On Thu, 9 Jul 2020 at 13:55, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Thu, Jul 9, 2020 at 7:28 AM Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> 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/ksm/ksm05.c > https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/mem/thp/thp01.c > > 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/testrun/1324990/suite/ltp-mm-tests/test/ksm02/log --- [ 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
