On Thu, 9 Jul 2020 at 13:55, Arnd Bergmann arnd@arndb.de wrote:
On Thu, Jul 9, 2020 at 7:28 AM Naresh Kamboju naresh.kamboju@linaro.org wrote:
While running LTP mm test suite on i386 or qemu_i386 this kernel warning has been noticed from stable 5.4 to stable 5.7 branches and mainline 5.8.0-rc4 and linux next.
Are you able to correlate this with any particular test case in LTP, or does it happen for random processes?
In the log you linked to, it happens once for ksm05.c and multiple times for thp01.c, sources here:
https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/mem/k... https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/mem/t...
Is it always these tests that trigger the warning, or sometimes others?
These two test cases are causing this warning multiple times on i386.
When you say it happens with linux-5.4 stable, does that mean you don't see it with older versions? What is the last known working version?
I do not notice on stable-4.19 and below versions. Sorry i did not get the known working commit id or version.
It started happening from stable-rc 5.0 first release. I have evidence [1] showing it on 5.0.1
I also see that you give the virtual machine 16GB of RAM, but as you are running a 32-bit kernel without PAE, only 2.3GB end up being available, and some other LTP tests in the log run out of memory.
You could check if the behavior changes if you give the kernel less memory, e.g. 768MB (lowmem only), or enable CONFIG_X86_PAE to let it use the entire 16GB.
Warning is still happening after enabling PAE config. But the oom-killer messages are gone. Thank you.
CONFIG_HIGHMEM=y CONFIG_X86_PAE=y
full test log oom-killer messages are gone and kernel warning is still there, https://lkft.validation.linaro.org/scheduler/job/1552606#L10357
build location: https://builds.tuxbuild.com/puilcMcGVwzFMN5fDUhY4g/
[1] https://qa-reports.linaro.org/lkft/linux-stable-rc-5.0-oe/build/v5.0.1/testr...
--- [ 775.646689] WARNING: CPU: 3 PID: 10858 at /srv/oe/build/tmp-lkft-glibc/work-shared/intel-core2-32/kernel-source/mm/mremap.c:211 move_page_tables+0x553/0x570 [ 775.647006] Modules linked in: fuse [ 775.647006] CPU: 3 PID: 10858 Comm: true Not tainted 5.0.1 #1 [ 775.647006] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 775.647006] EIP: move_page_tables+0x553/0x570
- Naresh