Greetings, 0day kernel testing robot got the below dmesg and the first bad commit is git://anongit.freedesktop.org/drm-intel topic/core-for-CI commit 398ceb91b81505e7138eecdac870a59e85661671 Author: Daniel Vetter <daniel.vetter(a)ffwll.ch&gt; AuthorDate: Tue Mar 20 17:02:58 2018 +0100 Commit: Daniel Vetter <daniel.vetter(a)ffwll.ch&gt; CommitDate: Mon Jun 25 18:07:12 2018 +0200 RFC: debugobjects: capture stack traces at _init() time Sometimes it's really easy to know which object has gone boom and where the offending code is, and sometimes it's really hard. One case we're trying to hunt down is when module unload catches a live debug object, with a module with lots of them. Capture a full stack trace from debug_object_init() and dump it when there's a problem. FIXME: Should we have a separate Kconfig knob for the backtraces, they're quite expensive? Atm I'm just selecting it for the general debug object stuff. v2: Drop the locks for gathering&storing the backtrace. This is required because depot_save_stack can call free_pages (to drop it's preallocation), which can call debug_check_no_obj_freed, which will recurse into the db->lock spinlocks. Cc: Philippe Ombredanne <pombredanne(a)nexb.com&gt; Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org&gt; Cc: Thomas Gleixner <tglx(a)linutronix.de&gt; Cc: Kate Stewart <kstewart(a)linuxfoundation.org&gt; Cc: Daniel Vetter <daniel.vetter(a)ffwll.ch&gt; Cc: Waiman Long <longman(a)redhat.com&gt; Acked-by-for-CI-testing: Chris Wilson <chris(a)chris-wilson.co.uk&gt; Signed-off-by: Daniel Vetter <daniel.vetter(a)intel.com&gt; Link: https://patchwork.freedesktop.org/patch/msgid/20180320160258.11381-1-dani... ebaef7b2f7 kernel/panic: Repeat the line and caller information at the end of the OOPS 398ceb91b8 RFC: debugobjects: capture stack traces at _init() time b1ee8b0d94 Documentation: e100: Fix docs build error +-------------------------------------------------------+------------+------------+------------+ | | ebaef7b2f7 | 398ceb91b8 | b1ee8b0d94 | +-------------------------------------------------------+------------+------------+------------+ | boot_successes | 23 | 0 | 0 | | boot_failures | 20 | 15 | 13 | | WARNING:possible_circular_locking_dependency_detected | 20 | | | | BUG:kernel_hang_in_boot_stage | 0 | 15 | 13 | +-------------------------------------------------------+------------+------------+------------+ kernel_total_size: 0x0000000003aaf000 trampoline_32bit: 0x000000000009d000 Decompressing Linux... Parsing ELF... done. Booting the kernel. BUG: kernel hang in boot stage Linux version 4.18.0-rc2-00007-g398ceb9 #1 Command line: root=/dev/ram0 hung_task_panic=1 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 net.ifnames=0 printk.devkmsg=on panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 drbd.minor_count=8 systemd.log_level=err ignore_loglevel console=tty0 earlyprintk=ttyS0,115200 console=ttyS0,115200 vga=normal rw link=/kbuild-tests/run-queue/yocto-lkp-nhm-dp2/x86_64-randconfig-s3-06300434/linux-devel:devel-catchup-201806300333:398ceb91b81505e7138eecdac870a59e85661671:bisect-linux-32/.vmlinuz-398ceb91b81505e7138eecdac870a59e85661671-20180630111015-8:yocto-lkp-nhm-dp2-10 branch=linux-devel/devel-catchup-201806300333 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-s3-06300434/gcc-7/398ceb91b81505e7138eecdac870a59e85661671/vmlinuz-4.18.0-rc2-00007-g398ceb9 drbd.minor_count=8 rcuperf.shutdown=0 # HH:MM RESULT GOOD BAD GOOD_BUT_DIRTY