On Tue, Nov 15, 2016 at 7:27 AM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > Hello, > > The following program produces a deadlocked, unkillable process: > https://gist.githubusercontent.com/dvyukov/fb7e93f6618f4eccb84d419ea6cec491/raw/a14b60250e593eb1b61f50cead41059dc49ceff2/gistfile1.txt > > > # cat /proc/9362/task/*/stack > [<ffffffff815b9be8>] __synchronize_srcu+0x2f8/0x4a0 kernel/rcu/srcu.c:448 > [<ffffffff815b9df3>] synchronize_srcu_expedited+0x13/0x20 kernel/rcu/srcu.c:510 > [<ffffffff8108891b>] kvm_io_bus_register_dev+0x2ab/0x3e0 > arch/x86/kvm/../../../virt/kvm/kvm_main.c:3559 > [<ffffffff8117f676>] kvm_create_pit+0x5c6/0x8c0 arch/x86/kvm/i8254.c:694 > [<ffffffff810df816>] kvm_arch_vm_ioctl+0x1406/0x23c0 arch/x86/kvm/x86.c:3956 > [<ffffffff81082b4a>] kvm_vm_ioctl+0x1fa/0x1a70 > arch/x86/kvm/../../../virt/kvm/kvm_main.c:3099 > [< inline >] vfs_ioctl fs/ioctl.c:43 > [<ffffffff81abcb44>] do_vfs_ioctl+0x1c4/0x1630 fs/ioctl.c:679 > [< inline >] SYSC_ioctl fs/ioctl.c:694 > [<ffffffff81abe044>] SyS_ioctl+0x94/0xc0 fs/ioctl.c:685 > [<ffffffff88143885>] entry_SYSCALL_64_fastpath+0x23/0xc6 > arch/x86/entry/entry_64.S:209 > [<ffffffffffffffff>] 0xffffffffffffffff > > [<ffffffff81199103>] kvm_hv_set_msr_common+0x163/0x2a30 > arch/x86/kvm/hyperv.c:1145 > [<ffffffff810bf82b>] kvm_set_msr_common+0xb0b/0x23a0 arch/x86/kvm/x86.c:2261 > [<ffffffff811cdcdd>] vmx_set_msr+0x27d/0xcb0 arch/x86/kvm/vmx.c:3149 > [<ffffffff81094879>] kvm_set_msr+0xd9/0x170 arch/x86/kvm/x86.c:1084 > [<ffffffff81094c23>] do_set_msr+0x123/0x1a0 arch/x86/kvm/x86.c:1113 > [< inline >] __msr_io arch/x86/kvm/x86.c:2523 > [<ffffffff810bd2b0>] msr_io+0x250/0x460 arch/x86/kvm/x86.c:2560 > [<ffffffff810d9f10>] kvm_arch_vcpu_ioctl+0x360/0x44a0 arch/x86/kvm/x86.c:3401 > [<ffffffff8107aef7>] kvm_vcpu_ioctl+0x237/0x11c0 > arch/x86/kvm/../../../virt/kvm/kvm_main.c:2710 > [< inline >] vfs_ioctl fs/ioctl.c:43 > [<ffffffff81abcb44>] do_vfs_ioctl+0x1c4/0x1630 fs/ioctl.c:679 > [< inline >] SYSC_ioctl fs/ioctl.c:694 > [<ffffffff81abe044>] SyS_ioctl+0x94/0xc0 fs/ioctl.c:685 > [<ffffffff88143885>] entry_SYSCALL_64_fastpath+0x23/0xc6 > arch/x86/entry/entry_64.S:209 > > [<ffffffffffffffff>] 0xffffffffffffffff > [<ffffffff810de0ff>] kvm_vm_ioctl_get_dirty_log+0x8f/0x210 > arch/x86/kvm/x86.c:3779 > [<ffffffff81083b34>] kvm_vm_ioctl+0x11e4/0x1a70 > arch/x86/kvm/../../../virt/kvm/kvm_main.c:2969 > [< inline >] vfs_ioctl fs/ioctl.c:43 > [<ffffffff81abcb44>] do_vfs_ioctl+0x1c4/0x1630 fs/ioctl.c:679 > [< inline >] SYSC_ioctl fs/ioctl.c:694 > [<ffffffff81abe044>] SyS_ioctl+0x94/0xc0 fs/ioctl.c:685 > [<ffffffff88143885>] entry_SYSCALL_64_fastpath+0x23/0xc6 > arch/x86/entry/entry_64.S:209 > [<ffffffffffffffff>] 0xffffffffffffffff > > > INFO: task syz-executor:5833 blocked for more than 120 seconds. > Not tainted 4.9.0-rc5+ #28 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > syz-executor D17872 5833 4082 0x00000004 > ffff880033944780 ffff8800602f5100 ffff8800652b0c80 ffff8800391a2380 > ffff88006d122cd8 ffff8800368763a8 ffffffff8812c15c 0000000041b58ab3 > ffff88006d123668 ffff88006d123640 1ffff10006d0ec5c ffff88006d122cd8 > Call Trace: > [<ffffffff8812d8bd>] schedule+0x10d/0x460 kernel/sched/core.c:3457 > [<ffffffff8812e7e5>] schedule_preempt_disabled+0x15/0x20 > kernel/sched/core.c:3490 > [< inline >] __mutex_lock_common kernel/locking/mutex.c:582 > [<ffffffff881339f6>] mutex_lock_nested+0x686/0xf20 kernel/locking/mutex.c:621 > [<ffffffff81199143>] kvm_hv_set_msr_common+0x163/0x2a30 > arch/x86/kvm/hyperv.c:1145 > [<ffffffff810bf7fb>] kvm_set_msr_common+0xb0b/0x23a0 arch/x86/kvm/x86.c:2261 > [<ffffffff811cdd1d>] vmx_set_msr+0x27d/0xcb0 arch/x86/kvm/vmx.c:3149 > [<ffffffff81094849>] kvm_set_msr+0xd9/0x170 arch/x86/kvm/x86.c:1084 > [<ffffffff81094bf3>] do_set_msr+0x123/0x1a0 arch/x86/kvm/x86.c:1113 > [< inline >] __msr_io arch/x86/kvm/x86.c:2523 > [<ffffffff810bd280>] msr_io+0x250/0x460 arch/x86/kvm/x86.c:2560 > [<ffffffff810d9ee0>] kvm_arch_vcpu_ioctl+0x360/0x44a0 arch/x86/kvm/x86.c:3401 > [<ffffffff8107aee7>] kvm_vcpu_ioctl+0x237/0x11c0 > arch/x86/kvm/../../../virt/kvm/kvm_main.c:2708 > [< inline >] vfs_ioctl fs/ioctl.c:43 > [<ffffffff81abcb44>] do_vfs_ioctl+0x1c4/0x1630 fs/ioctl.c:679 > [< inline >] SYSC_ioctl fs/ioctl.c:694 > [<ffffffff81abe044>] SyS_ioctl+0x94/0xc0 fs/ioctl.c:685 > [<ffffffff88143885>] entry_SYSCALL_64_fastpath+0x23/0xc6 > > [ 3319.345108] Showing all locks held in the system: > [ 3319.349897] 2 locks held by khungtaskd/1328: > [ 3319.352888] #0: [ 3319.354562] ( > rcu_read_lock[ 3319.358168] ){......} > , at: [ 3319.360511] [<ffffffff816f636c>] watchdog+0x1cc/0xd70 > [ 3319.363841] #1: [ 3319.364761] ( > tasklist_lock[ 3319.367215] ){.+.+..} > , at: [ 3319.369197] [<ffffffff81560332>] debug_show_all_locks+0xd2/0x420 > [ 3319.374809] 3 locks held by syz-executor/5833: > [ 3319.388745] #0: [ 3319.390145] ( > &vcpu->mutex[ 3319.391749] ){+.+.+.} > , at: [ 3319.392313] [<ffffffff8106cd41>] vcpu_load+0x21/0x70 > [ 3319.396281] #1: [ 3319.398802] ( > &kvm->srcu[ 3319.399431] ){......} > , at: [ 3319.399883] [<ffffffff810bd178>] msr_io+0x148/0x460 > [ 3319.403905] #2: [ 3319.404639] ( > &kvm->lock[ 3319.406582] ){+.+.+.} > , at: [ 3319.409670] [<ffffffff81199143>] kvm_hv_set_msr_common+0x163/0x2a30 > [ 3319.422421] 2 locks held by syz-executor/5849: > [ 3319.425646] #0: [ 3319.426948] ( > &kvm->lock[ 3319.427747] ){+.+.+.} > , at: [ 3319.428368] [<ffffffff810def2e>] kvm_arch_vm_ioctl+0xb4e/0x23c0 > [ 3319.429594] #1: [ 3319.429942] ( > &kvm->slots_lock[ 3319.430881] ){+.+.+.} > , at: [ 3319.431631] [<ffffffff8117f679>] kvm_create_pit+0x589/0x8c0 > > > On commit a25f0944ba9b1d8a6813fd6f1a86f1bd59ac25a6 (Nov 13) kvm_vm_ioctl_get_dirty_log is probably unrelated because I also see following deadlocks: # cat /proc/7169/task/*/stack [<ffffffff815b9be8>] __synchronize_srcu+0x2f8/0x4a0 [<ffffffff815b9df3>] synchronize_srcu_expedited+0x13/0x20 [<ffffffff8108891b>] kvm_io_bus_register_dev+0x2ab/0x3e0 [<ffffffff8117f676>] kvm_create_pit+0x5c6/0x8c0 [<ffffffff810df816>] kvm_arch_vm_ioctl+0x1406/0x23c0 [<ffffffff81082b4a>] kvm_vm_ioctl+0x1fa/0x1a70 [<ffffffff81abcb44>] do_vfs_ioctl+0x1c4/0x1630 [<ffffffff81abe044>] SyS_ioctl+0x94/0xc0 [<ffffffff88143885>] entry_SYSCALL_64_fastpath+0x23/0xc6 [<ffffffffffffffff>] 0xffffffffffffffff [<ffffffff81199103>] kvm_hv_set_msr_common+0x163/0x2a30 [<ffffffff810bf82b>] kvm_set_msr_common+0xb0b/0x23a0 [<ffffffff811cdcdd>] vmx_set_msr+0x27d/0xcb0 [<ffffffff81094879>] kvm_set_msr+0xd9/0x170 [<ffffffff81094c23>] do_set_msr+0x123/0x1a0 [<ffffffff810bd2b0>] msr_io+0x250/0x460 [<ffffffff810d9f10>] kvm_arch_vcpu_ioctl+0x360/0x44a0 [<ffffffff8107aef7>] kvm_vcpu_ioctl+0x237/0x11c0 [<ffffffff81abcb44>] do_vfs_ioctl+0x1c4/0x1630 [<ffffffff81abe044>] SyS_ioctl+0x94/0xc0 [<ffffffff88143885>] entry_SYSCALL_64_fastpath+0x23/0xc6 [<ffffffffffffffff>] 0xffffffffffffffff -- To unsubscribe from this list: send the line "unsubscribe 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