------------[ cut here ]------------
!iov_iter_count(&con->v2.in_iter)
WARNING: net/ceph/messenger_v2.c:3129 at populate_in_iter net/ceph/messenger_v2.c:3129 [inline], CPU#0: kworker/0:2/804
WARNING: net/ceph/messenger_v2.c:3129 at ceph_con_v2_try_read+0x6634/0x6810 net/ceph/messenger_v2.c:3159, CPU#0: kworker/0:2/804
Modules linked in:
CPU: 0 UID: 0 PID: 804 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: ceph-msgr ceph_con_workfn
RIP: 0010:populate_in_iter net/ceph/messenger_v2.c:3129 [inline]
RIP: 0010:ceph_con_v2_try_read+0x6634/0x6810 net/ceph/messenger_v2.c:3159
Code: 8d 3d 80 51 d3 04 43 0f b6 04 3e 84 c0 48 8b 54 24 38 0f 85 85 00 00 00 8b 32 67 48 0f b9 3a e9 40 ff ff ff e8 9d d7 2f f6 90 <0f> 0b 90 41 bd c3 ff ff ff e9 32 ff ff ff e8 89 d7 2f f6 90 0f 0b
RSP: 0018:ffffc90003c8f4a0 EFLAGS: 00010293
RAX: ffffffff8b973cb3 RBX: 0000000000000000 RCX: ffff88801d358000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003c8fa78 R08: 0000000000000005 R09: 0000000000000003
R10: ffff88801280069b R11: ffffed10025000d5 R12: fffff52000791ee4
R13: 0000000000000000 R14: 0000000000000010 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff88808c543000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffa640c37f0 CR3: 000000004feb6000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 ceph_con_workfn+0x1f5/0x14a0 net/ceph/messenger.c:1575
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>