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From: "Yanjun.Zhu" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 783DC80004 X-Stat-Signature: 91uzq5frzg6jhnjmpkptrdaxq1fezczu X-Rspam-User: X-HE-Tag: 1762998106-637372 X-HE-Meta: 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 dL98EjEM vPbqxm+r1mfXpRa1rTLYQ6toyDzjf4vBNNurWuSnngK3H4iOZhzFMkLDpv/0E8seVqLiV0Bpy0H7XAN1lGiV3zRmj+V2jdgrxLzYpwrRmawA1+ROxq8N8KC1wQ5kStxKnGjn/CqPJs+r+thwWHXzU6+IKf7MH42Fu2ZpP3aePoRvA8JVV5iGj+37a99GDdMb+uO80Bod6R56h7JGHOVXlgzm2yOMF0K+hXUh2hPnm/4DLv6KeySrYv06r/iYpWtFb6Tg2j5QXSZUmXc6SXrqfArCftt8JXBoTWuBzw7CmO6NSdnAzsZ4e68mubEIDOvCOSpPKs97+mDLal9QNx2ub4x/ZCw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 11/11/25 7:26 AM, Pasha Tatashin wrote: > On Mon, Nov 10, 2025 at 11:11 PM Zhu Yanjun wrote: >> 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. > Looks like mountroot fails, are you passing the same kernel parameters > as the during cold boot? > i.e. kexec -l -s --reuse-cmdline --initrd=[initramfs] [kernel] Thanks a lot. It can work now.  The logs are as below: " # [STAGE 2] Starting post-kexec verification... # [STAGE 2] Retrieving all sessions... # [STAGE 2] Verifying contents of session 'multi-test-files-1'... # [STAGE 2] Verifying contents of session 'multi-test-files-2'... # [STAGE 2] Test data verified successfully. # [STAGE 2] Finalizing all test sessions... # [STAGE 2] Finalizing state session... # --- MULTI-SESSION KEXEC TEST PASSED --- " Yanjun.Zhu > > Pasha > >> 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 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 wrote: >>>>>>> On 11/7/25 4:02 AM, Pasha Tatashin wrote: >>>>>>>> On Fri, Nov 7, 2025 at 7:00 AM Pasha Tatashin 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/60205b9a95c319dc9965f119303a1d83f0ff08fa. >>>>>>> >>>>>>> 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 >> -- >> Best Regards, >> Yanjun.Zhu