bisecting cause commit starting from 38e7571c07be01f9f19b355a9306a4e3d5cb0f5b building syzkaller on 12365b99ce83b8a58433eaedbe412dff563ef8fb testing commit 38e7571c07be01f9f19b355a9306a4e3d5cb0f5b with gcc (GCC) 8.1.0 all runs: crashed: KASAN: use-after-free Read in __vb2_perform_fileio testing release v5.0 testing commit 1c163f4c7b3f621efff9b28a47abb36f7378d783 with gcc (GCC) 8.1.0 all runs: crashed: KASAN: use-after-free Read in __vb2_perform_fileio testing release v4.20 testing commit 8fe28cb58bcb235034b64cbbb7550a8a43fd88be with gcc (GCC) 8.1.0 run #0: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #1: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #2: crashed: KASAN: null-ptr-deref Write in kthread_stop run #3: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #4: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #5: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #6: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #7: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #8: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #9: crashed: KASAN: use-after-free Read in __vb2_perform_fileio testing release v4.19 testing commit 84df9525b0c27f3ebc2ebb1864fa62a97fdedb7d with gcc (GCC) 8.1.0 run #0: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #1: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #2: crashed: KASAN: null-ptr-deref Write in kthread_stop run #3: crashed: KASAN: null-ptr-deref Write in kthread_stop run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap testing release v4.18 testing commit 94710cac0ef4ee177a63b5227664b38c95bbf703 with gcc (GCC) 8.1.0 run #0: crashed: KASAN: null-ptr-deref Write in kthread_stop run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in corrupted run #2: crashed: KASAN: null-ptr-deref Write in kthread_stop run #3: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap testing release v4.17 testing commit 29dcea88779c856c7dc92040a0c01233263101d4 with gcc (GCC) 8.1.0 run #0: crashed: KASAN: null-ptr-deref Write in kthread_stop run #1: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #2: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #3: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap testing release v4.16 testing commit 0adb32858b0bddf4ada5f364a84ed60b196dbcda with gcc (GCC) 8.1.0 run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in kthread_stop run #1: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #2: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #3: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap testing release v4.15 testing commit d8a5b80568a9cb66810e75b182018e9edb68e8ff with gcc (GCC) 8.1.0 run #0: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in kthread_stop run #2: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #3: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap testing release v4.14 testing commit bebc6082da0a9f5d47a1ea2edc099bf671058bd4 with gcc (GCC) 8.1.0 run #0: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #1: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in kthread_stop run #3: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap testing release v4.13 testing commit 569dbb88e80deb68974ef6fdd6a13edb9d686261 with gcc (GCC) 8.1.0 run #0: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #1: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #2: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #3: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap testing release v4.12 testing commit 6f7da290413ba713f0cdd9ff1a2a9bb129ef4f6c with gcc (GCC) 8.1.0 run #0: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #1: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #2: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #3: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap testing release v4.11 testing commit a351e9b9fc24e982ec2f0e76379a49826036da12 with gcc (GCC) 7.3.0 all runs: OK # git bisect start v4.12 v4.11 Bisecting: 7831 revisions left to test after this (roughly 13 steps) [2bd80401743568ced7d303b008ae5298ce77e695] Merge tag 'gpio-v4.