On 10/15/2019 1:25 AM, Tonghao Zhang wrote:
On Tue, Oct 15, 2019 at 6:26 AM Gregory Rose <gvrose8...@gmail.com> wrote:
[snip]
Hi Tonghao,
I did make the change you suggested:
git diff
diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index bc14b12..210018a 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -827,6 +827,8 @@ static int tbl_mask_array_add_mask(struct flow_table
*tbl,
MASK_ARRAY_SIZE_MIN);
if (err)
return err;
+
+ ma = ovsl_dereference(tbl->mask_array);
}
However, there is still an issue. Apparently this change just moves the
bug. Now I'm getting this splat:
[ 512.147478] ------------[ cut here ]------------
[ 512.147481] kernel BUG at net/openvswitch/flow_table.c:725!
[ 512.147526] invalid opcode: 0000 [#1] SMP PTI
[ 512.147552] CPU: 1 PID: 14636 Comm: ovs-vswitchd Tainted:
G E 5.4.0-rc1+ #138
[ 512.147595] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[ 512.147630] RIP: 0010:ovs_flow_tbl_remove+0x151/0x160 [openvswitch]
[ 512.147663] Code: 55 f7 ea 89 f0 c1 f8 1f 29 c2 39 53 10 0f 8f 6a ff
ff ff 48 89 ef d1 fe 5b 5d e9 8a ed ff ff 0f 0b 0f 0b b8 18 00 00 00 eb
92 <0f> 0b 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 57
[ 512.147753] RSP: 0018:ffffb637002cf8c8 EFLAGS: 00010246
[ 512.147781] RAX: 0000000000000009 RBX: ffff95ebf32d23c0 RCX:
ffff95ebf00e5a00
[ 512.147817] RDX: ffff95ebf32d2420 RSI: 0000000000000009 RDI:
ffff95ebf0dffba0
[ 512.147852] RBP: ffffb637002cfb70 R08: ffff95ebf6030240 R09:
ffff95ebf1643180
[ 512.147888] R10: ffff95ebf283b814 R11: ffffffffc0932500 R12:
ffff95ebf040a300
[ 512.147924] R13: ffff95ebf0dffba0 R14: ffff95ebf283b814 R15:
0000000000000007
[ 512.147961] FS: 00007fbbab3d2980(0000) GS:ffff95ebf7a80000(0000)
knlGS:0000000000000000
[ 512.148001] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 512.148031] CR2: 00007fffca190ff8 CR3: 0000000232810006 CR4:
00000000001606e0
[ 512.148071] Call Trace:
[ 512.148092] action_fifos_exit+0x3240/0x37b0 [openvswitch]
[ 512.148125] ? update_sd_lb_stats+0x613/0x760
[ 512.148152] ? find_busiest_group+0x3e/0x520
[ 512.148177] ? __nla_validate_parse+0x57/0x8a0
[ 512.148203] ? _cond_resched+0x15/0x40
[ 512.148226] ? genl_family_rcv_msg_attrs_parse+0xe4/0x110
[ 512.148256] genl_rcv_msg+0x1ed/0x430
[ 512.148303] ? __switch_to_asm+0x34/0x70
[ 512.148326] ? __switch_to_asm+0x40/0x70
[ 512.148349] ? __switch_to_asm+0x34/0x70
[ 512.148371] ? __switch_to_asm+0x40/0x70
[ 512.148394] ? __switch_to_asm+0x34/0x70
[ 512.148416] ? __switch_to_asm+0x40/0x70
[ 512.148439] ? genl_family_rcv_msg_attrs_parse+0x110/0x110
[ 512.148470] netlink_rcv_skb+0x4a/0x110
[ 512.148492] genl_rcv+0x24/0x40
[ 512.148512] netlink_unicast+0x1a0/0x250
[ 512.148536] netlink_sendmsg+0x2b4/0x3b0
[ 512.148560] sock_sendmsg+0x5b/0x60
[ 512.148582] ___sys_sendmsg+0x278/0x2f0
[ 512.148607] ? file_update_time+0x60/0x130
[ 512.148630] ? pipe_write+0x286/0x400
[ 512.148653] ? new_sync_write+0x12d/0x1d0
[ 512.148676] ? __sys_sendmsg+0x5e/0xa0
[ 512.148697] __sys_sendmsg+0x5e/0xa0
[ 512.148720] do_syscall_64+0x52/0x1a0
[ 512.148742] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 512.148771] RIP: 0033:0x7fbbaa6f9a6d
[ 512.149622] Code: b9 20 00 00 75 10 b8 2e 00 00 00 0f 05 48 3d 01 f0
ff ff 73 31 c3 48 83 ec 08 e8 fe f6 ff ff 48 89 04 24 b8 2e 00 00 00 0f
05 <48> 8b 3c 24 48 89 c2 e8 47 f7 ff ff 48 89 d0 48 83 c4 08 48 3d 01
[ 512.151428] RSP: 002b:00007fffca1a1100 EFLAGS: 00000293 ORIG_RAX:
000000000000002e
[ 512.152349] RAX: ffffffffffffffda RBX: 0000000000000001 RCX:
00007fbbaa6f9a6d
[ 512.153266] RDX: 0000000000000000 RSI: 00007fffca1a1160 RDI:
0000000000000010
[ 512.154184] RBP: 0000000000f42680 R08: 0000000000000000 R09:
00007fffca1a2118
[ 512.155094] R10: 0000000000000008 R11: 0000000000000293 R12:
00007fffca1a1f30
[ 512.155992] R13: 00007fffca1a20c0 R14: 00007fffca1a1f38 R15:
00007fffca1a15f0
