bisecting fixing commit since 13d2ce42de8cb98ff952f8de6307f896203854c2 building syzkaller on f213e07ead587b07a84e60c356520bce7277166c testing commit 13d2ce42de8cb98ff952f8de6307f896203854c2 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 92f1ad627c668308b0f3366fd09aa2f22ab024dd6c575f775f66b4badf700a7e run #0: basic kernel testing failed: BUG: program execution failed: executor NUM: failed to write control pipe: write |NUM: broken pipe run #1: crashed: INFO: task hung in n_tty_read run #2: crashed: INFO: task hung in n_tty_read run #3: crashed: INFO: task hung in n_tty_read run #4: crashed: INFO: task hung in n_tty_read run #5: crashed: INFO: task hung in n_tty_read run #6: crashed: INFO: task hung in n_tty_read run #7: crashed: INFO: task hung in n_tty_read run #8: crashed: INFO: task hung in n_tty_read run #9: crashed: INFO: task hung in n_tty_read run #10: crashed: INFO: task hung in n_tty_read run #11: crashed: INFO: task hung in n_tty_read run #12: crashed: INFO: task hung in n_tty_read run #13: crashed: INFO: task hung in n_tty_read run #14: crashed: INFO: task hung in n_tty_read run #15: crashed: INFO: task hung in n_tty_read run #16: crashed: INFO: task hung in console_callback run #17: crashed: INFO: task hung in console_callback run #18: crashed: INFO: task hung in n_tty_read run #19: crashed: INFO: task hung in console_callback testing current HEAD 59456c9cc40c8f75b5a7efa0fe1f211d9c6fcaf1 testing commit 59456c9cc40c8f75b5a7efa0fe1f211d9c6fcaf1 compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 73a16d7fdba6b48400e61acba0dafd27e0c31f8e61cd23e67ad122f86eb9d375 run #0: crashed: INFO: task hung in n_tty_read run #1: crashed: INFO: task hung in n_tty_read run #2: crashed: INFO: task hung in n_tty_read run #3: crashed: INFO: task hung in n_tty_read run #4: crashed: INFO: task hung in n_tty_read run #5: crashed: INFO: task hung in n_tty_read run #6: crashed: INFO: task hung in n_tty_read run #7: crashed: INFO: task hung in n_tty_read run #8: crashed: INFO: task hung in n_tty_read run #9: crashed: INFO: task hung in console_callback revisions tested: 2, total time: 35m39.101618163s (build: 21m42.182736327s, test: 13m16.146119102s) the crash still happens on HEAD commit msg: Linux 4.19.204 crash: INFO: task hung in console_callback Bluetooth: hci5: command 0x0406 tx timeout Bluetooth: hci0: command 0x0406 tx timeout Bluetooth: hci1: command 0x0406 tx timeout Bluetooth: hci2: command 0x0406 tx timeout Bluetooth: hci4: command 0x0406 tx timeout INFO: task kworker/0:3:8309 blocked for more than 140 seconds. Not tainted 4.19.204-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:3 D25464 8309 2 0x80000000 Workqueue: events console_callback Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6f6/0xd20 kernel/time/timer.c:1794 __down_common kernel/locking/semaphore.c:221 [inline] __down+0x180/0x2a0 kernel/locking/semaphore.c:238 down+0x5e/0x80 kernel/locking/semaphore.c:62 console_lock+0x23/0x70 kernel/printk/printk.c:2275 console_callback+0x71/0x370 drivers/tty/vt/vt.c:2832 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2153 worker_thread+0x85/0xb60 kernel/workqueue.c:2296 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 INFO: task syz-executor.5:13563 blocked for more than 140 seconds. Not tainted 4.19.204-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D29144 13563 8465 