Hi!
I am getting a stack trace and broken/stalled transfers with Samba I
have "vfs objects = io_uring" in smb.conf.
Using Samba-4.13.9, the problem occurs in at least kernel-5.12.17-19 and
5.13.4. I haven't tried earlier kernels.
[52928.008736] ------------[ cut here ]------------
[52928.008740] WARNING: CPU: 3 PID: 2173 at fs/io_uring.c:8749
io_ring_exit_work+0xbd/0x5f0
[52928.008753] Modules linked in: nf_conntrack_netlink vhost_net vhost
vhost_iotlb tap tun xt_CHECKSUM xt_MASQUERADE xt_state ip6t_REJECT
nf_reject_ipv6 ip6table_filter ip6table_raw ip6table_mangle ip6table_nat
xt_multiport xt_limit ipt_REJECT nf_reject_ipv4 xt_NFLOG nfnetlink_log
xt_conntrack xt_physdev iptable_filter iptable_mangle xt_nat iptable_nat
xt_CT iptable_raw ip_set_bitmap_port ip_set_hash_ip ip_set_hash_net
xt_esp ipt_ah nft_xfrm nf_tables nf_nat_pptp nf_conntrack_pptp nf_nat
nf_conntrack_sip nf_conntrack_irc nf_conntrack_ftp nf_conntrack_h323
nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_bridge
nf_conntrack nf_defrag_ipv6 ip6_tables ip_tables xt_recent xt_set ip_set
nfnetlink nf_defrag_ipv4 nf_socket_ipv4 binfmt_misc amdgpu kvm_amd
drm_ttm_helper kvm ttm gpu_sched k10temp uas irqbypass 8250 8250_base
serial_mctrl_gpio video serial_core backlight pinctrl_amd
[52928.008821] CPU: 3 PID: 2173 Comm: kworker/u32:4 Not tainted
5.13.4-gentoo-e350 #1
[52928.008826] Hardware name: Gigabyte Technology Co., Ltd. B450M
DS3H/B450M DS3H-CF, BIOS F61c 05/10/2021
[52928.008829] Workqueue: events_unbound io_ring_exit_work
[52928.008835] RIP: 0010:io_ring_exit_work+0xbd/0x5f0
[52928.008841] Code: 00 00 00 4c 89 fa 48 c7 c6 b0 7e 30 83 e8 5b 7f 00
00 4c 89 f7 e8 43 95 ff ff 48 8b 05 9c 75 0f 01 49 39 c5 0f 89 7b ff ff
ff <0f> 0b e9 74 ff ff ff 48 c7 c2 c8 b0 af 84 48 c7 c6 be 99 1c 84 48
[52928.008845] RSP: 0018:ffffa52294007df0 EFLAGS: 00010293
[52928.008849] RAX: 0000000103237dd4 RBX: ffff89359ef92600 RCX:
0000000000000008
[52928.008852] RDX: ffff89359ef92080 RSI: 0000000000000000 RDI:
ffff89359ef924c0
[52928.008855] RBP: ffffa52294007e90 R08: 0000000000000001 R09:
0000000000000000
[52928.008857] R10: 0000000000000000 R11: 0000000000000003 R12:
ffff89359ef925d0
[52928.008858] R13: 0000000103237dc0 R14: 0000000000000000 R15:
ffff89359ef92000
[52928.008861] FS: 0000000000000000(0000) GS:ffff8937a6ec0000(0000)
knlGS:0000000000000000
[52928.008864] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[52928.008867] CR2: 00007f13f7904001 CR3: 00000001b62be000 CR4:
00000000003506e0
[52928.008871] Call Trace:
[52928.008876] ? __switch_to+0x23b/0x420
[52928.008882] process_one_work+0x1af/0x300
[52928.008889] worker_thread+0x48/0x3c0
[52928.008894] ? process_one_work+0x300/0x300
[52928.008899] kthread+0x122/0x140
[52928.008903] ? set_kthread_struct+0x30/0x30
[52928.008908] ret_from_fork+0x22/0x30
[52928.008914] ---[ end trace 6a275af934ed94fd ]---
I set "log level = 3" in smb.conf and captured the results:
Windows client: https://paste.tnonline.net/files/1U7Do7BKokPa_smbd-log.txt
Linux client: https://paste.tnonline.net/files/r4yebSzlGEVD_linux-client.txt
[2021/07/24 16:46:49.793735, 3]
../../source3/smbd/smb2_read.c:415(smb2_read_complete)
smbd_smb2_read: fnum 4007995332, file
media/vm/libvirt/images/NomadBSD.img, length=1048576 offset=1282408448
read=1048576
[2021/07/24 16:46:49.803693, 3]
../../source3/smbd/smb2_read.c:415(smb2_read_complete)
smbd_smb2_read: fnum 4007995332, file
media/vm/libvirt/images/NomadBSD.img, length=1048576 offset=1283457024
read=1048576
[2021/07/24 16:46:49.811478, 3]
../../source3/smbd/smb2_read.c:415(smb2_read_complete)
smbd_smb2_read: fnum 4007995332, file
media/vm/libvirt/images/NomadBSD.img, length=1048576 offset=1284505600
read=1048576
... here it just stops adding to the log file and the client eventually
times out waiting for more data. No apparent error message in any of the
samba log files.
The stack trace "events_unbound io_ring_exit_work" only seems to occur
once and then doesn't come back in subsequent testing, even if I restart
Samba itself. It comes back after a reboot.
This happens every time I have the io_uring vfs module enabled and never
otherwise. It seems to be only large (several GB) file transfers that
are affected.
