Since some weeks now, I’ve got a freeze when I use firefox / youtube on AMD / Radeon.
A priori the freeze is triggered by the youtube video. I think I was able to reproduce this using vlc too.
How can I get valuable information to report this problem ?
I was not able to get something via journalctl.
OK, forget about this message 
I managed to fix the freeze.
I had a very old .mozilla directory / firefox profile. I removed the directory to let firefox create a new one and it fixed the problem.
Hmmm, no, it just happened a little bit later.
I switch to a consle via ctrl+alt+f3 and logged as a root user and done a dmesg.
The kernel oops log was there. a Radeon driver crash …
nov. 18 10:34:41 localhost.localdomain kernel: ---[ end trace 0000000000000000 ]---
nov. 18 10:34:41 localhost.localdomain kernel: </TASK>
nov. 18 10:34:41 localhost.localdomain kernel: R13: 0000000000000000 R14: 00007fab8adfbee8 R15: 00007fab8adfbf00
nov. 18 10:34:41 localhost.localdomain kernel: R10: 00007fab8ac05fa8 R11: 0000000000000246 R12: 00007fab8adf69e0
nov. 18 10:34:41 localhost.localdomain kernel: RBP: 0000000000000000 R08: fffffffffffffc78 R09: 00007fab8ae01b20
nov. 18 10:34:41 localhost.localdomain kernel: RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
nov. 18 10:34:41 localhost.localdomain kernel: RAX: ffffffffffffffda RBX: 00007fab8adf69e0 RCX: 00007fab8ad187f1
nov. 18 10:34:41 localhost.localdomain kernel: RSP: 002b:00007ffde2313ab8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
nov. 18 10:34:41 localhost.localdomain kernel: Code: Unable to access opcode bytes at RIP 0x7fab8ad187c7.
nov. 18 10:34:41 localhost.localdomain kernel: RIP: 0033:0x7fab8ad187f1
nov. 18 10:34:41 localhost.localdomain kernel: entry_SYSCALL_64_after_hwframe+0x63/0xcd
nov. 18 10:34:41 localhost.localdomain kernel: do_syscall_64+0x3b/0xc0
nov. 18 10:34:41 localhost.localdomain kernel: __x64_sys_exit_group+0x14/0x20
nov. 18 10:34:41 localhost.localdomain kernel: do_group_exit+0x2d/0x90
nov. 18 10:34:41 localhost.localdomain kernel: do_exit+0x325/0xa10
nov. 18 10:34:41 localhost.localdomain kernel: task_work_run+0x5c/0xa0
nov. 18 10:34:41 localhost.localdomain kernel: __fput+0xdd/0x250
nov. 18 10:34:41 localhost.localdomain kernel: __dentry_kill+0xf8/0x170
nov. 18 10:34:41 localhost.localdomain kernel: dma_buf_release+0x3a/0xa0
nov. 18 10:34:41 localhost.localdomain kernel: drm_gem_dmabuf_release+0x36/0x50 [drm]
nov. 18 10:34:41 localhost.localdomain kernel: radeon_gem_object_free+0x30/0x60 [radeon]
nov. 18 10:34:41 localhost.localdomain kernel: radeon_bo_unref+0x1a/0x30 [radeon]
nov. 18 10:34:41 localhost.localdomain kernel: ? fsnotify_grab_connector+0x49/0x90
nov. 18 10:34:41 localhost.localdomain kernel: ? call_rcu+0xd6/0x760
nov. 18 10:34:41 localhost.localdomain kernel: ? __inode_wait_for_writeback+0x7e/0xf0
nov. 18 10:34:41 localhost.localdomain kernel: ? xa_load+0x70/0xb0
nov. 18 10:34:41 localhost.localdomain kernel: <TASK>
nov. 18 10:34:41 localhost.localdomain kernel: Call Trace:
nov. 18 10:34:41 localhost.localdomain kernel: CR2: 00007fab8a604734 CR3: 00000001032a4000 CR4: 00000000000406e0
nov. 18 10:34:41 localhost.localdomain kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
nov. 18 10:34:41 localhost.localdomain kernel: FS: 00007fab8ae0ff00(0000) GS:ffff888233d80000(0000) knlGS:0000000000000000
nov. 18 10:34:41 localhost.localdomain kernel: R13: ffff8881001a0de0 R14: ffff888112202240 R15: ffff8881511947c0
nov. 18 10:34:41 localhost.localdomain kernel: R10: 0000000000000000 R11: 0000000000000000 R12: ffff888128f42478
nov. 18 10:34:41 localhost.localdomain kernel: RBP: ffff88823d4446f0 R08: ffff888128f425c8 R09: 0000000000000000
nov. 18 10:34:41 localhost.localdomain kernel: RDX: 0000000000000003 RSI: 0000000000000000 RDI: ffff888128f425c8
nov. 18 10:34:41 localhost.localdomain kernel: RAX: 0000000000000000 RBX: ffff888128f425c8 RCX: 0000000000000000
nov. 18 10:34:41 localhost.localdomain kernel: RSP: 0018:ffffc90001407d98 EFLAGS: 00010206
nov. 18 10:34:41 localhost.localdomain kernel: Code: 00 e8 9f 90 3f e1 48 8b 43 e8 eb a8 be 03 00 00 00 e8 df 4e 17 e1 e9 fc fd ff ff e8 25 66 3f e1 e9 f2 fd ff ff 48 89 e8 eb 8a <0f> 0b 48 83 7b 20 00 0f 84 33 fd ff ff 0f 0b e9 2c fd >
nov. 18 10:34:41 localhost.localdomain kernel: RIP: 0010:ttm_bo_release+0x305/0x320 [ttm]
nov. 18 10:34:41 localhost.localdomain kernel: Hardware name: HP 450-a121nf/2B29, BIOS A0.11 01/15/2016
nov. 18 10:34:41 localhost.localdomain kernel: CPU: 3 PID: 920 Comm: Xorg Tainted: G W 6.0.7-lqx1.fc35.x86_64 #1
nov. 18 10:34:41 localhost.localdomain kernel: snd_seq_device snd_pcm mc libarc4 snd_timer hp_wmi sparse_keymap snd joydev mousedev irqbypass platform_profile pktcdvd rfkill pcspkr i2c_piix4 soundcore wmi_bmof fam15h_power k10temp efi>
nov. 18 10:34:41 localhost.localdomain kernel: Modules linked in: snd_seq_dummy snd_hrtimer xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT xt_tcpudp nf_nat_tftp nft_objref nf_conntrack_tftp bridge stp llc af_packet nft_fib_inet nft_>
nov. 18 10:34:41 localhost.localdomain kernel: WARNING: CPU: 3 PID: 920 at drivers/gpu/drm/ttm/ttm_bo.c:356 ttm_bo_release+0x305/0x320 [ttm]
nov. 18 10:34:41 localhost.localdomain kernel: ------------[ cut here ]------------
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
nov. 18 10:34:41 localhost.localdomain kernel: [drm:radeon_gem_va_ioctl [radeon]] *ERROR* Couldn't update BO_VA (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: failed to sync rings (-22)
nov. 18 10:34:41 localhost.localdomain kernel: radeon 0000:00:01.0: Syncing to a disabled ring!
This happened on the standard Fedora kernel 6.0.8.
I opened a ticket on redhat / fedora bug tracker and sent a mail to kernel-rt-users bug I’ve got no news for a week now.
What is the best strategy to report such a problem ?