Commit c2120c40 authored by svoj@mysql.com/june.mysql.com's avatar svoj@mysql.com/june.mysql.com
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BUG#27564 - Valgrind: UDF does not cleanup correctly 

Dropping an user defined function may cause server crash in
case this function is still in use by another thread.

The problem was that our hash implementation didn't update
hash link list properly when hash_update() was called.
parent 78e900dd

mysys/hash.c

+19 −0
Original line number Diff line number Diff line
@@ -572,6 +572,25 @@ my_bool hash_update(HASH *hash,byte *record,byte *old_key,uint old_key_length) 
    previous->next=pos->next;		/* unlink pos */



  /* Move data to correct position */

  if (new_index == empty)

  {

    /*

      At this point record is unlinked from the old chain, thus it holds

      random position. By the chance this position is equal to position

      for the first element in the new chain. That means updated record

      is the only record in the new chain.

    */

    if (empty != idx)

    {

      /*

        Record was moved while unlinking it from the old chain.

        Copy data to a new position.

      */

      data[empty]= org_link;

    }

    data[empty].next= NO_RECORD;

    DBUG_RETURN(0);

  }

  pos=data+new_index;

  new_pos_index=hash_rec_mask(hash,pos,blength,records);

  if (new_index != new_pos_index)