Greetings, 0day kernel testing robot got the below dmesg and the first bad commit is https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/debug commit 4157505f1ba490082cc7fda9593e4ae821a0a778 Author: Peter Zijlstra <peterz(a)infradead.org&gt; AuthorDate: Mon Oct 3 16:53:49 2016 +0200 Commit: Peter Zijlstra <peterz(a)infradead.org&gt; CommitDate: Mon Dec 12 16:42:17 2016 +0100 sched: Add WARNING for multiple update_rq_clock() calls Now that we have no missing calls, add a warning to find multiple calls. By having only a single update_rq_clock() call per rq-lock section, the section appears 'atomic' wrt time. Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org&gt; +-------------------------------------------------+------------+------------+------------+ | | 14f2dc16de | 4157505f1b | 072c2c3b3d | +-------------------------------------------------+------------+------------+------------+ | boot_successes | 64 | 0 | 0 | | boot_failures | 0 | 26 | 21 | | WARNING:at_kernel/sched/core.c:#update_rq_clock | 0 | 26 | 21 | +-------------------------------------------------+------------+------------+------------+ [ 0.000000] hpet clockevent registered [ 0.000000] tsc: Detected 2693.508 MHz processor [ 0.000000] ------------[ cut here ]------------ [ 0.000000] WARNING: CPU: 0 PID: 0 at kernel/sched/core.c:109 update_rq_clock+0x6b/0xf9 [ 0.000000] rq->clock_update_flags & RQCF_UPDATED [ 0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.0-00055-g4157505 #1 [ 0.000000] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014 [ 0.000000] ffff88001d403d88 ffffffff81417d20 ffff88001d403dd8 ffffffff8220f662 [ 0.000000] ffff88001d403dc8 ffffffff8107b82b 0000006d1d403e40 ffff88001d5d72c0 [ 0.000000] 0000000000000000 ffffffff82417500 ffff880000092200 ffff88001d403f34 [ 0.000000] Call Trace: [ 0.000000] <IRQ> [ 0.000000] [<ffffffff81417d20>] dump_stack+0x61/0x7e [ 0.000000] [<ffffffff8107b82b>] __warn+0xb3/0xce [ 0.000000] [<ffffffff8107b88c>] warn_slowpath_fmt+0x46/0x4e [ 0.000000] [<ffffffff810990b4>] update_rq_clock+0x6b/0xf9 [ 0.000000] [<ffffffff8109c31a>] scheduler_tick+0x3f/0x88 [ 0.000000] [<ffffffff810ccb80>] update_process_times+0x42/0x4f [ 0.000000] [<ffffffff810d761e>] tick_periodic+0x9b/0x9d [ 0.000000] [<ffffffff810d7640>] tick_handle_periodic+0x20/0x61 [ 0.000000] [<ffffffff810213bf>] timer_interrupt+0x10/0x17 [ 0.000000] [<ffffffff810bf25c>] __handle_irq_event_percpu+0x35/0xd7 [ 0.000000] [<ffffffff810bf319>] handle_irq_event_percpu+0x1b/0x46 [ 0.000000] [<ffffffff810bf377>] handle_irq_event+0x33/0x51 [ 0.000000] [<ffffffff810c1f34>] handle_level_irq+0x96/0xc9 [ 0.000000] [<ffffffff81020f7f>] handle_irq+0xfa/0x106 [ 0.000000] [<ffffffff81020923>] do_IRQ+0x46/0xc2 [ 0.000000] [<ffffffff81cc737f>] common_interrupt+0x7f/0x7f [ 0.000000] <EOI> [ 0.000000] [<ffffffff815386ad>] ? serial8250_console_write+0x1be/0x1d5 [ 0.000000] [<ffffffff8103baa4>] ? native_restore_fl+0x6/0x8 [ 0.000000] [<ffffffff810bd40f>] console_unlock+0x4ba/0x4ea [ 0.000000] [<ffffffff810bd833>] vprintk_emit+0x3f4/0x44d [ 0.000000] [<ffffffff810bd9ee>] vprintk_default+0x18/0x1a [ 0.000000] [<ffffffff8110732a>] printk+0x43/0x4b [ 0.000000] [<ffffffff827617c7>] tsc_init+0xbc/0x292 [ 0.000000] [<ffffffff8275db92>] ? setup_default_timer_irq+0x1e/0x20 [ 0.000000] [<ffffffff8275db72>] x86_late_time_init+0xf/0x11 [ 0.000000] [<ffffffff82752f16>] start_kernel+0x3b6/0x465 [ 0.000000] [<ffffffff82752120>] ? early_idt_handler_array+0x120/0x120 [ 0.000000] [<ffffffff827522d6>] x86_64_start_reservations+0x2a/0x2c [ 0.000000] [<ffffffff827523be>] x86_64_start_kernel+0xe6/0xf3 [ 0.000000] ---[ end trace 0000000000000000 ]--- [ 1.255306] Calibrating delay loop (skipped) preset value.. 5387.01 BogoMIPS (lpj=10774032) git bisect start 072c2c3b3de7190fee772271e11b1d2003a5c8c5 69973b830859bc6529a7a0468ba0d80ee5117826 -- git bisect bad d2b552c260ca9ab9184f2c6284d588cca638eb29 # 02:08 0- 3 Merge 'peterz-queue/debug/tmp' into devel-catchup-201612130113 git bisect bad 6cd6b5277b809e62136d5756180c10a69520a9a9 # 02:32 0- 1 Merge 'peterz-queue/locking/refcount' into devel-catchup-201612130113 git bisect good 7874c77cfa1f7d2fbd6e98560015f5e473f29cc9 # 03:40 20+ 0 Merge 'peterz-queue/sched-core-for-linus' into devel-catchup-201612130113 git bisect bad fb4f94353e00050c928521c620c910899472696c # 04:47 0- 1 Merge 'peterz-queue/sched/debug' into devel-catchup-201612130113 git bisect good 08118b281b2052030a69fb727c9e8d7a8d29e2d4 # 08:25 21+ 0 sched: Add missing update_rq_clock() call for task_hot(). git bisect bad 08499deaff2b6e18fbcf5783b3f57f93d24d2c1d # 08:33 0- 5 sched: Add rq->lock wrappers git bisect good 14f2dc16de55f0f111db6d345bac494bd9b79b85 # 08:55 20+ 0 Merge branch 'sched/core' git bisect bad 4157505f1ba490082cc7fda9593e4ae821a0a778 # 09:20 0- 3 sched: Add WARNING for multiple update_rq_clock() calls # first bad commit: [4157505f1ba490082cc7fda9593e4ae821a0a778] sched: Add WARNING for multiple update_rq_clock() calls git bisect good 14f2dc16de55f0f111db6d345bac494bd9b79b85 # 11:44 60+ 0 Merge branch 'sched/core' # extra tests with CONFIG_DEBUG_INFO_REDUCED git bisect bad 4157505f1ba490082cc7fda9593e4ae821a0a778 # 11:50 0- 3 sched: Add WARNING for multiple update_rq_clock() calls # extra tests on HEAD of linux-devel/devel-catchup-201612130113 git bisect bad 072c2c3b3de7190fee772271e11b1d2003a5c8c5 # 11:50 0- 21 0day head guard for 'devel-catchup-201612130113' # extra tests on tree/branch peterz-queue/sched/debug git bisect bad 4537f174812aa16caea2b7a3734d5c74b34f7733 # 12:47 0- 1 sched: Avoid double update_rq_clock() # extra tests with first bad commit reverted git bisect good e7ce5afb287ac99cb442c254b106f2584ee3e683 # 15:01 60+ 0 Revert "sched: Add WARNING for multiple update_rq_clock() calls" # extra tests on tree/branch linus/master git bisect good e7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba # 15:53 64+ 8 Merge tag 'docs-4.10' of git://git.lwn.net/linux # extra tests on tree/branch linux-next/master git bisect good b11a0cf861d7de4cd5f7596e02cfdb6ee09ea1f4 # 16:06 60+ 1 Add linux-next specific files for 20161212 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/lkp Intel Corporation