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio testing commit 2bd80401743568ced7d303b008ae5298ce77e695 with gcc (GCC) 7.3.0 all runs: OK # git bisect good 2bd80401743568ced7d303b008ae5298ce77e695 Bisecting: 3830 revisions left to test after this (roughly 12 steps) [85d604902eb28eaea4f9e0f3a655ae986fa4bd2e] Merge tag 'armsoc-dt' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc testing commit 85d604902eb28eaea4f9e0f3a655ae986fa4bd2e with gcc (GCC) 7.3.0 run #0: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #1: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #2: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #3: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap # git bisect bad 85d604902eb28eaea4f9e0f3a655ae986fa4bd2e Bisecting: 1487 revisions left to test after this (roughly 11 steps) [c6a677c6f37bb7abc85ba7e3465e82b9f7eb1d91] Merge tag 'staging-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging testing commit c6a677c6f37bb7abc85ba7e3465e82b9f7eb1d91 with gcc (GCC) 7.3.0 init/initramfs.c:644:2: error: label at end of compound statement # git bisect skip c6a677c6f37bb7abc85ba7e3465e82b9f7eb1d91 Bisecting: 1487 revisions left to test after this (roughly 11 steps) [ea9a26d117cf0637c71d3e0076f4a124bf5859df] cxl: Force context lock during EEH flow testing commit ea9a26d117cf0637c71d3e0076f4a124bf5859df with gcc (GCC) 5.5.0 all runs: OK # git bisect good ea9a26d117cf0637c71d3e0076f4a124bf5859df Bisecting: 1487 revisions left to test after this (roughly 11 steps) [0352d1d852017953a5bdc5d735e3b9ff24fe63bd] staging: fsl-dpaa2/eth: Add APIs for DPNI objects testing commit 0352d1d852017953a5bdc5d735e3b9ff24fe63bd with gcc (GCC) 5.5.0 all runs: OK # git bisect good 0352d1d852017953a5bdc5d735e3b9ff24fe63bd Bisecting: 1316 revisions left to test after this (roughly 10 steps) [d484467c860dab3e17893d23b2238e1f581460fa] Merge tag 'xfs-4.12-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux testing commit d484467c860dab3e17893d23b2238e1f581460fa with gcc (GCC) 7.3.0 all runs: crashed: INFO: task hung in vivid_stop_generating_vid_cap # git bisect bad d484467c860dab3e17893d23b2238e1f581460fa Bisecting: 652 revisions left to test after this (roughly 9 steps) [7246f60068840847bdcf595be5f0b5ca632736e0] Merge tag 'powerpc-4.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux testing commit 7246f60068840847bdcf595be5f0b5ca632736e0 with gcc (GCC) 7.3.0 all runs: OK # git bisect good 7246f60068840847bdcf595be5f0b5ca632736e0 Bisecting: 345 revisions left to test after this (roughly 8 steps) [3622d3e77ecef090b5111e3c5423313f11711dfa] [media] ov2640: print error if devm_*_optional*() fails testing commit 3622d3e77ecef090b5111e3c5423313f11711dfa with gcc (GCC) 5.5.0 all runs: crashed: INFO: task hung in vivid_stop_generating_vid_cap # git bisect bad 3622d3e77ecef090b5111e3c5423313f11711dfa Bisecting: 153 revisions left to test after this (roughly 7 steps) [d5823511c0f8719a39e72ede1bce65411ac653b7] [media] dib0700: fix NULL-deref at probe testing commit d5823511c0f8719a39e72ede1bce65411ac653b7 with gcc (GCC) 5.5.0 all runs: OK # git bisect good d5823511c0f8719a39e72ede1bce65411ac653b7 Bisecting: 76 revisions left to test after this (roughly 6 steps) [08c4627c798b8c3c693438a2f61547920f39d333] [media] ov772x: avoid calling ov772x_select_params() twice testing commit 08c4627c798b8c3c693438a2f61547920f39d333 with gcc (GCC) 5.5.0 all runs: OK # git bisect good 08c4627c798b8c3c693438a2f61547920f39d333 Bisecting: 38 revisions left to test after this (roughly 5 steps) [30b2db3174bc58ddbedd034579d7aae61f3ad6ef] [media] docs-rst: Make the CSI-2 bus initialisation documentation match reality testing commit 30b2db3174bc58ddbedd034579d7aae61f3ad6ef with gcc (GCC) 5.5.0 run #0: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #1: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #2: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #3: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap # git bisect bad 30b2db3174bc58ddbedd034579d7aae61f3ad6ef Bisecting: 18 revisions left to test after this (roughly 4 