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6f6/0xd20 kernel/time/timer.c:1794 __down_common kernel/locking/semaphore.c:221 [inline] __down+0x180/0x2a0 kernel/locking/semaphore.c:238 down+0x5e/0x80 kernel/locking/semaphore.c:62 console_lock+0x23/0x70 kernel/printk/printk.c:2275 do_fb_ioctl+0x3fa/0x860 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xc8/0x140 drivers/video/fbdev/core/fbmem.c:1230 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465a49 Code: 50 10 31 db eb 0a 48 8b 72 08 48 89 d3 48 89 f2 48 85 d2 0f 84 d2 00 00 00 39 4a 30 75 e8 48 8b 4a 08 48 85 db 0f 84 9b 00 00 <00> 83 3d 3f c0 14 01 00 0f 85 7c 00 00 00 48 89 4b 08 48 89 54 24 RSP: 002b:00007fd997c77188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055bf40 RCX: 0000000000465a49 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bf40 R13: 00007ffe99982acf R14: 00007fd997c77300 R15: 0000000000022000 INFO: task syz-executor.1:13561 blocked for more than 140 seconds. Not tainted 4.19.204-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D29144 13561 8464 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6f6/0xd20 kernel/time/timer.c:1794 __down_common kernel/locking/semaphore.c:221 [inline] __down+0x180/0x2a0 kernel/locking/semaphore.c:238 down+0x5e/0x80 kernel/locking/semaphore.c:62 console_lock+0x23/0x70 kernel/printk/printk.c:2275 do_fb_ioctl+0x3fa/0x860 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xc8/0x140 drivers/video/fbdev/core/fbmem.c:1230 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465a49 Code: 50 10 31 db eb 0a 48 8b 72 08 48 89 d3 48 89 f2 48 85 d2 0f 84 d2 00 00 00 39 4a 30 75 e8 48 8b 4a 08 48 85 db 0f 84 9b 00 00 <00> 83 3d 3f c0 14 01 00 0f 85 7c 00 00 00 48 89 4b 08 48 89 54 24 RSP: 002b:00007f5680382188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055bf40 RCX: 0000000000465a49 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bf40 R13: 00007ffc187cea5f R14: 00007f5680382300 R15: 0000000000022000 INFO: task syz-executor.2:13562 blocked for more than 140 seconds. Not tainted 4.19.204-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D29144 13562 8455 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6f6/0xd20 kernel/time/timer.c:1794 __down_common kernel/locking/semaphore.c:221 [inline] __down+0x180/0x2a0 kernel/locking/semaphore.c:238 down+0x5e/0x80 kernel/locking/semaphore.c:62 console_lock+0x23/0x70 kernel/printk/printk.c:2275 do_fb_ioctl+0x3fa/0x860 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xc8/0x140 drivers/video/fbdev/core/fbmem.c:1230 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465a49 Code: 50 10 31 db eb 0a 48 8b 72 08 48 89 d3 48 89 f2 48 85 d2 0f 84 d2 00 00 00 39 4a 30 75 e8 48 8b 4a 08 48 85 db 0f 84 9b 00 00 <00> 83 3d 3f c0 14 01 00 0f 85 7c 00 00 00 48 89 4b 08 48 89 54 24 RSP: 002b:00007ff4da9a3188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055bf40 RCX: 0000000000465a49 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bf40 R13: 00007ffcce7143ef R14: 00007ff4da9a3300 R15: 0000000000022000 INFO: task syz-executor.0:13582 blocked for more than 140 seconds. Not tainted 4.19.204-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29176 13582 8462 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6f6/0xd20 kernel/time/timer.c:1794 __down_common kernel/locking/semaphore.c:221 [inline] __down+0x180/0x2a0 kernel/locking/semaphore.c:238 down+0x5e/0x80 