On Thu, Mar 23, 2017 at 9:01 AM, Dan Kennedy <danielk1...@gmail.com> wrote:
> On 03/23/2017 10:00 PM, Subramaniyan, Ganesan (G.) wrote:
>
>> Hi,
>> We are facing dynamic memory pool corruption issue while using SQLite.
>> Based on our investigation we suspect SQLite freeing memory bypassing the
>> memory management API'S registered as below.
>>
>> We have registered the memory allocation routines as below.
>> static const sqlite3_mem_methods mqxmem = {
>> mqxMalloc,
>> mqxFree,
>> mqxRealloc,
>> mqxSize,
>> mqxRoundup,
>> mqxInit,
>> mqxShutdown,
>> NULL
>> };
>> sqlite3_config(SQLITE_CONFIG_MALLOC, &mqxmem);
>>
>> Despite this, is there any sort of configurations by which SQLite might
>> still use its own or standard library APIs to allocate/reallocate or free
>> the memory, bypassing the memory management APIs registered above?
>>
>
>
> No. Following a successful call to sqlite3_config() SQLite allocates and
> frees memory using the configured routines exclusively[1]. There are no
> direct calls to malloc()/free() or similar in the library.
>
> Are you checking the return value of sqlite3_config()? If
> sqlite3_initialize() or any other sqlite3_*() function has already been
> called when sqlite3_config() is invoked it will fail and the memory
> allocation routines will not be configured.
>
> https://sqlite.org/c3ref/config.html
>
> What symptoms are you seeing that suggest SQLite is bypassing your memory
> allocation functions?
>
There is an internal check to see if sqlite has alerady 'initialized' the
config needs to be set before it's initialized. There's a error thrown
void errorLogCallback(void *pArg, int iErrCode, const char *zMsg){
printf( "Sqlite3 Err: (%d) %s", iErrCode, zMsg);
}
sqlite3_config( SQLITE_CONFIG_LOG, errorLogCallback, 0);
that is sqlite3_config is called late it logs an 'invalid operation' sort
of message.
>
> Dan.
>
> [1] It may also make use of static buffers supplied by calls to
> sqlite3_config(SQLITE_CONFIG_HEAP), CONFIG_PAGECACHE or CONFIG_SCRATCH,
> but I'm guessing you have made no such calls. Most apps do not.
>
>
>
>
>
> We are using SQLite version 3.7.10 running on Freescale MQX hosted on ARM
>> A5 Cortex processor.
>> We have enabled SQLITE_ENABLE_MEMORY_MANAGEMENT configuration and using
>> sqlite3_release_memory()<https://www.sqlite.org/c3ref/release_memory.html>
>> very often, after every fetch/write operations.
>>
>> Thanks & Regards,
>> Ganesan.S
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>>
>
>
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