from SVN (Subversion — though it is about to switch to using Git instead).
With no extra options
I have a binary search tree program and I just removed the call to the memory free function, and ran it under my version of valgrind:
$ valgrind --suppressions=etc/suppressions-macos-10.12.5 -- ./bst29
==5095== Memcheck, a memory error detector
==5095== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==5095== Using Valgrind-3.13.0.SVN and LibVEX; rerun with -h for copyright info
==5095== Command: ./bst29
==5095==
1 3 5 7 10 18 20
==5095==
==5095== HEAP SUMMARY:
==5095== in use at exit: 22,476 bytes in 170 blocks
==5095== total heap usage: 186 allocs, 16 frees, 28,620 bytes allocated
==5095==
==5095== LEAK SUMMARY:
==5095== definitely lost: 24 bytes in 1 blocks
==5095== indirectly lost: 144 bytes in 6 blocks
==5095== possibly lost: 0 bytes in 0 blocks
==5095== still reachable: 0 bytes in 0 blocks
==5095== suppressed: 22,308 bytes in 163 blocks
==5095== Rerun with --leak-check=full to see details of leaked memory
==5095==
==5095== For counts of detected and suppressed errors, rerun with: -v
==5095== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 5 from 5)
$
Requesting --leak-check=full
Note the Rerun with --leak-check=full to see details of leaked memory message:
$ valgrind --leak-check=full --suppressions=etc/suppressions-macos-10.12.5 -- ./bst29
==5098== Memcheck, a memory error detector
==5098== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==5098== Using Valgrind-3.13.0.SVN and LibVEX; rerun with -h for copyright info
==5098== Command: ./bst29
==5098==
1 3 5 7 10 18 20
==5098==
==5098== HEAP SUMMARY:
==5098== in use at exit: 22,476 bytes in 170 blocks
==5098== total heap usage: 186 allocs, 16 frees, 28,620 bytes allocated
==5098==
==5098== 168 (24 direct, 144 indirect) bytes in 1 blocks are definitely lost in loss record 30 of 45
==5098== at 0x100096861: malloc (vg_replace_malloc.c:302)
==5098== by 0x100000C50: main (bst29.c:30)
==5098==
==5098== LEAK SUMMARY:
==5098== definitely lost: 24 bytes in 1 blocks
==5098== indirectly lost: 144 bytes in 6 blocks
==5098== possibly lost: 0 bytes in 0 blocks
==5098== still reachable: 0 bytes in 0 blocks
==5098== suppressed: 22,308 bytes in 163 blocks
==5098==
==5098== For counts of detected and suppressed errors, rerun with: -v
==5098== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 14 from 14)
$
After fixing the bst29.c program
With the tree freeing code reactivated, the output is:
$ valgrind --leak-check=full --suppressions=etc/suppressions-macos-10.12.5 -- ./bst29
==5124== Memcheck, a memory error detector
==5124== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==5124== Using Valgrind-3.13.0.SVN and LibVEX; rerun with -h for copyright info
==5124== Command: ./bst29
==5124==
1 3 5 7 10 18 20
==5124==
==5124== HEAP SUMMARY:
==5124== in use at exit: 22,308 bytes in 163 blocks
==5124== total heap usage: 186 allocs, 23 frees, 28,620 bytes allocated
==5124==
==5124== LEAK SUMMARY:
==5124== definitely lost: 0 bytes in 0 blocks
==5124== indirectly lost: 0 bytes in 0 blocks
==5124== possibly lost: 0 bytes in 0 blocks
==5124== still reachable: 0 bytes in 0 blocks
==5124== suppressed: 22,308 bytes in 163 blocks
==5124==
==5124== For counts of detected and suppressed errors, rerun with: -v
==5124== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 14 from 14)
$
That's the normal result for me on a Mac — a leak summary with everything suppressed.
Suppressions file
The suppressions file listed contains 10 entries for various forms of system leak:
{
macOS-Sierra-10.12.5-Leak.1
Memcheck:Leak
match-leak-kinds: reachable
fun:malloc_zone_malloc
fun:NXCreateMapTableFromZone
fun:NXCreateMapTableFromZone
fun:_ZL18__sel_registerNamePKcii
fun:sel_init
fun:map_images_nolock
fun:_ZN11objc_object21sidetable_retainCountEv
fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoEbb
fun:_ZN4dyld21registerObjCNotifiersEPFvjPKPKcPKPK11mach_headerEPFvS1_S6_ESC_
fun:_dyld_objc_notify_register
fun:_objc_init
fun:_os_object_init
}
{
macOS-Sierra-10.12.5-Leak.2
Memcheck:Leak
match-leak-kinds: reachable
fun:malloc_zone_malloc
fun:NXCreateHashTableFromZone
fun:NXCreateHashTable
fun:NXCreateMapTableFromZone
fun:NXCreateMapTableFromZone
fun:_ZL18__sel_registerNamePKcii
fun:sel_init
fun:map_images_nolock
fun:_ZN11objc_object21sidetable_retainCountEv
fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoEbb
fun:_ZN4dyld21registerObjCNotifiersEPFvjPKPKcPKPK11mach_headerEPFvS1_S6_ESC_