kernel/locking/semaphore.c:62 console_lock+0x23/0x70 kernel/printk/printk.c:2275 do_fb_ioctl+0x3fa/0x860 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xc8/0x140 drivers/video/fbdev/core/fbmem.c:1230 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465a49 Code: 50 10 31 db eb 0a 48 8b 72 08 48 89 d3 48 89 f2 48 85 d2 0f 84 d2 00 00 00 39 4a 30 75 e8 48 8b 4a 08 48 85 db 0f 84 9b 00 00 <00> 83 3d 3f c0 14 01 00 0f 85 7c 00 00 00 48 89 4b 08 48 89 54 24 RSP: 002b:00007f55c3a9c188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055bf40 RCX: 0000000000465a49 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bf40 R13: 00007fffc57fcdcf R14: 00007f55c3a9c300 R15: 0000000000022000 INFO: task syz-executor.0:13591 blocked for more than 140 seconds. Not tainted 4.19.204-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29176 13591 8462 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6f6/0xd20 kernel/time/timer.c:1794 __down_common kernel/locking/semaphore.c:221 [inline] __down+0x180/0x2a0 kernel/locking/semaphore.c:238 down+0x5e/0x80 kernel/locking/semaphore.c:62 console_lock+0x23/0x70 kernel/printk/printk.c:2275 do_fb_ioctl+0x3fa/0x860 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xc8/0x140 drivers/video/fbdev/core/fbmem.c:1230 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465a49 Code: 50 10 31 db eb 0a 48 8b 72 08 48 89 d3 48 89 f2 48 85 d2 0f 84 d2 00 00 00 39 4a 30 75 e8 48 8b 4a 08 48 85 db 0f 84 9b 00 00 <00> 83 3d 3f c0 14 01 00 0f 85 7c 00 00 00 48 89 4b 08 48 89 54 24 RSP: 002b:00007f55c3a7b188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055bfe8 RCX: 0000000000465a49 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bfe8 R13: 00007fffc57fcdcf R14: 00007f55c3a7b300 R15: 0000000000022000 INFO: task syz-executor.3:13585 blocked for more than 140 seconds. Not tainted 4.19.204-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29176 13585 8458 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6f6/0xd20 kernel/time/timer.c:1794 __down_common kernel/locking/semaphore.c:221 [inline] __down+0x180/0x2a0 kernel/locking/semaphore.c:238 down+0x5e/0x80 kernel/locking/semaphore.c:62 console_lock+0x23/0x70 kernel/printk/printk.c:2275 do_fb_ioctl+0x3fa/0x860 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xc8/0x140 drivers/video/fbdev/core/fbmem.c:1230 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465a49 Code: 50 10 31 db eb 0a 48 8b 72 08 48 89 d3 48 89 f2 48 85 d2 0f 84 d2 00 00 00 39 4a 30 75 e8 48 8b 4a 08 48 85 db 0f 84 9b 00 00 <00> 83 3d 3f c0 14 01 00 0f 85 7c 00 00 00 48 89 4b 08 48 89 54 24 RSP: 002b:00007f8ef5786188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055bf40 RCX: 0000000000465a49 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bf40 R13: 00007ffff71988af R14: 00007f8ef5786300 R15: 0000000000022000 INFO: task syz-executor.3:13592 blocked for more than 140 seconds. Not tainted 4.19.204-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29176 13592 8458 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6f6/0xd20 kernel/time/timer.c:1794 __down_common kernel/locking/semaphore.c:221 [inline] __down+0x180/0x2a0 kernel/locking/semaphore.c:238 down+0x5e/0x80 kernel/locking/semaphore.c:62 console_lock+0x23/0x70 kernel/printk/printk.c:2275 do_fb_ioctl+0x3fa/0x860 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xc8/0x140 drivers/video/fbdev/core/fbmem.c:1230 