Hello, syzbot found the following issue on: HEAD commit: e6251ab4551f Merge tag 'nfs-for-5.17-2' of git://git.linux.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=163caa3c700000 kernel config: https://syzkaller.appspot.com/x/.config?x=266de9da75c71a45 dashboard link: https://syzkaller.appspot.com/bug?extid=0abd373e2e50d704db87 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=108514a4700000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16ca671c700000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+0abd373e2e50d704db87@xxxxxxxxxxxxxxxxxxxxxxxxx INFO: task syz-executor117:3632 blocked for more than 143 seconds. Not tainted 5.17.0-rc3-syzkaller-00029-ge6251ab4551f #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor117 state:D stack:27512 pid: 3632 ppid: 3631 flags:0x00004002 Call Trace: <TASK> context_switch kernel/sched/core.c:4986 [inline] __schedule+0xab2/0x4db0 kernel/sched/core.c:6295 schedule+0xd2/0x260 kernel/sched/core.c:6368 schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857 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+0x174/0x270 kernel/sched/completion.c:138 vhost_work_dev_flush.part.0+0xbb/0xf0 drivers/vhost/vhost.c:243 vhost_work_dev_flush drivers/vhost/vhost.c:238 [inline] vhost_poll_flush+0x5e/0x80 drivers/vhost/vhost.c:252 vhost_vsock_flush drivers/vhost/vsock.c:710 [inline] vhost_vsock_dev_release+0x1be/0x4b0 drivers/vhost/vsock.c:757 __fput+0x286/0x9f0 fs/file_table.c:311 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 exit_task_work include/linux/task_work.h:32 [inline] do_exit+0xb29/0x2a30 kernel/exit.c:806 do_group_exit+0xd2/0x2f0 kernel/exit.c:935 __do_sys_exit_group kernel/exit.c:946 [inline] __se_sys_exit_group kernel/exit.c:944 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:944 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fbf04b83b89 RSP: 002b:00007fff5bc9ca18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fbf04bf8330 RCX: 00007fbf04b83b89 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 00007fff5bc9cc08 R10: 00007fff5bc9cc08 R11: 0000000000000246 R12: 00007fbf04bf8330 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001 </TASK> Showing all locks held in the system: 1 lock held by khungtaskd/26: #0: ffffffff8bb83c20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6460 2 locks held by getty/3275: #0: ffff88807f0db098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244 #1: ffffc90002b662e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2077 1 lock held by vhost-3632/3633: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 26 Comm: khungtaskd Not tainted 5.17.0-rc3-syzkaller-00029-ge6251ab4551f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline] watchdog+0xc1d/0xf50 kernel/hung_task.c:369 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK> Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3633 Comm: vhost-3632 Not tainted 5.17.0-rc3-syzkaller-00029-ge6251ab4551f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_kcov_mode kernel/kcov.c:166 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x60 kernel/kcov.c:200 Code: 00 00 e9 c6 41 66 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 65 8b 05 29 f7 89 7e 89 c1 48 8b 34 24 <81> e1 00 01 00 00 65 48 8b 14 25 00 70 02 00 a9 00 01 ff 00 74 0e RSP: 0018:ffffc90000cd7c78 EFLAGS: 00000246 RAX: 0000000080000000 RBX: ffff888079ca8a80 RCX: 0000000080000000 RDX: 0000000000000000 RSI: ffffffff86d3f8fb RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffc90000cd7c77 R10: ffffffff86d3f8ed R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffdf716a3b8 CR3: 00000000235b6000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> iotlb_access_ok+0x21b/0x3e0 drivers/vhost/vhost.c:1340 vq_meta_prefetch+0xbc/0x280 drivers/vhost/vhost.c:1366 vhost_transport_do_send_pkt+0xe0/0xfd0 drivers/vhost/vsock.c:104 vhost_worker+0x23d/0x3d0 drivers/vhost/vhost.c:372 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK> ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: e9 c6 41 66 02 jmpq 0x26641cd 7: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) d: 48 8b be b0 01 00 00 mov 0x1b0(%rsi),%rdi 14: e8 b4 ff ff ff callq 0xffffffcd 19: 31 c0 xor %eax,%eax 1b: c3 retq 1c: 90 nop 1d: 65 8b 05 29 f7 89 7e mov %gs:0x7e89f729(%rip),%eax # 0x7e89f74d 24: 89 c1 mov %eax,%ecx 26: 48 8b 34 24 mov (%rsp),%rsi * 2a: 81 e1 00 01 00 00 and $0x100,%ecx <-- trapping instruction 30: 65 48 8b 14 25 00 70 mov %gs:0x27000,%rdx 37: 02 00 39: a9 00 01 ff 00 test $0xff0100,%eax 3e: 74 0e je 0x4e --- This report is generated by a bot. 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