Hi, the problem is not Debian specific. I tried to build latest upstream kernel commit 43c4f67c966deb1478dc9acbf66ab547287d530f (49 commits after 4.9-rc7) and the problem is more or less the same:
zito@bobek:~/radeon/4.9.0rc7$ fgrep -m1 -h BUG radeon-kms-messages??.txt [ 15.730673] BUG: unable to handle kernel NULL pointer dereference at 000000000000006c [ 44.148004] NMI watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [run-parts:379] [ 48.148004] NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [systemd-fstab-g:445] [ 44.144003] NMI watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [(d-logind):400] [ 44.152004] NMI watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [upstart:387] [ 48.148013] NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [kworker/1:2:51] [ 15.316493] BUG: unable to handle kernel NULL pointer dereference at 000000000000006c [ 48.152014] NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [smartd:452] Circa 1 of 10 boots the problem not perform, but the problem is during shutdown in that case (shutdown hangs). I tried also older Debian kernels. The version 4.7.x - very similar, version 4.6.x - the score of successfull boot up is a bit bigger, but problem is there too. My subjective view is the problem (probably some very old kernel bug) is more propagating in newner kernel versions. -- Zito