DIRTY_NOT_BAD git bisect start 691ef198391e10a174dedbea19727b45d453ad47 7daf201d7fe8334e2d2364d4e8ed3394ec9af819 -- git bisect good 3b03431ffcdfa7ae2bbb7c3f1c71766f66849d83 # 06:06 G 10 0 5 5 Merge 'lpieralisi-pci/pci/controller-fixes' into devel-catchup-201806300333 git bisect bad 6d16a4c44349091e57d96550facbb6a7d597bd5c # 06:26 B 0 1 14 0 Merge 'linux-review/Philipp-Zabel/media-coda-mark-CODA960-firmware-version-2-1-9-as-supported/20180629-220504' into devel-catchup-201806300333 git bisect bad b65c314ab490a111080b5cd07e9aa024a439a9b2 # 06:48 B 0 2 15 0 Merge 'ath6kl/master-pending' into devel-catchup-201806300333 git bisect bad 0c633bf0e5915066d9e83ad4a68ce428b4e9621a # 07:20 B 0 1 14 0 Merge 'cifs/for-next' into devel-catchup-201806300333 git bisect good 5b6f5648fe62afa5b3fcab8ae9bdd8ae0d6ae742 # 07:40 G 10 0 2 2 Merge 'jpirko-mlxsw/petrm_erspan_lag_fixes' into devel-catchup-201806300333 git bisect bad a0275c5d4ac6da625e02a5722994c321a681977c # 08:07 B 0 5 18 0 Merge 'drm-tip/drm-tip' into devel-catchup-201806300333 git bisect good 78796877c37cb2c3898c4bcd2a12238d83858287 # 08:24 G 11 0 5 5 drm/i915: Move the irq_counter inside the spinlock git bisect good 57e23de02f4878061818fd118129a6b0e1516b11 # 08:43 G 10 0 5 7 drm/sun4i: DW HDMI: Expand algorithm for possible crtcs git bisect good 6e0ef9d85b99baeeea4b9c4a9777809cb0c6040a # 09:11 G 10 0 5 5 drm/amd/display: Write TEST_EDID_CHECKSUM_WRITE for EDID tests git bisect good 81d984fa3495f93aa4e9726598a8b4767eaca86f # 09:35 G 10 0 5 5 Merge remote-tracking branch 'drm/drm-next' into drm-tip git bisect good 186633be741825ed88fe3d92ef6f334364a26ee3 # 09:51 G 11 0 7 7 Merge remote-tracking branch 'drm-intel/drm-intel-next-queued' into drm-tip git bisect bad b1ee8b0d945633e4165f9e160af4cda8be6497f5 # 10:10 B 0 2 15 0 Documentation: e100: Fix docs build error git bisect good f25ae7126147dcbc5c2e80125d6ee941d0485e98 # 10:35 G 10 0 4 4 lockdep: finer-grained completion key for kthread git bisect bad 4b06b972bbb472ad77ba86397e8548e87318f8d5 # 10:53 B 0 1 14 0 mei: discard messages from not connected client during power down. git bisect bad 398ceb91b81505e7138eecdac870a59e85661671 # 11:19 B 0 2 15 0 RFC: debugobjects: capture stack traces at _init() time git bisect good ebaef7b2f7d0648b79f9475b5679bff4114fc1fa # 11:44 G 11 0 7 7 kernel/panic: Repeat the line and caller information at the end of the OOPS # first bad commit: [398ceb91b81505e7138eecdac870a59e85661671] RFC: debugobjects: capture stack traces at _init() time git bisect good ebaef7b2f7d0648b79f9475b5679bff4114fc1fa # 11:53 G 32 0 13 20 kernel/panic: Repeat the line and caller information at the end of the OOPS # extra tests with debug options git bisect bad 398ceb91b81505e7138eecdac870a59e85661671 # 12:09 B 0 8 21 0 RFC: debugobjects: capture stack traces at _init() time # extra tests on HEAD of linux-devel/devel-catchup-201806300333 git bisect bad 691ef198391e10a174dedbea19727b45d453ad47 # 12:09 B 0 13 29 0 0day head guard for 'devel-catchup-201806300333' # extra tests on tree/branch drm-intel/topic/core-for-CI git bisect bad b1ee8b0d945633e4165f9e160af4cda8be6497f5 # 12:16 B 0 13 26 0 Documentation: e100: Fix docs build error # extra tests with first bad commit reverted git bisect good b847b36176eff1c29f964bf7048fd7f8bf2f521a # 12:32 G 11 0 4 4 Revert "RFC: debugobjects: capture stack traces at _init() time" --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/lkp Intel Corporation