steps) [09c716af36e6741032ebbe5e0502f65abc245b17] [media] media: i2c/ov5645: add the device tree binding document testing commit 09c716af36e6741032ebbe5e0502f65abc245b17 with gcc (GCC) 5.5.0 all runs: OK # git bisect good 09c716af36e6741032ebbe5e0502f65abc245b17 Bisecting: 8 revisions left to test after this (roughly 3 steps) [0244fd78231db16a9b0e44ac76da6a6208dc5ad4] [media] cx88: constify mb86a16_config structure testing commit 0244fd78231db16a9b0e44ac76da6a6208dc5ad4 with gcc (GCC) 5.5.0 all runs: crashed: INFO: task hung in vivid_stop_generating_vid_cap # git bisect bad 0244fd78231db16a9b0e44ac76da6a6208dc5ad4 Bisecting: 4 revisions left to test after this (roughly 2 steps) [56b27d4dd3eccff618be2f8417aef86f59a2c0d4] [media] drivers/media: Convert remaining use of pr_warning to pr_warn testing commit 56b27d4dd3eccff618be2f8417aef86f59a2c0d4 with gcc (GCC) 5.5.0 run #0: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #1: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #2: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #3: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap # git bisect bad 56b27d4dd3eccff618be2f8417aef86f59a2c0d4 Bisecting: 2 revisions left to test after this (roughly 1 step) [3bebcc4d6a9f8ed8020c7d1123199691b2dd989b] [media] Documentation: DT: Add OV5647 bindings testing commit 3bebcc4d6a9f8ed8020c7d1123199691b2dd989b with gcc (GCC) 5.5.0 all runs: OK # git bisect good 3bebcc4d6a9f8ed8020c7d1123199691b2dd989b Bisecting: 1 revision left to test after this (roughly 1 step) [3c2472a3c54895ecd6717a6454cd87994afdadea] [media] media: i2c: Add support for OV5647 sensor testing commit 3c2472a3c54895ecd6717a6454cd87994afdadea with gcc (GCC) 5.5.0 all runs: OK # git bisect good 3c2472a3c54895ecd6717a6454cd87994afdadea Bisecting: 0 revisions left to test after this (roughly 0 steps) [f2fe89061d79706eca5c47e4efdc09bbc171e74a] [media] vimc: Virtual Media Controller core, capture and sensor testing commit f2fe89061d79706eca5c47e4efdc09bbc171e74a with gcc (GCC) 5.5.0 run #0: crashed: KASAN: use-after-free Read in __vb2_perform_fileio run #1: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #2: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #3: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #4: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #5: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #6: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #7: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #8: crashed: INFO: task hung in vivid_stop_generating_vid_cap run #9: crashed: INFO: task hung in vivid_stop_generating_vid_cap # git bisect bad f2fe89061d79706eca5c47e4efdc09bbc171e74a f2fe89061d79706eca5c47e4efdc09bbc171e74a is the first bad commit commit f2fe89061d79706eca5c47e4efdc09bbc171e74a Author: Helen Koike Date: Fri Apr 7 14:55:19 2017 -0300 [media] vimc: Virtual Media Controller core, capture and sensor First version of the Virtual Media Controller. Add a simple version of the core of the driver, the capture and sensor nodes in the topology, generating a grey image in a hardcoded format. Signed-off-by: Helen Koike Signed-off-by: Hans Verkuil [hans.verkuil@cisco.com: fix small typo in Kconfig] Signed-off-by: Mauro Carvalho Chehab :100644 100644 0a16e1c5dc092d1f64afd6a604f83d8f1b517855 7d3b9993e4ba1b0b32b964ee6884a5d6cdd8d1f8 M MAINTAINERS :040000 040000 687c81eb72c7e351ade1e3eb80bdc8ee53ddb4e1 00e99c37ec439a81ca0c139365fec8392b59a390 M drivers revisions tested: 29, total time: 6h34m0.34059042s (build: 2h16m19.372286676s, test: 4h9m11.417077606s) first bad commit: f2fe89061d79706eca5c47e4efdc09bbc171e74a [media] vimc: Virtual Media Controller core, capture and sensor cc: ["hans.verkuil@cisco.com" "helen.koike@collabora.com" "linux-kernel@vger.kernel.org" "linux-media@vger.kernel.org" "mchehab@kernel.org" "mchehab@s-opensource.com"] crash: INFO: task hung in vivid_stop_generating_vid_cap IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready 8021q: adding VLAN 0 to HW filter on device batadv0 8021q: adding VLAN 0 to HW filter on device batadv0 INFO: task