fun:_dyld_objc_notify_register
}
{
macOS-Sierra-10.12.5-Leak.3
Memcheck:Leak
match-leak-kinds: reachable
fun:malloc_zone_malloc
fun:NXCreateHashTableFromZone
fun:NXCreateHashTable
fun:NXCreateMapTableFromZone
fun:NXCreateMapTableFromZone
fun:_ZL18__sel_registerNamePKcii
fun:sel_init
fun:map_images_nolock
fun:_ZN11objc_object21sidetable_retainCountEv
fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoEbb
fun:_ZN4dyld21registerObjCNotifiersEPFvjPKPKcPKPK11mach_headerEPFvS1_S6_ESC_
fun:_dyld_objc_notify_register
}
{
macOS-Sierra-10.12.5-Leak.4
Memcheck:Leak
match-leak-kinds: reachable
fun:malloc
fun:NXCreateHashTableFromZone
fun:NXCreateHashTable
fun:NXCreateMapTableFromZone
fun:NXCreateMapTableFromZone
fun:_ZL18__sel_registerNamePKcii
fun:sel_init
fun:map_images_nolock
fun:_ZN11objc_object21sidetable_retainCountEv
fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoEbb
fun:_ZN4dyld21registerObjCNotifiersEPFvjPKPKcPKPK11mach_headerEPFvS1_S6_ESC_
fun:_dyld_objc_notify_register
}
{
macOS-Sierra-10.12.5-Leak.5
Memcheck:Leak
match-leak-kinds: reachable
fun:malloc
fun:NXCreateMapTableFromZone
fun:NXCreateMapTableFromZone
fun:_ZL18__sel_registerNamePKcii
fun:sel_init
fun:map_images_nolock
fun:_ZN11objc_object21sidetable_retainCountEv
fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoEbb
fun:_ZN4dyld21registerObjCNotifiersEPFvjPKPKcPKPK11mach_headerEPFvS1_S6_ESC_
fun:_dyld_objc_notify_register
fun:_objc_init
fun:_os_object_init
}
{
macOS-Sierra-10.12.5-Leak.6
Memcheck:Leak
match-leak-kinds: reachable
fun:malloc_zone_calloc
fun:_NXHashRehashToCapacity
fun:NXHashInsert
fun:NXCreateHashTableFromZone
fun:NXCreateHashTable
fun:NXCreateMapTableFromZone
fun:NXCreateMapTableFromZone
fun:_ZL18__sel_registerNamePKcii
fun:sel_init
fun:map_images_nolock
fun:_ZN11objc_object21sidetable_retainCountEv
fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoEbb
}
{
macOS-Sierra-10.12.5-Leak.7
Memcheck:Leak
match-leak-kinds: possible
fun:calloc
fun:map_images_nolock
fun:_ZN11objc_object21sidetable_retainCountEv
fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoEbb
fun:_ZN4dyld21registerObjCNotifiersEPFvjPKPKcPKPK11mach_headerEPFvS1_S6_ESC_
fun:_dyld_objc_notify_register
fun:_objc_init
fun:_os_object_init
fun:libdispatch_init
fun:libSystem_initializer
fun:_ZN16ImageLoaderMachO18doModInitFunctionsERKN11ImageLoader11LinkContextE
fun:_ZN16ImageLoaderMachO16doInitializationERKN11ImageLoader11LinkContextE
}
{
macOS-Sierra-10.12.5-reachable.1
Memcheck:Leak
match-leak-kinds: reachable
fun:malloc_zone_calloc
fun:_NXHashRehashToCapacity
fun:NXHashInsert
fun:NXCreateHashTableFromZone
fun:NXCreateHashTable
fun:NXCreateMapTableFromZone
fun:NXCreateMapTableFromZone
fun:_ZL18__sel_registerNamePKcii
fun:sel_init
fun:map_images_nolock
fun:_ZN11objc_object21sidetable_retainCountEv
fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoEbb
}
{
macOS-Sierra-10.12.5-possible.1
Memcheck:Leak
match-leak-kinds: possible
fun:calloc
fun:map_images_nolock
fun:_ZN11objc_object21sidetable_retainCountEv
fun:_ZN4dyldL18notifyBatchPartialE17dyld_image_statesbPFPKcS0_jPK15dyld_image_infoEbb
fun:_ZN4dyld21registerObjCNotifiersEPFvjPKPKcPKPK11mach_headerEPFvS1_S6_ESC_
fun:_dyld_objc_notify_register
fun:_objc_init
fun:_os_object_init
fun:libdispatch_init
fun:libSystem_initializer
fun:_ZN16ImageLoaderMachO18doModInitFunctionsERKN11ImageLoader11LinkContextE
fun:_ZN16ImageLoaderMachO16doInitializationERKN11ImageLoader11LinkContextE
}
{
macOS-Sierra-10.12.5-check.1
Memcheck:Param
msg->desc.port.name
fun:mach_msg_trap
fun:mach_msg
fun:task_set_special_port
fun:_os_trace_create_debug_control_port
fun:_libtrace_init
fun:libSystem_initializer
fun:_ZN16ImageLoaderMachO18doModInitFunctionsERKN11ImageLoader11LinkContextE
fun:_ZN16ImageLoaderMachO16doInitializationERKN11ImageLoader11LinkContextE
fun:_ZN11ImageLoader23recursiveInitializationERKNS_11LinkContextEjPKcRNS_21InitializerTimingListERNS_15UninitedUpwardsE
fun:_ZN11ImageLoader23recursiveInitializationERKNS_11LinkContextEjPKcRNS_21InitializerTimingListERNS_15UninitedUpwardsE
fun:_ZN11ImageLoader19processInitializersERKNS_11LinkContextEjRNS_21InitializerTimingListERNS_15UninitedUpwardsE
fun:_ZN11ImageLoader15runInitializersERKNS_11LinkContextERNS_21InitializerTimingListE
}
They all come from the startup code before main() is called; there is nothing I can do about any of them, therefore.
来源：https://stackoverflow.com/questions/45527113/is-my-valgrind-installation-broken