Hello, syzbot found the following issue on: HEAD commit: 4442749a Add linux-next specific files for 20200902 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=138e7285900000 kernel config: https://syzkaller.appspot.com/x/.config?x=39134fcec6c78e33 dashboard link: https://syzkaller.appspot.com/bug?extid=3227d097b95b4207b570 compiler: gcc (GCC) 10.1.0-syz 20200507 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15306279900000 The issue was bisected to: commit dfe127799f8e663c7e3e48b5275ca538b278177b Author: Stefano Garzarella <sgarzare@xxxxxxxxxx> Date: Thu Aug 27 14:58:31 2020 +0000 io_uring: allow disabling rings during the creation bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15b09115900000 final oops: https://syzkaller.appspot.com/x/report.txt?x=17b09115900000 console output: https://syzkaller.appspot.com/x/log.txt?x=13b09115900000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+3227d097b95b4207b570@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: dfe127799f8e ("io_uring: allow disabling rings during the creation") INFO: task syz-executor.0:28543 can't die for more than 143 seconds. task:syz-executor.0 state:D stack:28824 pid:28543 ppid: 6864 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:3777 [inline] __schedule+0xea9/0x2230 kernel/sched/core.c:4526 schedule+0xd0/0x2a0 kernel/sched/core.c:4601 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+0x163/0x260 kernel/sched/completion.c:138 io_sq_thread_stop fs/io_uring.c:6906 [inline] io_finish_async fs/io_uring.c:6920 [inline] io_sq_offload_create fs/io_uring.c:7595 [inline] io_uring_create fs/io_uring.c:8671 [inline] io_uring_setup+0x1495/0x29a0 fs/io_uring.c:8744 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5b9 Code: Bad RIP value. RSP: 002b:00007fde24a51bf8 EFLAGS: 00000206 ORIG_RAX: 00000000000001a9 RAX: ffffffffffffffda RBX: 0000000020000240 RCX: 000000000045d5b9 RDX: 00000000206d5000 RSI: 0000000020000240 RDI: 0000000000007e71 RBP: 000000000118cf98 R08: 0000000020000100 R09: 0000000020000100 R10: 0000000000000000 R11: 0000000000000206 R12: 00000000206d5000 R13: 00000000206d4000 R14: 0000000020000100 R15: 0000000000000000 INFO: task syz-executor.0:28543 blocked for more than 143 seconds. Not tainted 5.9.0-rc3-next-20200902-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:28824 pid:28543 ppid: 6864 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:3777 [inline] __schedule+0xea9/0x2230 kernel/sched/core.c:4526 schedule+0xd0/0x2a0 kernel/sched/core.c:4601 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+0x163/0x260 kernel/sched/completion.c:138 io_sq_thread_stop fs/io_uring.c:6906 [inline] io_finish_async fs/io_uring.c:6920 [inline] io_sq_offload_create fs/io_uring.c:7595 [inline] io_uring_create fs/io_uring.c:8671 [inline] io_uring_setup+0x1495/0x29a0 fs/io_uring.c:8744 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5b9 Code: Bad RIP value. RSP: 002b:00007fde24a51bf8 EFLAGS: 00000206 ORIG_RAX: 00000000000001a9 RAX: ffffffffffffffda RBX: 0000000020000240 RCX: 000000000045d5b9 RDX: 00000000206d5000 RSI: 0000000020000240 RDI: 0000000000007e71 RBP: 000000000118cf98 R08: 0000000020000100 R09: 0000000020000100 R10: 0000000000000000 R11: 0000000000000206 R12: 00000000206d5000 R13: 00000000206d4000 R14: 0000000020000100 R15: 0000000000000000 INFO: task io_uring-sq:28548 blocked for more than 143 seconds. Not tainted 5.9.0-rc3-next-20200902-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:io_uring-sq state:D stack:31120 pid:28548 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3777 [inline] __schedule+0xea9/0x2230 kernel/sched/core.c:4526 schedule+0xd0/0x2a0 kernel/sched/core.c:4601 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4660 kthread+0x2ac/0x4a0 kernel/kthread.c:285 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Showing all locks held in the system: 1 lock held by khungtaskd/1174: #0: ffffffff89c67980 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5829 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1174 Comm: khungtaskd Not tainted 5.9.0-rc3-next-20200902-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+0x198/0x1fd 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3906 Comm: systemd-journal Not tainted 5.9.0-rc3-next-20200902-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:25 [inline] RIP: 0010:static_key_false include/linux/jump_label.h:200 [inline] RIP: 0010:trace_irq_disable_rcuidle include/trace/events/preemptirq.h:36 [inline] RIP: 0010:trace_hardirqs_off kernel/trace/trace_preemptirq.c:82 [inline] RIP: 0010:trace_hardirqs_off+0x6c/0x210 kernel/trace/trace_preemptirq.c:74 Code: 81 e3 00 00 f0 00 31 ff 89 de e8 9f 37 fa ff 85 db 74 0d 5b 5d 41 5c 41 5d 41 5e e9 0e 3b fa ff e8 09 3b fa ff 4c 8b 6c 24 28 <0f> 1f 44 00 00 e8 fa 3a fa ff eb dd e8 f3 3a fa ff 65 8b 1d bc fe RSP: 0018:ffffc90005357f00 EFLAGS: 00000093 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff817a9471 RDX: ffff888092cbe500 RSI: ffffffff817a9487 RDI: 0000000000000005 RBP: ffffc90005357f58 R08: 0000000000000001 R09: ffff888092cbee08 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff87f9c83e R14: 0000000000000000 R15: 0000000000000000 FS: 00007f7fd426b8c0(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7fd161d000 CR3: 00000000933ac000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: local_irq_disable_exit_to_user include/linux/entry-common.h:166 [inline] syscall_exit_to_user_mode+0xae/0x2e0 kernel/entry/common.c:241 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f7fd3504f17 Code: ff ff ff 48 8b 4d a0 0f b7 51 fe 48 8b 4d a8 66 89 54 08 fe e9 1a ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 b8 27 00 00 00 0f 05 <c3> 0f 1f 84 00 00 00 00 00 b8 6e 00 00 00 0f 05 c3 0f 1f 84 00 00 RSP: 002b:00007ffc0a1045c8 EFLAGS: 00000206 ORIG_RAX: 0000000000000027 RAX: 0000000000000f42 RBX: 000055ca0d4b51e0 RCX: 00007f7fd3504f17 RDX: 00007ffc0a104688 RSI: 0000000000000001 RDI: 000055ca0d4b51e0 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000206 R12: 00007ffc0a104688 R13: 0000000000000f42 R14: 00007ffc0a107470 R15: 00007ffc0a104a80 --- 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. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
