Bug 206519
| Summary: | [amdgpu] kernel NULL pointer dereference on shutdown when CONFIG_DRM_AMD_DC_HDCP=y | ||
|---|---|---|---|
| Product: | Drivers | Reporter: | Shlomo (shlomo) |
| Component: | Video(DRI - non Intel) | Assignee: | drivers_video-dri |
| Status: | RESOLVED CODE_FIX | ||
| Severity: | normal | CC: | alexdeucher |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 5.5.1.arch1-1, 5.5.3-arch1-1 | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: |
shutdown screen photo
dmesg after boot possible fix |
||
Created attachment 287355 [details]
dmesg after boot
Can you bisect? The bug first occurs in Arch Linux 5.5.arch1-1, which set CONFIG_DRM_AMD_DC_HDCP=y [1]. Arch Linux 5.4.15.arch1-1 is good. Arch Linux 5.4.15.arch1-1 with CONFIG_DRM_AMD_DC_HDCP=y set (and no other changes) is bad. Arch Linux 5.5.arch1-1 (and later) is bad. (CONFIG_DRM_AMD_DC_HDCP=y is set) Testing the most recent Arch Linux kernel shows the same: Arch Linux 5.5.3.arch1 is bad. Arch Linux 5.5.3.arch1 with CONFIG_DRM_AMD_DC_HDCP unset is good. This means that this bug was triggered by changes to the config, not kernel changes, so I don't know if this is a regression or not. [1] https://git.archlinux.org/svntogit/packages.git/commit/trunk?h=packages/linux&id=019514c4cdff26addfd49db8a78a857cb03994d9 I bisected the bug. The first bad commit is 96a3b32e67236f547cc8acd69d5a3cef125b2295 (drm/amd/display: only enable HDCP for DCN+) with ea268870d6f548d0661e896e9746673210c1fa79 (drm/amd/display: Add hdcp to Kconfig) cherry-picked on top of it. (The previous commit da3fd7ac0bcf372cc57117bdfcd725cca7ef975a with ea268870d6f548d0661e896e9746673210c1fa79 cherry-picked on top of it is good.) The call trace for this bug is the same as I posted above. Created attachment 287487 [details]
possible fix
I think this patch should fix it.
Yes, this fixes the bug. I applied your patch over linux v5.5, but I first had to modify it so it would apply: - drm_connector_attach_content_protection_property(&aconnector->base, true); + drm_connector_attach_content_protection_property(&aconnector->base, false); Confirmed fixed on Arch linux 5.6.2-arch1-2. Thanks. |
Created attachment 287353 [details] shutdown screen photo When I try to power off my machine, it shows the usual shutdown messages and the screens turn off, but the machine is still powered on. The virtual console shows a kernel NULL pointer dereference at address 0. I run Arch Linux. The bug occurs even if I never run X. I can turn on the machine and immediately try to shut it down, and the same bug still occurs. This bug occurred since I upgraded linux 5.4.15.arch1-1 to 5.5.1.arch1-1. I now run linux 5.5.3.arch1-1 and the bug still exists. My graphics card is Gigabyte Radeon RX VEGA 56 GAMING OC 8G, connected to six monitors. A photo of the screen at shutdown is attached. I think these are the relevant lines for this bug: BUG: kernel NULL pointer dereference, address: 0 [...] RIP: 0010:queue_work_on+0x17/0x40 Code: fd ff ff 44 89 e0 5d 41 5c c3 [...] Call Trace: handle_hpd_rx_irq+0x26e/0x320 [amdgpu] ? _raw_spin_unlock_irq+0x1d/0x30 dm_irq_work_func+0x49/0x60 [amdgpu] process_one_work+0x1e1/0x3d0 [...]