Yauhen, in the meanwhile, could you please try to reproduce the bug withlibx11-6-dbg and libx11-xcb1-dbg packages installed and show the crash backtraces again?
At least we would know what procedure in libx11 crashed and what exact reasoning XCB gave.
You can freely remove the packages mentioned above afterwards. -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org