That should prevent bleeding and crackling.
Chalk painting over stained wood.
Lightly sand with the 220 grit sandpaper over areas that feel rough to the touch apply 2nd coat of polyurethane.
First clean the stained surface with soapy water to remove any dust dirt and cobwebs.
Allow to dry overnight.
Sand any areas that feel rough and you re done.
Then follow these general preparatory steps for painting over stain.
Next to dull the stain lightly sand the surface with 150 grit or finer sandpaper moving in the direction of the grain.
Wipe off any excess paint around the paint cans using a clean rag before storing.
Apply with a high quality brush in a very thin coat.
The painting above a background might begin to peel.
If you use a light color paint the dark wood might bleed through.
Amy howard chalk paint in linen is what i used.
Use paint thinner to clean off brushes used for oil based paints.
There are numerous varieties of paints that are either sterile or solvent based that generates unique finishes that are measured by its sheen component.
And if you use a water base poly on top to seal it it may give you a crackle affect which you may or may not want.
Allow to dry overnight.
Stain over chalk paint though the paint is a little thicker than latex then it will not automatically cover in 1 jacket.
To eliminate these problems seal it with a coat of shellac first and then use your chalk paint.
Another chalk paint option is annie sloan old white.