Bug 2281022

1. Please describe the problem:

There is a new kernel option in town, `CONFIG_KASAN_HW_TAGS`, making use of aarch64's MTE/TBI to power KASAN. The performance impact is super-duper-low, and it'll likely uncover memory corruption issues. The main drawback is that, well, it'll find memory corruption issues, but this can be mitigated by using `kasan.fault=report`, so that the issues will be reported and the kernel won't be panic'ed. Another mitigating factor is that statistically ~nobody is running fedora on aarch64, except via the asahi linux remix, so the number of affected users should be low-ish.

It's currently enabled by default on android: https://source.android.com/docs/security/test/memory-safety/arm-mte#mte-in-kernel


2. What is the Version-Release number of the kernel:

N/A

3. Did it work previously in Fedora? If so, what kernel version did the issue
   *first* appear?  Old kernels are available for download at
   https://koji.fedoraproject.org/koji/packageinfo?packageID=8 :

No

4. Can you reproduce this issue? If so, please provide the steps to reproduce
   the issue below:

Compile the kernel with the proper option, notice that it doesn't break anything, doesn't tank the performances, and results in some "memory corruption in kernel-land, oh no :<" message from time to time.

5. Does this problem occur with the latest Rawhide kernel? To install the
   Rawhide kernel, run ``sudo dnf install fedora-repos-rawhide`` followed by
   ``sudo dnf update --enablerepo=rawhide kernel``:

N/A

6. Are you running any modules that not shipped with directly Fedora's kernel?:

N/A

7. Please attach the kernel logs. You can get the complete kernel log
   for a boot with ``journalctl --no-hostname -k > dmesg.txt``. If the
   issue occurred on a previous boot, use the journalctl ``-b`` flag.

N/A

Reproducible: Always