[ 512.156866] Modules linked in: vport_vxlan(E) vxlan(E) vport_gre(E)
ip_gre(E) ip_tunnel(E) vport_geneve(E) geneve(E) ip6_udp_tunnel(E)
udp_tunnel(E) openvswitch(E) nsh(E) nf_conncount(E) nf_nat_tftp(E)
nf_conntrack_tftp(E) nf_nat_ftp(E) nf_conntrack_ftp(E) nf_nat(E)
nf_conntrack_netlink(E) ip6table_filter(E) ip6_tables(E)
iptable_filter(E) ip_tables(E) x_tables(E) ip6_gre(E) ip6_tunnel(E)
tunnel6(E) gre(E) bonding(E) 8021q(E) garp(E) stp(E) mrp(E) llc(E)
veth(E) nfnetlink_cttimeout(E) nfnetlink(E) nf_conntrack(E)
nf_defrag_ipv6(E) nf_defrag_ipv4(E) binfmt_misc(E) intel_rapl_msr(E)
snd_hda_codec_generic(E) ledtrig_audio(E) snd_hda_intel(E)
snd_intel_nhlt(E) snd_hda_codec(E) intel_rapl_common(E) snd_hda_core(E)
snd_hwdep(E) input_leds(E) snd_pcm(E) joydev(E) snd_timer(E)
serio_raw(E) snd(E) soundcore(E) i2c_piix4(E) mac_hid(E) ib_iser(E)
rdma_cm(E) iw_cm(E) ib_cm(E) ib_core(E) configfs(E) iscsi_tcp(E)
libiscsi_tcp(E) libiscsi(E) scsi_transport_iscsi(E) autofs4(E) btrfs(E)
zstd_decompress(E)
[ 512.156899] zstd_compress(E) raid10(E) raid456(E)
async_raid6_recov(E) async_memcpy(E) async_pq(E) async_xor(E)
async_tx(E) xor(E) raid6_pq(E) libcrc32c(E) raid1(E) raid0(E)
multipath(E) linear(E) crct10dif_pclmul(E) crc32_pclmul(E)
ghash_clmulni_intel(E) aesni_intel(E) crypto_simd(E) qxl(E) ttm(E)
cryptd(E) glue_helper(E) drm_kms_helper(E) syscopyarea(E) sysfillrect(E)
sysimgblt(E) fb_sys_fops(E) psmouse(E) drm(E) pata_acpi(E) floppy(E)
[last unloaded: nf_conntrack_ftp]
[ 512.168488] ---[ end trace 26730810beeb11e1 ]---
[ 512.169555] RIP: 0010:ovs_flow_tbl_remove+0x151/0x160 [openvswitch]
[ 512.170638] Code: 55 f7 ea 89 f0 c1 f8 1f 29 c2 39 53 10 0f 8f 6a ff
ff ff 48 89 ef d1 fe 5b 5d e9 8a ed ff ff 0f 0b 0f 0b b8 18 00 00 00 eb
92 <0f> 0b 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 57
[ 512.172813] RSP: 0018:ffffb637002cf8c8 EFLAGS: 00010246
[ 512.173897] RAX: 0000000000000009 RBX: ffff95ebf32d23c0 RCX:
ffff95ebf00e5a00
[ 512.174991] RDX: ffff95ebf32d2420 RSI: 0000000000000009 RDI:
ffff95ebf0dffba0
[ 512.176109] RBP: ffffb637002cfb70 R08: ffff95ebf6030240 R09:
ffff95ebf1643180
[ 512.177229] R10: ffff95ebf283b814 R11: ffffffffc0932500 R12:
ffff95ebf040a300
[ 512.178364] R13: ffff95ebf0dffba0 R14: ffff95ebf283b814 R15:
0000000000000007
[ 512.179530] FS: 00007fbbab3d2980(0000) GS:ffff95ebf7a80000(0000)
knlGS:0000000000000000
[ 512.180700] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 512.181885] CR2: 00007fffca190ff8 CR3: 0000000232810006 CR4:
00000000001606e0
The code is hitting this:
static void tbl_mask_array_del_mask(struct flow_table *tbl,
struct sw_flow_mask *mask)
{
struct mask_array *ma = ovsl_dereference(tbl->mask_array);
int i;
/* Remove the deleted mask pointers from the array */
for (i = 0; i < ma->count; i++) {
if (mask == ovsl_dereference(ma->masks[i]))
goto found;
}
BUG(); <---------------------------- Here
Pravin mentioned memory barrier usage in one of his replies. Perhaps
that is an avenue to explore.
Hi Pravin, Greg
I run the make check-kernel for a long time, and don't reproduce it.
Greg, how did you reproduce it?
Hi Tonghao,
I use a Ubuntu 16.04 base system with updates all applied and build the
net-next kernel (with your
patches applied) and then install it.
I boot to the new kernel and then build the current master branch of OVS
from github:
./boot.sh
mkdir _build
cd _build
../configure
make -j8
I then run 'sudo make check-kernel TESTSUITEFLAGS="63"'
Hope this helps with your repro.
Thanks,
- Greg
For using barrier, i should add READ_ONCE in flow_lookup in fast path
(read-side ), and use WRITE_ONCE in
tbl_mask_array_add/del_mask (write-side) protected by ovs_mutex. Other
read-side (protected by ovs_mutex),
e.g
* flow_mask_find
* ovs_flow_tbl_lookup_exact
* ovs_flow_tbl_num_masks
can access ma->count directly ?
Thanks,
- Greg
