Thanks for the explanation Padraig, Eric, Eric:
On Tue, Sep 22, 2009 at 1:12 AM, Eric Day <[email protected]> wrote: > If > you're hitting a bug where there is an invalid address in one of the > pointers, something was not properly cleaned up previously. This is the bug that I was referring to: https://bugs.launchpad.net/drizzle/+bug/432210 While I managed to fix them, I don't really like the solution I came up with for the second crash (only call drizzle_result_free(&res); if we got a DRIZZLE_RETURN_OK I tried to find where all pointer in res were supposed to be freed, but I couldn't :( Thanks Diego > > -Eric > > On Mon, Sep 21, 2009 at 10:19:58PM -0400, Padraig O'Sullivan wrote: >> On Mon, Sep 21, 2009 at 9:53 PM, Diego Medina <[email protected]> wrote: >> > Hi, >> > >> > In libdrizzle/column.c:355 we have: >> > >> > void drizzle_column_free(drizzle_column_st *column) >> > { >> > if (column->result->column_list == column) >> > column->result->column_list= column->next; >> > if (column->prev) >> > column->prev->next= column->next; >> > if (column->next) >> > column->next->prev= column->prev; >> > >> > if (column->options & DRIZZLE_COLUMN_ALLOCATED) >> > free(column); >> > } >> > >> > why can't is just be >> > >> > if (column->options & DRIZZLE_COLUMN_ALLOCATED) >> > free(column); >> >> From not knowing the above code, it looks to me like it is removing >> column from a doubly-linked list before freeing the memory allocated >> for column. This statement: >> >> if (column->result->column_list == column) >> column->result->column_list= column->next; >> >> looks like it modifies the head of the linked list i.e. if the node to >> be deleted is the head, modify the head to point to the next in the >> list. >> >> These statements: >> >> if (column->prev) >> column->prev->next= column->next; >> if (column->next) >> column->next->prev= column->prev; >> >> just splice the node to be deleted out of the linked list by modifying >> the successor and predecessor pointers of column's successor and >> predecessor. >> >> So yeah, I would assume this code is needed. >> >> -Padraig >> >> > >> > ? >> > >> > Thanks >> > >> > -Diego >> > >> > P.S. oh, why do I ask, there are times when >> > column->result->column_list points to an address that cannot be >> > accessed (like in this bug >> > https://bugs.launchpad.net/drizzle/+bug/432210 ) >> > I fixed that one bug, but now I see a new one because >> > column->prev->next is in an address that cannot be accessed :| >> > >> > >> > >> > >> > >> > -- >> > Diego Medina >> > Web Developer >> > http://www.fmpwizard.com >> > >> > _______________________________________________ >> > Mailing list: https://launchpad.net/~drizzle-discuss >> > Post to : [email protected] >> > Unsubscribe : https://launchpad.net/~drizzle-discuss >> > More help : https://help.launchpad.net/ListHelp >> > >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~drizzle-discuss >> Post to : [email protected] >> Unsubscribe : https://launchpad.net/~drizzle-discuss >> More help : https://help.launchpad.net/ListHelp > -- Diego Medina Web Developer http://www.fmpwizard.com _______________________________________________ Mailing list: https://launchpad.net/~drizzle-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~drizzle-discuss More help : https://help.launchpad.net/ListHelp
