Hello, syzbot found the following issue on: HEAD commit: b36c9697 Add linux-next specific files for 20200828 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=156a598e900000 kernel config: https://syzkaller.appspot.com/x/.config?x=5e3cf99580b5542c dashboard link: https://syzkaller.appspot.com/bug?extid=c3df2ca09fe4beef4d67 compiler: gcc (GCC) 10.1.0-syz 20200507 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16c3301e900000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16d2df49900000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c3df2ca09fe4beef4d67@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task syz-executor787:6840 can't die for more than 143 seconds. task:syz-executor787 state:D stack:26864 pid: 6840 ppid: 6833 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1855 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion_timeout+0x15e/0x270 kernel/sched/completion.c:157 usb_start_wait_urb+0x144/0x2b0 drivers/usb/core/message.c:63 usb_bulk_msg+0x226/0x550 drivers/usb/core/message.c:254 do_proc_bulk+0x39b/0x710 drivers/usb/core/devio.c:1231 proc_bulk drivers/usb/core/devio.c:1268 [inline] usbdev_do_ioctl drivers/usb/core/devio.c:2542 [inline] usbdev_ioctl+0x586/0x3360 drivers/usb/core/devio.c:2708 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x449659 Code: Bad RIP value. RSP: 002b:00007f02ac79cdb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000006dac28 RCX: 0000000000449659 RDX: 0000000020000000 RSI: 00000000c0185502 RDI: 0000000000000003 RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac2c R13: 00007ffe8f1fe93f R14: 00007f02ac79d9c0 R15: 20c49ba5e353f7cf INFO: task syz-executor787:6840 blocked for more than 143 seconds. Not tainted 5.9.0-rc2-next-20200828-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor787 state:D stack:26864 pid: 6840 ppid: 6833 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1855 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion_timeout+0x15e/0x270 kernel/sched/completion.c:157 usb_start_wait_urb+0x144/0x2b0 drivers/usb/core/message.c:63 usb_bulk_msg+0x226/0x550 drivers/usb/core/message.c:254 do_proc_bulk+0x39b/0x710 drivers/usb/core/devio.c:1231 proc_bulk drivers/usb/core/devio.c:1268 [inline] usbdev_do_ioctl drivers/usb/core/devio.c:2542 [inline] usbdev_ioctl+0x586/0x3360 drivers/usb/core/devio.c:2708 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x449659 Code: Bad RIP value. RSP: 002b:00007f02ac79cdb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000006dac28 RCX: 0000000000449659 RDX: 0000000020000000 RSI: 00000000c0185502 RDI: 0000000000000003 RBP: 00000000006dac20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac2c R13: 00007ffe8f1fe93f R14: 00007f02ac79d9c0 R15: 20c49ba5e353f7cf Showing all locks held in the system: 1 lock held by khungtaskd/1173: #0: ffffffff89c67640 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5825 1 lock held by in:imklog/6531: #0: ffff888098a9c130 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1173 Comm: khungtaskd Not tainted 5.9.0-rc2-next-20200828-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline] watchdog+0xd89/0xf30 kernel/hung_task.c:339 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3891 Comm: systemd-journal Not tainted 5.9.0-rc2-next-20200828-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:3109 [inline] RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3128 [inline] RIP: 0010:validate_chain kernel/locking/lockdep.c:3183 [inline] RIP: 0010:__lock_acquire+0x1750/0x5640 kernel/locking/lockdep.c:4426 Code: 74 5d 49 bd 00 00 00 00 00 fc ff df 48 8b 54 24 08 eb 06 49 83 ec 08 74 46 49 8d 7c 24 18 48 89 f8 48 c1 e8 03 42 80 3c 28 00 <0f> 85 43 2a 00 00 49 8b 44 24 18 48 39 c2 0f 84 26 f5 ff ff 49 8d RSP: 0018:ffffc90004807b00 EFLAGS: 00000046 RAX: 1ffffffff1806a53 RBX: 0000000000003fe4 RCX: ffffffff815a153b RDX: 62386d250e98b09e RSI: 0000000000000008 RDI: ffffffff8c035298 RBP: ffff888093da49f0 R08: 0000000000000000 R09: ffffffff8c6a59f7 R10: fffffbfff18d4b3e R11: 0000000000000000 R12: ffffffff8c035280 R13: dffffc0000000000 R14: ffff888093da4100 R15: 0000000000000001 FS: 00007ff896ba08c0(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff893f44000 CR3: 000000009398b000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1f1/0xad0 kernel/locking/lockdep.c:5005 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] __alloc_fd+0x34/0x600 fs/file.c:500 do_sys_openat2+0x134/0x420 fs/open.c:1166 do_sys_open fs/open.c:1184 [inline] __do_sys_open fs/open.c:1192 [inline] __se_sys_open fs/open.c:1188 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1188 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7ff896130840 Code: 73 01 c3 48 8b 0d 68 77 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 89 bb 20 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 1e f6 ff ff 48 89 04 24 RSP: 002b:00007fffa7dee6b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007fffa7dee9c0 RCX: 00007ff896130840 RDX: 00000000000001a0 RSI: 0000000000080042 RDI: 0000560b7f41acd0 RBP: 000000000000000d R08: 000000000000ffc0 R09: 00000000ffffffff R10: 0000000000000069 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000560b7f40f040 R14: 00007fffa7dee980 R15: 0000560b7f41aaf0 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
