Slash is slamming the door on his ex-wife, Perla Ferrar ... blocking her from their son's huge Hollywood performance -- opening for Slash -- but it looks like she's totally ignoring the ban.
Sources close to Perla tell TMZ ... the Guns 'n Roses rocker banned her from attending the Tuesday night gig at the Hollywood Palladium -- 16-year-old London's band, Classless Act, will warm up the crowd before Slash takes the stage.
We're told someone from Slash's camp reached out to Perla and told her she wouldn't be able to attend. The bad blood between them is nothing new -- they just settled a drawn-out, contentious divorce that ended with him having to shell out serious gwap.
Despite the stay-away notice ... Perla said Monday she was planning to be at the show. She said on social media, "Can’t wait to see my baby boy London open for his father at this historical event tomorrow night! #icouldntbemoreproud."
Unclear if Slash is going to take more drastic steps to keep her out. We've reached out to his camp, but no word back yet.