In FC42, when I run "./luo_multi_session"
# ./luo_multi_session # [STAGE 1] Starting pre-kexec setup for multi-session test... # [STAGE 1] Creating state file for next stage (2)... # [STAGE 1] Creating empty sessions 'multi-test-empty-1' and 'multi-test-empty-2'... # [STAGE 1] Creating session 'multi-test-files-1' with one memfd... # [STAGE 1] Creating session 'multi-test-files-2' with two memfds... # [STAGE 1] Executing kexec...
Then the system hang. And via virt-viewer, a calltrace will appear.
The call trace is in the attachment.
Yanjun.Zhu
在 2025/11/10 7:26, Pasha Tatashin 写道:
On Mon, Nov 10, 2025 at 8:16 AM Pratyush Yadav pratyush@kernel.org wrote:
On Sun, Nov 09 2025, Zhu Yanjun wrote:
在 2025/11/8 10:13, Pasha Tatashin 写道:
On Fri, Nov 7, 2025 at 6:36 PM Yanjun.Zhu yanjun.zhu@linux.dev wrote:
On 11/7/25 4:02 AM, Pasha Tatashin wrote:
On Fri, Nov 7, 2025 at 7:00 AM Pasha Tatashin pasha.tatashin@soleen.com wrote: >> Hi, Pasha >> >> In our previous discussion, we talked about counting the number of times >> the kernel is rebooted via kexec. At that time, you suggested adding a >> variable in debugfs to keep track of this count. >> However, since debugfs is now optional, where would be an appropriate >> place to store this variable? > It is an optional config and can still be enabled if the live update > reboot number value needs to be accessed through debugfs. However, > given that debugfs does not guarantee a stable interface, tooling > should not be built to require these interfaces. > > In the WIP LUO [1] I have, I pr_info() the live update number during > boot and also store it in the incoming LUO FDT tree, which can also be > accessed through this optional debugfs interface. > > The pr_info message appears like this during boot: > [ 0.000000] luo: Retrieved live update data, liveupdate number: 17 > > Pasha Forgot to add link to WIP LUOv5: [1] https://github.com/soleen/linux/tree/luo/v5rc04
Thanks a lot. I’ve carefully read this commit: https://github.com/soleen/linux/commit/60205b9a95c319dc9965f119303a1d83f0ff0....
To be honest, I’d like to run some tests with who/luo, including the selftest for kho/luo. Could you please share the steps with me?
If the testing steps have already been documented somewhere, could you please share the link?
Currently the test performs in-kernel tests for FLB data, it creates a number of FLB for every registered LUO file-handler, which at the moment is only memfd.
It works together with any of the kexec based live update tests. In v5, I introduce two tests: luo_kexec_simple luo_multi_session
For example, with luo_multi_session:
Hi, Pasha
I enabled "CONFIG_LIVEUPDATE=y"
# ./luo_multi_session 1..0 # SKIP Failed to open /dev/liveupdate. Is the luo module loaded?
# ls /dev/liveupdate ls: cannot access '/dev/liveupdate': No such file or directory
# grep "LIVEUPDATE" -inrHI /boot/config-`uname -r` /boot/config-next-20251107-luo+:349:CONFIG_LIVEUPDATE=y /boot/config-next-20251107-luo+:11985:CONFIG_LIVEUPDATE_TEST=y
I made tests on FC42. But /dev/liveupdate is missing.
You need to add liveupdate=1 to your kernel cmdline to enable LUO and get /dev/liveupdate.
+1, kernel parameters require: kho=1 liveupdate=1
Pasha, your LUO series doesn't add the liveupdate parameter to kernel-parameters.txt. I think it should be done in the next version to this parameter is discoverable.
Yeah, that is missing, I will update that in a standalone patch, or in a next version.
Thanks, Pasha