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465a49 Code: 50 10 31 db eb 0a 48 8b 72 08 48 89 d3 48 89 f2 48 85 d2 0f 84 d2 00 00 00 39 4a 30 75 e8 48 8b 4a 08 48 85 db 0f 84 9b 00 00 <00> 83 3d 3f c0 14 01 00 0f 85 7c 00 00 00 48 89 4b 08 48 89 54 24 RSP: 002b:00007f8ef5765188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055bfe8 RCX: 0000000000465a49 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bfe8 R13: 00007ffff71988af R14: 00007f8ef5765300 R15: 0000000000022000 INFO: task syz-executor.4:13584 blocked for more than 140 seconds. Not tainted 4.19.204-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D29176 13584 8460 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6f6/0xd20 kernel/time/timer.c:1794 __down_common kernel/locking/semaphore.c:221 [inline] __down+0x180/0x2a0 kernel/locking/semaphore.c:238 down+0x5e/0x80 kernel/locking/semaphore.c:62 console_lock+0x23/0x70 kernel/printk/printk.c:2275 do_fb_ioctl+0x3fa/0x860 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xc8/0x140 drivers/video/fbdev/core/fbmem.c:1230 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465a49 Code: 50 10 31 db eb 0a 48 8b 72 08 48 89 d3 48 89 f2 48 85 d2 0f 84 d2 00 00 00 39 4a 30 75 e8 48 8b 4a 08 48 85 db 0f 84 9b 00 00 <00> 83 3d 3f c0 14 01 00 0f 85 7c 00 00 00 48 89 4b 08 48 89 54 24 RSP: 002b:00007fa17afac188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055bf40 RCX: 0000000000465a49 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bf40 R13: 00007ffeff78b90f R14: 00007fa17afac300 R15: 0000000000022000 INFO: task syz-executor.4:13590 blocked for more than 140 seconds. Not tainted 4.19.204-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D29176 13590 8460 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x6f6/0xd20 kernel/time/timer.c:1794 __down_common kernel/locking/semaphore.c:221 [inline] __down+0x180/0x2a0 kernel/locking/semaphore.c:238 down+0x5e/0x80 kernel/locking/semaphore.c:62 console_lock+0x23/0x70 kernel/printk/printk.c:2275 do_fb_ioctl+0x3fa/0x860 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xc8/0x140 drivers/video/fbdev/core/fbmem.c:1230 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x465a49 Code: 50 10 31 db eb 0a 48 8b 72 08 48 89 d3 48 89 f2 48 85 d2 0f 84 d2 00 00 00 39 4a 30 75 e8 48 8b 4a 08 48 85 db 0f 84 9b 00 00 <00> 83 3d 3f c0 14 01 00 0f 85 7c 00 00 00 48 89 4b 08 48 89 54 24 RSP: 002b:00007fa17af8b188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055bfe8 RCX: 0000000000465a49 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 00000000004af682 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bfe8 R13: 00007ffeff78b90f R14: 00007fa17af8b300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1563: #0: 000000009240a0af (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:4443 7 locks held by kworker/u4:4/2889: 1 lock held by in:imklog/7791: #0: 00000000cfc3d69f (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xa7/0xd0 fs/file.c:767 2 locks held by agetty/7806: #0: 0000000046b9373f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x2d/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000000537ef70 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x1ee/0x1910 drivers/tty/n_tty.c:2154 2 locks held by kworker/0:3/8309: #0: 00000000c7864b7a ((wq_completion)"events"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2124 #1: 0000000099af1bbb (console_work){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2128 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1563 Comm: khungtaskd Not tainted 4.19.204-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x17c/0x226 lib/dump_stack.c:118 nmi_cpu_backtrace.cold.0+0x3c/0x78 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xf6/0x120 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x5c3/0xb40 kernel/hung_task.c:287 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 2889 Comm: kworker/u4:4 Not tainted 4.19.204-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound flush_to_ldisc RIP: 0010:vga16fb_fillrect+0x881/0x19b0 drivers/video/fbdev/vga16fb.c:924 Code: 8d 70 ff 85 c0 0f 84 30 fd ff ff 4c 63 7d c8 41 8d 7c 24 ff 31 d2 48 83 c7 01 49 8d 04 3e 45 85 e4 0f 84 0b 07 00 00 41 88 16 <49> 83 c6 01 49 39 c6 75 f4 4e 8d 34 38 83 ee 01 83 fe ff 75 db e9 RSP: 0018:ffff8880abc4f418 EFLAGS: 00000283 RAX: ffff8880000a0050 RBX: 0000000000000000 RCX: 00000000ffffffb0 RDX: 0000000000000000 RSI: 000000004da79516 RDI: 0000000000000050 RBP: ffff8880abc4f490 R08: ffff8880abc4f4dc R09: 0000000000000000 R10: 1ffff110277c4eb9 R11: 0000000000000000 R12: 0000000000000050 R13: 1ffffffff132249a R14: ffff8880000a0011 R15: ffffffffffffffb0 FS: 0000000000000000(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000002b04848 CR3: 00000000b3b00000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bit_clear+0x314/0x630 drivers/video/fbdev/core/bitblit.c:74 fbcon_clear+0x475/0x700 drivers/video/fbdev/core/fbcon.c:1258 fbcon_scroll+0x618/0x3530 drivers/video/fbdev/core/fbcon.c:1759 con_scroll+0x467/0x700 drivers/tty/vt/vt.c:637 lf+0x23b/0x2a0 drivers/tty/vt/vt.c:1492 do_con_write.part.13+0x10f0/0x1aa0 drivers/tty/vt/vt.c:2769 do_con_write drivers/tty/vt/vt.c:3157 [inline] con_put_char+0xaf/0xc0 drivers/tty/vt/vt.c:3156 tty_put_char+0xac/0x130 drivers/tty/tty_io.c:2892 do_output_char+0x1c9/0x700 drivers/tty/n_tty.c:486 __process_echoes+0x287/0x790 drivers/tty/n_tty.c:737 commit_echoes+0x10e/0x160 drivers/tty/n_tty.c:792 n_tty_receive_char_fast drivers/tty/n_tty.c:1447 [inline] n_tty_receive_buf_fast drivers/tty/n_tty.c:1607 [inline] __receive_buf drivers/tty/n_tty.c:1642 [inline] n_tty_receive_buf_common+0x1363/0x2db0 drivers/tty/n_tty.c:1740 n_tty_receive_buf2+0xf/0x20 drivers/tty/n_tty.c:1775 tty_ldisc_receive_buf+0x86/0x1b0 drivers/tty/tty_buffer.c:456 tty_port_default_receive_buf+0x5f/0x90 drivers/tty/tty_port.c:38 receive_buf drivers/tty/tty_buffer.c:476 [inline] flush_to_ldisc+0x1aa/0x3a0 drivers/tty/tty_buffer.c:528 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2153 worker_thread+0x85/0xb60 kernel/workqueue.c:2296 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 ---------------- Code disassembly (best guess): 0: 8d 70 ff lea -0x1(%rax),%esi 3: 85 c0 test %eax,%eax 5: 0f 84 30 fd ff ff je 0xfffffd3b b: 4c 63 7d c8 movslq -0x38(%rbp),%r15 f: 41 8d 7c 24 ff lea -0x1(%r12),%edi 14: 31 d2 xor %edx,%edx 16: 48 83 c7 01 add $0x1,%rdi 1a: 49 8d 04 3e lea (%r14,%rdi,1),%rax 1e: 45 85 e4 test %r12d,%r12d 21: 0f 84 0b 07 00 00 je 0x732 27: 41 88 16 mov %dl,(%r14) * 2a: 49 83 c6 01 add $0x1,%r14 <-- trapping instruction 2e: 49 39 c6 cmp %rax,%r14 31: 75 f4 jne 0x27 33: 4e 8d 34 38 lea (%rax,%r15,1),%r14 37: 83 ee 01 sub $0x1,%esi 3a: 83 fe ff cmp $0xffffffff,%esi 3d: 75 db jne 0x1a 3f: e9 .byte 0xe9