Fix kernel panic caused by legacy devices on AMD platforms
Bug #1936682 reported by
Kai-Heng Feng
This bug affects 1 person
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| HWE Next |
Fix Released
|
Undecided
|
Unassigned | ||
| linux (Ubuntu) |
Fix Released
|
High
|
Unassigned | ||
| Focal |
Won't Fix
|
Undecided
|
Unassigned | ||
| Hirsute |
Fix Released
|
High
|
Unassigned | ||
| Impish |
Fix Released
|
High
|
Unassigned | ||
| linux-oem-5.10 (Ubuntu) |
Invalid
|
Undecided
|
Unassigned | ||
| Focal |
Fix Released
|
High
|
Unassigned | ||
| Hirsute |
Invalid
|
Undecided
|
Unassigned | ||
| Impish |
Invalid
|
Undecided
|
Unassigned | ||
| linux-oem-5.13 (Ubuntu) |
Invalid
|
Undecided
|
Unassigned | ||
| Focal |
Fix Released
|
High
|
Unassigned | ||
| Hirsute |
Invalid
|
Undecided
|
Unassigned | ||
| Impish |
Invalid
|
Undecided
|
Unassigned | ||
Bug Description
[Impact]
When a legacy device is only 32bit DMA capable and it's in the same
IOMMU group with iommu_v2 capable devices, the device in question will
be forced to use identity mapping and triggers kernel panic on DMA
operation because it can't do 64bit DMA.
[Fix]
Keep swiotlb enabled so legacy devices can do 64bit DMA. This is also
how Intel and ARM64 platforms deal with legacy devices.
[Test]
Boot an affected system. Kernel panic in Realtek WiFi driver's probe
routine.
After the patch is applied, the system can work normally.
[Where problems could occur]
The default swiotlb uses 64MB memory, so if the system doesn't have any
legacy device, there are 64MB ram less for the system to use.
CVE References
| Changed in linux (Ubuntu Focal): | |
| status: | New → Won't Fix |
| Changed in linux (Ubuntu Hirsute): | |
| status: | New → Confirmed |
| Changed in linux (Ubuntu Impish): | |
| status: | New → Confirmed |
| Changed in linux (Ubuntu Hirsute): | |
| importance: | Undecided → High |
| Changed in linux (Ubuntu Impish): | |
| importance: | Undecided → High |
| Changed in linux-oem-5.10 (Ubuntu Focal): | |
| status: | New → Confirmed |
| importance: | Undecided → High |
| Changed in linux-oem-5.10 (Ubuntu Hirsute): | |
| status: | New → Invalid |
| Changed in linux-oem-5.10 (Ubuntu Impish): | |
| status: | New → Invalid |
| Changed in linux-oem-5.13 (Ubuntu Focal): | |
| importance: | Undecided → High |
| status: | New → Confirmed |
| Changed in linux-oem-5.13 (Ubuntu Hirsute): | |
| status: | New → Invalid |
| Changed in linux-oem-5.13 (Ubuntu Impish): | |
| status: | New → Invalid |
| tags: | added: oem-priority originate-from-1933798 stella |
| Changed in linux-oem-5.10 (Ubuntu Focal): | |
| status: | Confirmed → Fix Committed |
| Changed in linux-oem-5.13 (Ubuntu Focal): | |
| status: | Confirmed → Fix Committed |
Revision history for this message
| Ubuntu Kernel Bot (ubuntu-kernel-bot) wrote | #1 |
| tags: | added: verification-needed-focal |
| tags: |
added: verification-done-focal removed: verification-needed-focal |
Revision history for this message
| Launchpad Janitor (janitor) wrote | #2 |
| Changed in linux-oem-5.10 (Ubuntu Focal): | |
| status: | Fix Committed → Fix Released |
Revision history for this message
| Launchpad Janitor (janitor) wrote | #3 |
Download full text (5.6 KiB)
| Changed in linux-oem-5.13 (Ubuntu Focal): | |
| status: | Fix Committed → Fix Released |
| Changed in linux (Ubuntu Hirsute): | |
| status: | Confirmed → Fix Committed |
Revision history for this message
| Ubuntu Kernel Bot (ubuntu-kernel-bot) wrote | #4 |
| tags: | added: verification-needed-hirsute |
| tags: |
added: verification-done-hirsute removed: verification-needed-hirsute |
Revision history for this message
| Launchpad Janitor (janitor) wrote | #5 |
| Changed in linux (Ubuntu Impish): | |
| status: | Confirmed → Fix Released |
Revision history for this message
| Launchpad Janitor (janitor) wrote | #6 |
Download full text (68.6 KiB)
| Changed in linux (Ubuntu Hirsute): | |
| status: | Fix Committed → Fix Released |
| Changed in hwe-next: | |
| status: | New → Fix Released |
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This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.
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