FYI, we noticed the following commit (built with gcc-7): commit: 7ac2b00f8fd7070459aab5a9addee36eefc13b3f ("mm/swap: Access struct pagevec remotely") https://git.kernel.org/cgit/linux/kernel/git/bigeasy/staging.git mm_swap in testcase: ltp with following parameters: disk: 1HDD test: mm-01 test-description: The LTP testsuite contains a collection of tools for testing the Linux kernel and related features. test-url: http://linux-test-project.github.io/ on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 4G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): <<<test_start>>> tag=ksm03_1 stime=1557012455 cmdline="ksm03 -u 128" contacts="" analysis=exit <<<test_output>>> tst_test.c:1096: INFO: Timeout per run is 0h 05m 00s mem.c:411: INFO: wait for all children to stop. mem.c:377: INFO: child 2 stops. mem.c:377: INFO: child 1 stops. mem.c:377: INFO: child 0 stops. mem.c:484: INFO: KSM merging... mem.c:423: INFO: resume all children. mem.c:411: INFO: wait for all children to stop. mem.c:333: INFO: child 2 continues... mem.c:337: INFO: child 2 allocates 128 MB filled with 'a' mem.c:333: INFO: child 1 continues... mem.c:337: INFO: child 1 allocates 128 MB filled with 'a' mem.c:333: INFO: child 0 continues... mem.c:337: INFO: child 0 allocates 128 MB filled with 'c' mem.c:389: INFO: child 1 stops. mem.c:389: INFO: child 0 stops. mem.c:389: INFO: child 2 stops. ksm_helper.c:48: INFO: ksm daemon takes 2s to run two full scans mem.c:261: INFO: check! mem.c:254: PASS: run is 1. mem.c:254: PASS: pages_shared is 2. mem.c:254: PASS: pages_sharing is 98302. mem.c:254: PASS: pages_volatile is 0. mem.c:254: PASS: pages_unshared is 0. mem.c:254: PASS: sleep_millisecs is 0. mem.c:254: PASS: pages_to_scan is 98304. mem.c:423: INFO: resume all children. mem.c:411: INFO: wait for all children to stop. mem.c:295: INFO: child 0 verifies memory content. mem.c:295: INFO: child 2 verifies memory content. mem.c:295: INFO: child 1 verifies memory content. mem.c:333: INFO: child 0 continues... mem.c:337: INFO: child 0 allocates 128 MB filled with 'c' mem.c:333: INFO: child 1 continues... mem.c:337: INFO: child 1 allocates 128 MB filled with 'b' mem.c:333: INFO: child 2 continues... mem.c:337: INFO: child 2 allocates 128 MB filled with 'a' mem.c:389: INFO: child 0 stops. mem.c:389: INFO: child 1 stops. mem.c:389: INFO: child 2 stops. ksm_helper.c:48: INFO: ksm daemon takes 1s to run two full scans mem.c:261: INFO: check! mem.c:254: PASS: run is 1. mem.c:254: PASS: pages_shared is 3. mem.c:252: FAIL: pages_sharing is not 98301 but 98293. mem.c:252: FAIL: pages_volatile is not 0 but 8. mem.c:254: PASS: pages_unshared is 0. mem.c:254: PASS: sleep_millisecs is 0. mem.c:254: PASS: pages_to_scan is 98304. mem.c:423: INFO: resume all children. mem.c:411: INFO: wait for all children to stop. mem.c:295: INFO: child 0 verifies memory content. mem.c:295: INFO: child 2 verifies memory content. mem.c:295: INFO: child 1 verifies memory content. mem.c:333: INFO: child 0 continues... mem.c:333: INFO: child 2 continues... mem.c:337: INFO: child 0 allocates 128 MB filled with 'd' mem.c:337: INFO: child 2 allocates 128 MB filled with 'd' mem.c:333: INFO: child 1 continues... mem.c:337: INFO: child 1 allocates 128 MB filled with 'd' mem.c:389: INFO: child 2 stops. mem.c:389: INFO: child 0 stops. mem.c:389: INFO: child 1 stops. ksm_helper.c:48: INFO: ksm daemon takes 1s to run two full scans mem.c:261: INFO: check! mem.c:254: PASS: run is 1. mem.c:254: PASS: pages_shared is 1. mem.c:252: FAIL: pages_sharing is not 98303 but 98300. mem.c:252: FAIL: pages_volatile is not 0 but 3. mem.c:254: PASS: pages_unshared is 0. mem.c:254: PASS: sleep_millisecs is 0. mem.c:254: PASS: pages_to_scan is 98304. mem.c:423: INFO: resume all children. mem.c:411: INFO: wait for all children to stop. mem.c:295: INFO: child 0 verifies memory content. mem.c:295: INFO: child 2 verifies memory content. mem.c:295: INFO: child 1 verifies memory content. mem.c:333: INFO: child 2 continues... mem.c:337: INFO: child 2 allocates 128 MB filled with 'd' mem.c:333: INFO: child 0 continues... mem.c:337: INFO: child 0 allocates 128 MB filled with 'd' mem.c:333: INFO: child 1 continues... mem.c:342: INFO: child 1 allocates 128 MB filled with 'd' except one page with 'e' mem.c:389: INFO: child 1 stops. mem.c:389: INFO: child 0 stops. mem.c:389: INFO: child 2 stops. ksm_helper.c:48: INFO: ksm daemon takes 1s to run two full scans mem.c:261: INFO: check! mem.c:254: PASS: run is 1. mem.c:254: PASS: pages_shared is 1. mem.c:254: PASS: pages_sharing is 98302. mem.c:254: PASS: pages_volatile is 0. mem.c:254: PASS: pages_unshared is 1. mem.c:254: PASS: sleep_millisecs is 0. mem.c:254: PASS: pages_to_scan is 98304. mem.c:507: INFO: KSM unmerging... mem.c:423: INFO: resume all children. mem.c:261: INFO: check! mem.c:254: PASS: run is 2. mem.c:254: PASS: pages_shared is 0. mem.c:254: PASS: pages_sharing is 0. mem.c:254: PASS: pages_volatile is 0. mem.c:254: PASS: pages_unshared is 0. mem.c:254: PASS: sleep_millisecs is 0. mem.c:254: PASS: pages_to_scan is 98304. mem.c:513: INFO: stop KSM. mem.c:261: INFO: check! mem.c:254: PASS: run is 0. mem.c:254: PASS: pages_shared is 0. mem.c:254: PASS: pages_sharing is 0. mem.c:254: PASS: pages_volatile is 0. mem.c:254: PASS: pages_unshared is 0. mem.c:254: PASS: sleep_millisecs is 0. mem.c:254: PASS: pages_to_scan is 98304. mem.c:295: INFO: child 0 verifies memory content. mem.c:295: INFO: child 1 verifies memory content. mem.c:295: INFO: child 1 verifies memory content. mem.c:295: INFO: child 2 verifies memory content. mem.c:404: INFO: child 0 finished. mem.c:404: INFO: child 1 finished. mem.c:404: INFO: child 2 finished. Summary: passed 38 failed 4 skipped 0 warnings 0 <<<execution_status>>> initiation_status="ok" duration=8 termination_type=exited termination_id=1 corefile=no cutime=180 cstime=172 <<<test_end>>> If you fix the issue, kindly add following tag Reported-by: kernel test robot <rong.a.chen(a)intel.com&gt; To reproduce: # build kernel cd linux cp config-5.1.0-rc6-00003-g7ac2b00 .config make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 olddefconfig make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 prepare make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 modules_prepare make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 SHELL=/bin/bash make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 bzImage git clone https://github.com/intel/lkp-tests.git cd lkp-tests find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz bin/lkp qemu -k <bzImage> -m modules.cgz job-script # job-script is attached in this email Thanks, Rong Chen