syz-executor.3:6875 blocked for more than 140 seconds. Not tainted 4.11.0-rc5+ #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28808 6875 6595 0x00000004 Call Trace: context_switch kernel/sched/core.c:2878 [inline] __schedule+0x935/0x1eb0 kernel/sched/core.c:3439 schedule+0x92/0x1b0 kernel/sched/core.c:3499 schedule_timeout+0x580/0xc30 kernel/time/timer.c:1688 do_wait_for_common kernel/sched/completion.c:77 [inline] __wait_for_common kernel/sched/completion.c:96 [inline] wait_for_common kernel/sched/completion.c:104 [inline] wait_for_completion+0x26b/0x3f0 kernel/sched/completion.c:125 kthread_stop+0xc2/0x610 kernel/kthread.c:521 vivid_stop_generating_vid_cap+0x195/0x6c0 drivers/media/platform/vivid/vivid-kthread-cap.c:931 vid_cap_stop_streaming+0x71/0xe0 drivers/media/platform/vivid/vivid-vid-cap.c:273 __vb2_queue_cancel+0x99/0x6e0 drivers/media/v4l2-core/videobuf2-core.c:1645 vb2_core_streamoff+0x62/0x140 drivers/media/v4l2-core/videobuf2-core.c:1769 __vb2_cleanup_fileio+0x69/0x150 drivers/media/v4l2-core/videobuf2-core.c:2283 vb2_core_queue_release+0xf/0x70 drivers/media/v4l2-core/videobuf2-core.c:2010 vb2_queue_release drivers/media/v4l2-core/videobuf2-v4l2.c:670 [inline] _vb2_fop_release+0x1af/0x260 drivers/media/v4l2-core/videobuf2-v4l2.c:841 vb2_fop_release+0x6a/0xd0 drivers/media/v4l2-core/videobuf2-v4l2.c:855 vivid_fop_release+0x163/0x400 drivers/media/platform/vivid/vivid-core.c:486 v4l2_release+0xeb/0x210 drivers/media/v4l2-core/v4l2-dev.c:446 __fput+0x25c/0x730 fs/file_table.c:209 ____fput+0x9/0x10 fs/file_table.c:245 task_work_run+0xd9/0x150 kernel/task_work.c:116 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x185/0x1c0 arch/x86/entry/common.c:161 prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline] syscall_return_slowpath+0x24f/0x2d0 arch/x86/entry/common.c:260 entry_SYSCALL_64_fastpath+0xc4/0xc6 RIP: 0033:0x411e31 RSP: 002b:00007ffce5202990 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000411e31 RDX: 0000000000000000 RSI: 0000000000740110 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000740108 R09: 000000000001118b R10: 00007ffce52028b0 R11: 0000000000000293 R12: 0000000000000001 R13: 00007ffce52029d0 R14: 0000000000000000 R15: 00007ffce52029e0 Showing all locks held in the system: 2 locks held by khungtaskd/980: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:172 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x109/0x9e0 kernel/hung_task.c:243 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4342 1 lock held by rsyslogd/6393: #0: (&f->f_pos_lock){+.+.+.}, at: [] __fdget_pos+0x84/0xb0 fs/file.c:781 2 locks held by getty/6483: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x1d1/0x1660 drivers/tty/n_tty.c:2133 2 locks held by getty/6484: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x1d1/0x1660 drivers/tty/n_tty.c:2133 2 locks held by getty/6485: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x1d1/0x1660 drivers/tty/n_tty.c:2133 2 locks held by getty/6486: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x1d1/0x1660 drivers/tty/n_tty.c:2133 2 locks held by getty/6487: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x1d1/0x1660 drivers/tty/n_tty.c:2133 2 locks held by getty/6488: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x1d1/0x1660 drivers/tty/n_tty.c:2133 2 locks held by getty/6489: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x1d1/0x1660 drivers/tty/n_tty.c:2133 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 980 Comm: khungtaskd Not tainted 4.11.0-rc5+ #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0xe6/0x120 lib/dump_stack.c:52 nmi_cpu_backtrace+0x137/0x160 lib/nmi_backtrace.c:100 nmi_trigger_cpumask_backtrace+0xf8/0x1a0 lib/nmi_backtrace.c:61 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 trigger_all_cpu_backtrace include/linux/nmi.h:95 [inline] check_hung_task kernel/hung_task.c:129 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:186 [inline] watchdog+0x62d/0x9e0 kernel/hung_task.c:243 kthread+0x2c9/0x3d0 kernel/kthread.c:229 ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff85eb2376