Disable ftrace of sbi functions
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux-riscv (Ubuntu) |
Fix Released
|
Undecided
|
Unassigned | ||
Hirsute |
Fix Released
|
Undecided
|
Unassigned | ||
linux-riscv-5.11 (Ubuntu) |
Invalid
|
Undecided
|
Unassigned | ||
Focal |
Fix Released
|
High
|
Unassigned |
Bug Description
[Impact]
* A kernel build can fail to boot with Oops and illegal instruction as seen at https:/
* One cannot frace functions, used in frace setup. On RISC-V these are sbi calls to firmware from sbi.c which were not excluded for tracing. Similar functions on other arches are already excluded.
* Previously we have identified one call that was racing and causing failure to boot and marked it for notrace. But the upstream solution is to disable all functions in sbi.c which was implemented in v5.12 but did not make it to stable/earlier trees.
* Note that this failure to boot is racy, meaning some lucky builds of kernel always boot or always fail, as was observed on Unmatched.
[Test Plan]
* Kernel should boot on baremetal Unmatched, Unleashed, and qemu
[Where problems could occur]
* This patch disables profiling and tracing of sbi.c function calls. Previously it was possible to trace them, somewhat, either successfully in a racy manner or to cause a kernel panic.
CVE References
affects: | linux-riscv-5.11 (Ubuntu) → linux-riscv (Ubuntu) |
no longer affects: | linux-riscv-5.11 (Ubuntu Hirsute) |
Changed in linux-riscv-5.11 (Ubuntu): | |
status: | New → Invalid |
Changed in linux-riscv-5.11 (Ubuntu Focal): | |
status: | New → Confirmed |
Changed in linux-riscv (Ubuntu Hirsute): | |
status: | New → Confirmed |
no longer affects: | linux-riscv (Ubuntu Focal) |
Changed in linux-riscv (Ubuntu): | |
status: | New → Fix Released |
Changed in linux-riscv-5.11 (Ubuntu Focal): | |
importance: | Undecided → High |
Changed in linux-riscv-5.11 (Ubuntu Focal): | |
status: | Confirmed → Fix Committed |
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- needed- hirsute' to 'verification- done-hirsute' . If the problem still exists, change the tag 'verification- needed- hirsute' to 'verification- failed- hirsute' .
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.
See https:/ /wiki.ubuntu. com/Testing/ EnableProposed for documentation how to enable and use -proposed. Thank you!