runners: Add option to install custom kernel on Fedora

Allow installing a custom kernel version from the Fedora experimental
kernel repos onto the github runners.  This is useful for testing if
ZFS works against a newer kernel.

Fedora has a number of repos with experimental kernel packages. This
PR allows installs from kernels in these repos:

@kernel-vanilla/stable
@kernel-vanilla/mainline
(https://fedoraproject.org/wiki/Kernel_Vanilla_Repositories)

You will need to manually kick of a github runner to test with a custom
kernel version.  To do that, go to the github actions tab under
'zfs-qemu' and click the drop-down for 'run workflow'.  In there you
will see a text box to specify the version (like '6.14').  The scripts
will do their best to match the version to the newest matching version
that the repos support (since they're may be multiple nightly versions
of, say, '6.14').  A full list of kernel versions can be seen in the
dependency stage output if you kick off a manual run.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tino Reichardt <milky-zfs@mcmilk.de>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes #17156
(cherry picked from commit b55256e5bb)

.github/workflows/scripts/qemu-3-deps-vm.sh

@@ -4,6 +4,8 @@
 # 3) install dependencies for compiling and loading
 #
 # $1: OS name (like 'fedora41')
+# $2: (optional) Experimental Fedora kernel version, like "6.14" to
+#     install instead of Fedora defaults.
 ######################################################################
 
 set -eu
@@ -95,6 +97,25 @@ function tumbleweed() {
   echo "##[endgroup]"
 }
 
+# $1: Kernel version to install (like '6.14rc7')
+function install_fedora_experimental_kernel {
+
+  our_version="$1"
+  sudo dnf -y copr enable @kernel-vanilla/stable
+  sudo dnf -y copr enable @kernel-vanilla/mainline
+  all="$(sudo dnf list --showduplicates kernel-*)"
+  echo "Available versions:"
+  echo "$all"
+
+  # You can have a bunch of minor variants of the version we want '6.14'.
+  # Pick the newest variant (sorted by version number).
+  specific_version=$(echo "$all" | grep $our_version | awk '{print $2}' | sort -V | tail -n 1)
+  list="$(echo "$all" | grep $specific_version | grep -Ev 'kernel-rt|kernel-selftests|kernel-debuginfo' | sed 's/.x86_64//g' | awk '{print $1"-"$2}')"
+  sudo dnf install -y $list
+  sudo dnf -y copr disable @kernel-vanilla/stable
+  sudo dnf -y copr disable @kernel-vanilla/mainline
+}
+
 # Install dependencies
 case "$1" in
   almalinux8)
@@ -133,6 +154,11 @@ case "$1" in
 
     # Fedora 42+ moves /usr/bin/script from 'util-linux' to 'util-linux-script'
     sudo dnf install -y util-linux-script || true
+
+    # Optional: Install an experimental kernel ($2 = kernel version)
+    if [ -n "${2:-}" ] ; then
+      install_fedora_experimental_kernel "$2"
+    fi
     ;;
   freebsd*)
     freebsd

.github/workflows/scripts/qemu-3-deps.sh

@@ -3,12 +3,25 @@
 #    script on it.
 #
 # $1: OS name (like 'fedora41')
+# $2: (optional) Experimental kernel version to install on fedora,
+#     like "6.14".
 ######################################################################
 
 .github/workflows/scripts/qemu-wait-for-vm.sh vm0
+
+# SPECIAL CASE:
+#
+# If the user passed in an experimental kernel version to test on Fedora,
+# we need to update the kernel version in zfs's META file to allow the
+# build to happen.  We update our local copy of META here, since we know
+# it will be rsync'd up in the next step.
+if [ -n "${2:-}" ] ; then
+  sed -i -E 's/Linux-Maximum: .+/Linux-Maximum: 99.99/g' META
+fi
+
 scp .github/workflows/scripts/qemu-3-deps-vm.sh zfs@vm0:qemu-3-deps-vm.sh
 PID=`pidof /usr/bin/qemu-system-x86_64`
-ssh zfs@vm0 '$HOME/qemu-3-deps-vm.sh' $1
+ssh zfs@vm0 '$HOME/qemu-3-deps-vm.sh' "$@"
 # wait for poweroff to succeed
 tail --pid=$PID -f /dev/null
 sleep 5 # avoid this: "error: Domain is already active"

.github/workflows/zfs-qemu.yml

@@ -15,6 +15,11 @@ on:
         required: false
         default: false
         description: 'Test on CentOS 10 stream'
+      fedora_kernel_ver:
+        type: string
+        required: false
+        default: ""
+        description: "(optional) Experimental kernel version to install on Fedora (like '6.14' or '6.13.3-0.rc3')"
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
@@ -48,7 +53,15 @@ jobs:
           else
             os_selection="$FULL_OS"
           fi
-          os_json=$(echo ${os_selection} | jq -c)
+
+          if [ ${{ github.event.inputs.fedora_kernel_ver }} != "" ] ; then
+              # They specified a custom kernel version for Fedora.  Use only
+              # Fedora runners.
+              os_json=$(echo ${os_selection} | jq -c '[.[] | select(startswith("fedora"))]')
+          else
+              # Normal case
+              os_json=$(echo ${os_selection} | jq -c)
+          fi
 
           # Add optional runners
           if [ "${{ github.event.inputs.include_stream9 }}" == 'true' ]; then
@@ -92,7 +105,7 @@ jobs:
 
     - name: Install dependencies
       timeout-minutes: 20
-      run: .github/workflows/scripts/qemu-3-deps.sh ${{ matrix.os }}
+      run: .github/workflows/scripts/qemu-3-deps.sh ${{ matrix.os }} ${{ github.event.inputs.fedora_kernel_ver }}
 
     - name: Build modules
       timeout-minutes: 30