Greetings, 0day kernel testing robot got the below dmesg and the first bad commit is https://github.com/digitalocean/linux-coresched coresched commit 27d21449d31b065ebaf1be593f2874096f48eaef Author: Peter Zijlstra <peterz(a)infradead.org&gt; AuthorDate: Mon Feb 18 17:56:25 2019 +0100 Commit: Vineeth Remanan Pillai <vpillai(a)digitalocean.com&gt; CommitDate: Tue May 21 13:55:24 2019 +0000 sched: Add task_struct pointer to sched_class::set_curr_task In preparation of further separating pick_next_task() and set_curr_task() we have to pass the actual task into it, while there, rename the thing to better pair with put_prev_task(). Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org&gt; 1b3e82fe5a sched/{rt,deadline}: Fix set_next_task vs pick_next_task 27d21449d3 sched: Add task_struct pointer to sched_class::set_curr_task 8d75dc6554 prio_less refactoring +------------------------------------------------------+------------+------------+------------+ | | 1b3e82fe5a | 27d21449d3 | 8d75dc6554 | +------------------------------------------------------+------------+------------+------------+ | boot_successes | 41 | 0 | 2 | | boot_failures | 1 | 10 | 11 | | BUG:soft_lockup-CPU##stuck_for#s | 1 | 1 | | | EIP:prep_new_page | 1 | | | | Kernel_panic-not_syncing:softlockup:hung_tasks | 1 | 1 | | | WARNING:at_kernel/sched/sched.h:#pick_next_task_fair | 0 | 9 | | | EIP:pick_next_task_fair | 0 | 9 | | | WARNING:at_kernel/sched/sched.h:#put_prev_task | 0 | 9 | 11 | | EIP:put_prev_task | 0 | 9 | 11 | | EIP:__drm_mm_interval_first | 0 | 1 | | +------------------------------------------------------+------------+------------+------------+ If you fix the issue, kindly add following tag Reported-by: kernel test robot <lkp(a)intel.com&gt; Please press Enter to activate this console. [ 69.039734] random: ubusd: uninitialized urandom read (4 bytes read) [ 69.043732] random: ubusd: uninitialized urandom read (4 bytes read) [ 69.044626] random: ubusd: uninitialized urandom read (4 bytes read) [ 70.024617] Unregister pv shared memory for cpu 1 [ 70.027227] WARNING: CPU: 1 PID: 15 at kernel/sched/sched.h:1719 pick_next_task_fair+0x33/0x3b5 [ 70.028193] CPU: 1 PID: 15 Comm: migration/1 Not tainted 5.2.0-rc1-00103-g27d2144 #1 [ 70.028938] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 70.029704] EIP: pick_next_task_fair+0x33/0x3b5 [ 70.030161] Code: 56 53 89 c3 83 ec 2c 89 55 d8 89 4d dc b8 40 e0 05 82 89 45 c8 83 7b 6c 00 0f 84 13 01 00 00 8b 45 d8 3b 83 44 05 00 00 74 02 <0f> 0b 8d 43 60 89 45 e8 8b 45 d8 8b 48 50 89 c2 89 d8 ff 51 1c 8d [ 70.031910] EAX: 81d0d800 EBX: 9f81c040 ECX: 9f27becc EDX: 81d0d800 [ 70.032507] ESI: 81d0d800 EDI: 8186f120 EBP: 9f27be94 ESP: 9f27be5c [ 70.033117] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010087 [ 70.033775] CR0: 80050033 CR2: 77f6053c CR3: 1d511000 CR4: 001406d0 [ 70.034403] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 70.035000] DR6: fffe0ff0 DR7: 00000400 [ 70.035365] Call Trace: [ 70.035600] ? update_irq_load_avg+0x2df/0x2ff [ 70.036007] ? pick_next_task+0x4c/0x74 [ 70.036386] ? sched_cpu_dying+0x92/0x1ab [ 70.036838] ? sched_cpu_starting+0x2e/0x2e [ 70.037349] ? cpuhp_invoke_callback+0xab/0x215 [ 70.037903] ? sched_cpu_starting+0x2e/0x2e [ 70.038429] ? preempt_count_sub+0x14/0x1e [ 70.038924] ? take_cpu_down+0x56/0x7f [ 70.039381] ? multi_cpu_stop+0x72/0xd6 [ 70.039858] ? cpumask_test_cpu+0x15/0x15 [ 70.040364] ? cpu_stopper_thread+0x78/0xd6 [ 70.040806] ? smpboot_thread_fn+0x1df/0x1f3 [ 70.041337] ? kthread+0xd8/0xda [ 70.041648] ? smpboot_destroy_threads+0x67/0x67 [ 70.042186] ? __kthread_create_on_node+0x125/0x125 [ 70.042707] ? ret_from_fork+0x1e/0x30 [ 70.043122] ---[ end trace 2c1f854fe6492c7f ]--- [ 70.043604] WARNING: CPU: 1 PID: 15 at kernel/sched/sched.h:1719 put_prev_task+0x1a/0x24 # HH:MM RESULT GOOD BAD GOOD_BUT_DIRTY DIRTY_NOT_BAD git bisect start 2fa2a748b230dca1b0664a6ed78068bb86e002aa f49aa1de98363b6c5fba4637678d6b0ba3d18065 -- git bisect bad b0655ef051a4d1cea71effa1258285ee770916ac # 23:47 B 1 17 0 0 sched/fair: Export newidle_balance() git bisect good 4ef3eb925e2bd3eb4bcf7484bd3804d5b526b3c3 # 23:48 G 18 0 0 0 stop_machine: Fix stop_cpus_in_progress ordering git bisect good 811221193b809099f9c4d6cf37b85981c9e7a635 # 23:48 G 11 0 0 0 sched: Wrap rq::lock access git bisect good 1b3e82fe5a4fc1e07d8b71d785ac808238365429 # 23:48 G 11 0 0 1 sched/{rt,deadline}: Fix set_next_task vs pick_next_task git bisect bad 27d21449d31b065ebaf1be593f2874096f48eaef # 00:17 B 1 5 1 1 sched: Add task_struct pointer to sched_class::set_curr_task # first bad commit: [27d21449d31b065ebaf1be593f2874096f48eaef] sched: Add task_struct pointer to sched_class::set_curr_task git bisect good 1b3e82fe5a4fc1e07d8b71d785ac808238365429 # 00:35 G 31 0 0 1 sched/{rt,deadline}: Fix set_next_task vs pick_next_task # extra tests on HEAD of digitalocean-linux-coresched/coresched git bisect bad 2fa2a748b230dca1b0664a6ed78068bb86e002aa # 00:35 B 0 21 40 0 sched: Debug bits... # extra tests on tree/branch digitalocean-linux-coresched/coresched git bisect bad 8d75dc65548b1dbccb9e3480c5130b9a6c7e626f # 00:38 B 0 11 36 0 prio_less refactoring --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/lkp Intel Corporation