Greetings, 0day kernel testing robot got the below dmesg and the first bad commit is https://github.com/rgushchin/linux.git freezer.10 commit 653a05850aad543a2bf389d94dcb084deced4c3f Author: Roman Gushchin <guro(a)fb.com&gt; AuthorDate: Tue Mar 12 17:47:00 2019 -0700 Commit: Roman Gushchin <guro(a)fb.com&gt; CommitDate: Thu Apr 4 13:49:13 2019 -0700 cgroup: add tracing points for cgroup v2 freezer Add cgroup:cgroup_freeze and cgroup:cgroup_unfreeze events, which are using the existing cgroup tracing infrastructure. Add the cgroup_event event class, which is similar to the cgroup class, but contains an additional integer field to store a new value (the level field is dropped). Also add two tracing events: cgroup_notify_populated and cgroup_notify_frozen, which are raised in a generic way using the TRACE_CGROUP_PATH() macro. This allows to trace cgroup state transitions and is generally helpful for debugging the cgroup freezer code. Signed-off-by: Roman Gushchin <guro(a)fb.com&gt; 07343392e6 cgroup: make TRACE_CGROUP_PATH irq-safe 653a05850a cgroup: add tracing points for cgroup v2 freezer 2602261b06 signal: unconditionally leave the frozen state in ptrace_stop() +-------------------------------+------------+------------+------------+ | | 07343392e6 | 653a05850a | 2602261b06 | +-------------------------------+------------+------------+------------+ | boot_successes | 32 | 0 | 0 | | boot_failures | 0 | 11 | 13 | | BUG:kernel_hang_in_boot_stage | 0 | 11 | 13 | +-------------------------------+------------+------------+------------+ If you fix the issue, kindly add following tag Reported-by: kernel test robot <lkp(a)intel.com&gt; [ 0.018728] MTRR fixed ranges enabled: [ 0.019134] 00000-9FFFF write-back [ 0.019524] A0000-BFFFF uncachable [ 0.019910] C0000-FFFFF write-protect [ 0.020322] MTRR variable ranges enabled: BUG: kernel hang in boot stage # HH:MM RESULT GOOD BAD GOOD_BUT_DIRTY DIRTY_NOT_BAD git bisect start 452a7c538947314b18972f8bf2e89e80bd53738c 145f47c7381d43c789cbad55d4dbfd28fc6c46a4 -- git bisect good 871de1567ddd038c391721d208750910bc2196c3 # 21:06 G 10 0 3 3 kselftests: cgroup: add freezer controller self-tests git bisect bad 7988328e154fd522084baa65f63e83da106d11c9 # 21:30 B 0 1 16 0 REMOVE ME: cover letter git bisect bad 653a05850aad543a2bf389d94dcb084deced4c3f # 22:02 B 0 1 16 0 cgroup: add tracing points for cgroup v2 freezer git bisect good 07343392e61dab5281881e195d863cfe5f9e093c # 23:03 G 10 0 2 2 cgroup: make TRACE_CGROUP_PATH irq-safe # first bad commit: [653a05850aad543a2bf389d94dcb084deced4c3f] cgroup: add tracing points for cgroup v2 freezer git bisect good 07343392e61dab5281881e195d863cfe5f9e093c # 00:10 G 31 0 1 3 cgroup: make TRACE_CGROUP_PATH irq-safe # extra tests with debug options git bisect good 653a05850aad543a2bf389d94dcb084deced4c3f # 02:44 G 10 0 1 1 cgroup: add tracing points for cgroup v2 freezer # extra tests on HEAD of rgushchin/freezer.10 git bisect bad 452a7c538947314b18972f8bf2e89e80bd53738c # 02:44 B 0 19 43 0 signal: don't always leave task frozen after ptrace_stop() # extra tests on tree/branch rgushchin/freezer.10 git bisect bad 2602261b066a06f6884057d2cd7369951768b9ed # 03:49 B 0 1 18 2 signal: unconditionally leave the frozen state in ptrace_stop() # extra tests with first bad commit reverted git bisect good 91d402863442f2e5cf3ce3c166f3569889497eea # 05:37 G 10 0 0 0 Revert "cgroup: add tracing points for cgroup v2 freezer" --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/lkp Intel Corporation