Chris Brown & Rihanna

Chris Brown was turned away at the Canadian border just hours before a scheduled concert and he handled the frustrating news with dignity and professionalism. No, really ... he did.

Brown tweeted, "The good people of the Canadian government wouldn't allow me entry. I'll be back this summer and will hopefully see all my Canadian fans!"

Brown was scheduled to play in Montreal Tuesday night and Toronto Wednesday night. According to Brown, both shows were sold out.

Canadian law dictates a person could be "criminally inadmissible" if they have been convicted of a crime involving assault.

Oh, right ... THAT.

Chris Brown has had his probation revoked in the Rihanna case, in part because he was present at 2 separate nightclubs when people inside were shot, and officials are worried about more shootings and think Chris should serve time behind bars.

Chris showed up for a progress report Thursday, when the judge told him the probation report presented multiple problems. First, the report mentions the shooting last Sunday in San Jose when Chris was on stage. Five people were injured.

The judge also said the probation report expressed concern over another shooting at 1OAK during VMA weekend last August. Again, Chris was on stage and several people were shot, including Suge Knight.

And the judge said Chris left the county for San Jose without getting the court's permission, which is a violation of his probation.

As for why the shootings are an issue, they were raised in the probation report. The judge noted so far there's no evidence Chris was criminally involved, but the probation officer says, "There is also concern that when he performs or attends at some of his public events, people will get shot or seriously injured."

The probation officer also notes Chris has been arrested twice while on probation -- once for assault in DC and also for throwing a rock at his mom's car in rehab. And the officer notes Chris was "making comments about knives and guns during a group [rehab] meeting."

The probation officer -- who thinks Chris is focusing too much on his career rather than community service and rehabilitation -- recommends to the judge that Chris serve time. The officer says the singer has shown "a pattern of making choices that are counterproductive."

The judge will hold a formal hearing March 20. If hizzoner determines Chris "willfully" violated probation, he could be in big trouble. The violations are felonies, which means prison is on the line.

Chris Brown has made community service his full-time job for the last 6 weeks ... and his goal is to get it all done within weeks.

We've learned, since November 13, Chris has been doing physical labor 6 hours a day, 5 days a week to complete his 1,000 hours by the next court hearing in mid-January. There have been a few weeks where work has gotten in the way, but the drill is 6/5.

Chris' community service in the Rihanna case requires hard labor, and we're told he's working at a facility approved by the Probation Dept., painting, cleaning, trash removal, moving furniture ... stuff like that.

Last Friday Chris put his 6 hours in and then jumped on a plane to Jacksonville, FL where he performed that night at the Memorial Arena. He then flew to Columbia, South Carolina for a Saturday show, then on to Birmingham, AL for a Sunday performance. He took a private jet back to L.A. for hard labor Monday.

And we're told ... he hasn't complained or acted up.

Our sources say he's on track to tell the judge during the next court appearance ... mission accomplished.

Chris Brown may be necking with Rihanna again ... with his current girlfriend right by his side.

CB and Karrueche Tran were all over L.A. Tuesday promoting his new album. Chris has been wearing a necklace with an angel on it ... that looks exactly like Rihanna's.

Our photog asked Chris if the necklace was a gift from Rihanna ... but he was mum.

But sources close to Chris tell us the necklace has no connection to Rihanna. We're guessing Chris knew exactly what he was doing -- getting people to talk about him just as his album drops.

Smart.

8:47 A.M. PDT -- We're told the game was a Roc Nation charity event. Rihanna was scheduled to be there and Chris was supposedly a "surprise appearance."

Rihanna is ridiculous ... and thirsty like Moses wandering the desert.

She showed up in the front row at a charity basketball game Thursday ... eyes trained on ex-BF Chris Brown.

Now that she's with Drake again and not Chris Brown again ... you'd think she wouldn't fuel the fire. But then again, who are we kidding?

It's a special kind of insult to Karrueche ... who's back with Chris after being repeatedly humiliated by whatever continues to transpire between him and Rihanna.

Your move Karrueche.

Chris Brown -- NOT KARRUECHE -- is the one who did the breaking up, because she was a crass opportunist ... so say people in Chris' camp.

Sources closely connected with the singer tell TMZ ... Chris is shocked Karrueche's people leaked a story that she dumped him, allegedly because of a never-ending obsession with Rihanna and refusal to act like an adult.

But Chris' people tell us ... he found out she was texting and sending photos to other guys while they were together. He was also furious she did interviews for her clothing line and talked about their relationship.

In a word ... Chris decided she was an "opportunist" and dumped her.

Chris Brown played the Rihanna card one too many times with Karrueche Tran ... we've learned Karrueche has not only broken up with him ... for safe measure she changed her number.

Our sources say Karrueche exploded when Chris recently "liked" 2 fan photos on Instagram of Rihanna and him together.

But Rihanna was only a small part of Karrueche's problems with Chris. We're told she was unhappy for a long time ... as sources put it, because "Chris acts immature, like a child." She thinks he's ruining his life by spending more time partying than making music.

Chris' reaction to the break up has been breathtaking. He went to St. Tropez this week and took a very good friend of Karrueche's along for the ride. And he made a point to be photographed with her ... making sure Karrueche would see it.

