GDS force mitigation re-enabled in 6.10 (and 6.11) causing crashes
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
In Progress
|
Medium
|
Philip Cox |
Bug Description
The (supposedly unintended) re-enabling of GDS force migration in the Ubuntu 6.10 kernels causes the AVX instruction to be disabled on older CPUs which have no available microcode update. This causes various programs to crash due to the unconditional use of AVX in libgnutls.so, libxul.so, etc.
Typically "traps" of "invalid opcode" will be seen in dmesg output along with the initial notice:
[ 0.121833] GDS: Microcode update needed! Disabling AVX as mitigation.
[ 0.121835] GDS: Mitigation: AVX disabled, no microcode
When GDS force mitigation appeared in the kernel, with default "y", it created a lot of issues like these and Ubuntu quickly patched all their kernels, this from the 6.2.0-28.
==========
```
diff -u linux-6.
--- linux-6.
+++ linux-6.
@@ -1,3 +1,13 @@
+linux (6.2.0-31.31) lunar; urgency=medium
+
+ * lunar/linux: 6.2.0-31.31 -proposed tracker (LP: #2031146)
+
+ * libgnutls report "trap invalid opcode" when trying to install packages over
+ https (LP: #2031093)
+ - [Config]: disable CONFIG_
+
+ -- Thadeu Lima de Souza Cascardo <email address hidden> Mon, 14 Aug 2023 08:29:52 -0300
+
linux (6.2.0-28.29) lunar; urgency=medium
* lunar/linux: 6.2.0-28.29 -proposed tracker (LP: #2030547)
diff -u linux-6.
--- linux-6.
+++ linux-6.
@@ -4992,7 +4992,7 @@
CONFIG_GCC_VERSION policy<{'amd64': '120200', 'arm64': '120200', 'armhf': '120200', 'ppc64el': '120200', 'riscv64': '120200', 's390x': '120200'}>
CONFIG_GCOV_KERNEL policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'ppc64el': 'n', 'riscv64': 'n', 's390x': 'n'}>
CONFIG_GDB_SCRIPTS policy<{'amd64': 'y', 'arm64': 'y', 'armhf': 'y', 'ppc64el': 'y', 'riscv64': 'y', 's390x': 'y'}>
-CONFIG_
+CONFIG_
CONFIG_
CONFIG_
CONFIG_
```
==========
In upstream 6.9 the option was renamed from CONFIG_
==========
```
CONFIG_GDB_SCRIPTS policy<{'amd64': 'y', 'arm64': 'y', 'armhf': 'y', 'ppc64el': 'y', 'riscv64': 'y', 's390x': 'y'}>
-CONFIG_
CONFIG_
...
CONFIG_
+CONFIG_
+CONFIG_
+CONFIG_
+CONFIG_
```
==========
I am sure this was an oversight, and that the old option was simply dropped because it didn't exist any longer, without thinking of it being renamed (among a lot of other renames).
description: | updated |
description: | updated |
description: | updated |
description: | updated |
summary: |
- GDS force mitigation re-enabled in 6.10 causing crashes + GDS force mitigation re-enabled in 6.10 (and 6.11) causing crashes |
Hello Tormod, thank you for taking the time to open this bug report.
I just checked the latest 6.10 ubuntu kernel tree, and this seems to be resolved when the tree rebased to 6.10rc1.
Here is the current state of the kernel config:
https:/ /git.launchpad. net/~ubuntu- kernel/ ubuntu/ +source/ linux/+ git/oracular/ tree/debian. master/ config/ annotations? h=Ubuntu- 6.10.0- 20.20
and on line 8134 you can see the expected config option.
And this is the change that added it:
https:/ /git.launchpad. net/~ubuntu- kernel/ ubuntu/ +source/ linux/+ git/oracular/ commit/ ?h=master- next&id= 05a2ea830dd81bb 94bc7bd22755a90 d685b4d4bf