------------[ 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#3: kworker/3:3/5814
WARNING: net/ceph/messenger_v2.c:3129 at ceph_con_v2_try_read+0x1727/0x4780 net/ceph/messenger_v2.c:3159, CPU#3: kworker/3:3/5814
Modules linked in:
CPU: 3 UID: 0 PID: 5814 Comm: kworker/3:3 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+0x1727/0x4780 net/ceph/messenger_v2.c:3159
Code: 08 0f 85 4d 2d 00 00 48 81 c4 38 02 00 00 89 d8 5b 5d 41 5c 41 5d 41 5e 41 5f e9 c4 c7 3c 00 4c 8b 64 24 28 e8 9a d6 88 f6 90 <0f> 0b 90 bb c3 ff ff ff e8 8c d6 88 f6 49 8d 7f 30 48 b8 00 00 00
RSP: 0018:ffffc900039df978 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8b818191
RDX: ffff88802d7b0000 RSI: ffffffff8b8189a6 RDI: ffff88802d7b0000
RBP: 0000000000000010 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff9200073bf3e
R13: ffffc900039dfab0 R14: ffff888059388698 R15: ffff888059388418
FS:  0000000000000000(0000) GS:ffff8880d60dc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb231e9aff8 CR3: 000000003d35e000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 ceph_con_workfn+0x360/0x13e0 net/ceph/messenger.c:1575
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>