Karrueche's reaction was not jealousy. We're told she's changed her phone number ... specifically so Chris couldn't contact her.

Boy ... it takes guts.

Hip hop producer Mally Mall played a key role in settling Drake and Chris Brown's longstanding feud ... because he brought them together at his house in Las Vegas.

When we caught up with Mally in L.A. ... he said "the past is the past" for Breezy and Drizzy, and that Rihanna's name never came up during their recording sessions in Mally's home studio.

They've come a long way from 2 years ago when they destroyed W.i.P. Nightclub in New York in an all-out brawl over RiRi -- but Mally says ... "We squashed the beef."

Mally -- who's new release "Mally's World" drops next month -- did have one comment about Rihanna "acting like a jump off."

New beef?

The curious new friendship between Chris Brown and Drake has NOTHING to do with Rihanna or brotherly love ... we've learned it's a cold, business decision about making millions.

Chris and Drake -- whose posses literally destroyed W.i.P. nightclub in NYC in 2012 over a Rihanna beef -- have decided they can actually make more money together than separately ... this according to sources working closely with the 2 performers.

They're now in the studio ... laying tracks down for Chris' new album. We're told Drake will perform with Chris on some of the songs and he'll also be the producer.

There's a bonus for Chris -- by working with Drake he'll be able to continue being affiliated with Young Money and that keeps the door open to collaborations with Lil Wayne and Nicki Minaj. As a matter of fact, we know Tyga -- also part of Y.M. -- was in the studio with Drake and Chris on Thursday.

Two other reasons Chris and Drake think working together will sell more albums:

-- People will pick the lyrics apart, trying to figure out if they are talking about Rihanna ... the woman who they both slept with and the catalyst for the W.i.P. brawl.

-- Everyone wants to hear who sounds better -- Chris or Drake.

Mortal enemies Chris Brown and Drake proved their long-standing ... and sometimes violent Rihanna beef may finally be over for good -- and they might be sealing the truce with new music.

Drake posted a pic last night of himself and Chris in a recording studio -- and Breezy looks like he's LOVING whatever music they're listening to at the moment. Could a post RiRi collabo be coming?

There were rumors the feud was over, but this is the first visual evidence. Pretty amazing ... considering the beef exploded 2 years ago in a massive brawl at W.i.P. nightclub in NYC. Chris and a bodyguard were left bloodied, and NBA star Tony Parker suffered a serious eye injury.

The peace has been brewing since last April when we spotted Chris in a club dancing to "Started From the Bottom" -- but, yeah ... they've come a really long way.

Chris Brown looked haggard and tired in court Thursday afternoon during a hearing in the Rihanna case.

TMZ broke the story ... Brown has been behind bars since March 14, when the judge threw him in jail after getting kicked out of rehab for the second time.

Brown looked defeated as the judge ruled he will remain in jail -- at least until the next hearing May 9 ... when both sides will come back to court and say whether they could strike a deal over the probation violation.

Brown had to endure a LONG flight from L.A. to D.C. and back ... so he could attend his assault trial in the nation's capital. That trial has been postponed.

Chris Brown will rot behind bars until June -- at the very least -- because the singer's latest bid for freedom was just DENIED.

Brown -- who was jailed last month after getting booted from rehab -- was flown to D.C. and promptly jailed as he awaited trial in his assault case.

The trial was supposed to start today ... but it was just postponed until June.

Brown asked the judge in the Rihanna beating case to release him, but the judge just shut him down.

Translation: Brown will soon be flown back to L.A. -- where he'll remain in jail until June ... at the very least. It looks like he'll be flown back to D.C. on Con air ... a trip way worse than economy.

The stakes are high ... if Brown is convicted in D.C. ... the judge in the Rihanna case could violate his probation and sentence Brown to four years in PRISON.

Chris Brown just checked into the "Four Seasons" of jails ... and good news/bad news -- he gets to shower as much as he wants!

Chris arrived in Washington, D.C. after a 5-day trek from California courtesy of Con-Air.

An administrator at Northern Neck Regional Jail in Virginia confirms Chris is currently an inmate -- and he's quick to add Chris isn't getting special treatment.

Chris has been placed in limited general population with no restrictions -- meaning he gets to enjoy all the amenities of the facility, including:

-- Daily showers
-- TV
-- Library
-- Telephone
-- Exercise
-- Meals in the cafeteria

It beats L.A. jail by a country mile ... where he was locked down in solitary 23 hours a day.

The downside ... besides group showers -- he circulates among the other inmates.

Hopefully there's no Rihanna fans in the slammer.

Chris Brown learned a lesson this week ... what it must have been like travelling across the country by stagecoach ... because four days into his journey he is still not in Washington D.C.

TMZ broke the story ... Brown was taken from his L.A. County jail cell Thursday by U.S. Marshals for the cross country trip.

We're told he made several stops along the way and typically when a prisoner lands he is taken to a nearby jail to wait for the next available flight.

Brown's lawyer Mark Geragos will be in a D.C. courtroom Monday trying to get his client's case dismissed on grounds of grand jury misconduct. It's unclear if Chris will make it to the hearing.

Brown will stand trial April 17th for allegedly assaulting a man outside a D.C. hotel.

A typical commercial flight from L.A. to D.C. takes 4 hours and 40 minutes.