objective c - EXC_BAD_ACCESS error when removing object from NSMutableDictionary -

i have nsmutabledictionary datasource uitableview. trying implement delete mode , having issue.

i logging key trying remove object corresponds issue seems might related trying access unallocated memory or something. here implementation of tableview:commiteditionstyle:forrowatindexpath:

    - (void)tableview:(uitableview *)tableview commiteditingstyle:(uitableviewcelleditingstyle)editingstyle forrowatindexpath:(nsindexpath *)indexpath {      if (editingstyle == uitableviewcelleditingstyledelete) {         // delete row data source.         nsarray * keys = [userlist allkeys];         nsnumber *keytoremove = [keys objectatindex:indexpath.row];         nslog(@"key remove: %@",keytoremove);         nslog(@"object @ key: %@",[userlist objectforkey:keytoremove]);            [userlist removeobjectforkey:keytoremove];                  [tableview deleterowsatindexpaths:[nsarray arraywithobject:indexpath] withrowanimation:uitableviewrowanimationfade];         [keys release];         [keytoremove release];      }        else if (editingstyle == uitableviewcelleditingstyleinsert) {         // create new instance of appropriate class, insert array, , add new row table view.     }    } 

this method runs , error. 2 nslog statements output correct key , it's corresponding value.

can tell me i'm doing wrong?

thanks

you don't own keys or keystoremove, should not releasing them. suggest reading on cocoa memory management rules.