Date:   Tue, 17 Jan 2017 22:48:32 +0100
From:   Nikola Ciprich <nikola.ciprich@...uxbox.cz>
To:     netdev@...r.kernel.org
Cc:     edumazet@...gle.com, nik@...uxbox.cz
Subject: 52bd2d62ce6758d811edcbd2256eb9ea7f6a56cb fixing crashes? -> 4.4
 stable?

Dear netdev developers,

I'd like to ask for a consultation regarding 4.4 kernel crashes.
we're using intel X540-AT2 10g controllers (onboard ones, on supermicro
boards) and we've noticed, then when using openvswitch, system very quickly
crashes on 4.4.x kernels we're usign. 4.5 is fine though.

here's backtrace gathered from system pstore:

<1>[ 1084.114586] BUG: unable to handle kernel paging request at ffff8840c365b5c4
<1>[ 1084.114918] IP: [<ffffffff81589802>] __netdev_pick_tx+0x92/0x140
<4>[ 1084.115101] PGD 2018067 PUD 0
<4>[ 1084.115270] Oops: 0000 [#1] SMP
<4>[ 1084.115439] Modules linked in: bonding(E) openvswitch(E) nf_defrag_ipv6(E) nf_conntrack(E) crc32_pclmul(E) aesni_intel(E) lrw(E) gf128mul(E) glue_helper(E) ablk_helper(E) cryptd(E) kvm
_intel(E) kvm(E) irqbypass(E) coretemp(E) crct10dif_pclmul(E) intel_powerclamp(E) x86_pkg_temp_thermal(E) ses(E) enclosure(E) iTCO_wdt(E) iTCO_vendor_support(E) mxm_wmi(E) i2c_i801(E) lpc_ic
h(E) mei_me(E) mfd_core(E) i2c_core(E) sb_edac(E) sg(E) mei(E) pcspkr(E) edac_core(E) ipmi_devintf(E) ioatdma(E) shpchp(E) wmi(E) ipmi_si(E) ipmi_msghandler(E) 8250_fintek(E) acpi_power_mete
r(E) acpi_pad(E) nfsd(E) auth_rpcgss(E) nfs_acl(E) lockd(E) grace(E) sunrpc(E) ip_tables(E) ext4(E) jbd2(E) mbcache(E) raid1(E) sd_mod(E) ahci(E) libahci(E) bnx2x(E) libcrc32c(E) ixgbe(E) cr
c32c_intel(E) libata(E) mdio(E) ptp(E) dca(E) megaraid_sas(E) pps_core(E) dm_mirror(E) dm_region_hash(E) dm_log(E) dm_mod(E)
<4>[ 1084.117683] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G            E   4.4.33lb7.01 #1
<4>[ 1084.118012] Hardware name: Supermicro X10DRi/X10DRI-T, BIOS 2.1 09/13/2016
<4>[ 1084.118181] task: ffffffff819f14c0 ti: ffffffff819e0000 task.ti: ffffffff819e0000
<4>[ 1084.118501] RIP: 0010:[<ffffffff81589802>]  [<ffffffff81589802>] __netdev_pick_tx+0x92/0x140
<4>[ 1084.118828] RSP: 0018:ffff883f7f003638  EFLAGS: 00010a02
<4>[ 1084.118994] RAX: 00000000aef55a76 RBX: 0000000000000000 RCX: 000000009d6e7dcd
<4>[ 1084.119164] RDX: 00000000ba9f4f5f RSI: ffff883f63f14d00 RDI: ffff883f7f0035ec
<4>[ 1084.119333] RBP: ffff883f7f003668 R08: 0000000000000003 R09: 00000000c8cfdbe1
<4>[ 1084.119506] R10: ffff883f61206042 R11: ffff883f7f0035c0 R12: 00000000ffffffff
<4>[ 1084.119679] R13: ffff883f657b00c0 R14: ffff883f5d920000 R15: 00000000f0000012
<4>[ 1084.119850] FS:  0000000000000000(0000) GS:ffff883f7f000000(0000) knlGS:0000000000000000
<4>[ 1084.120171] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[ 1084.120338] CR2: ffff8840c365b5c4 CR3: 00000000019ea000 CR4: 00000000003406f0
<4>[ 1084.120509] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
<4>[ 1084.120678] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
<4>[ 1084.120847] Stack:
<4>[ 1084.121006]  ffff883f63f14d00 ffff883f63f14d00 000000000000000e 0000000000000000
<4>[ 1084.121339]  ffff883f5d920000 ffff883f60a7f840 ffff883f7f0036a0 ffffffffa00fbed4
<4>[ 1084.121672]  ffff883f603612ac ffff883f5d920000 ffff883f63f14d00 0000000000000000
<4>[ 1084.122006] Call Trace:
<4>[ 1084.122168]  <IRQ>
<4>[ 1084.122193]  [<ffffffffa00fbed4>] ixgbe_select_queue+0xc4/0x150 [ixgbe]
<4>[ 1084.122519]  [<ffffffff8159111e>] netdev_pick_tx+0x5e/0xf0
<4>[ 1084.122687]  [<ffffffff81591252>] __dev_queue_xmit+0xa2/0x560
<4>[ 1084.122856]  [<ffffffff81591720>] dev_queue_xmit+0x10/0x20
<4>[ 1084.123034]  [<ffffffffa05e93a2>] bond_dev_queue_xmit+0x32/0x80 [bonding]
<4>[ 1084.123207]  [<ffffffffa05eb0d6>] bond_start_xmit+0x1a6/0x3f0 [bonding]
<4>[ 1084.123382]  [<ffffffff8124faa5>] ? ep_poll_callback+0xb5/0x160
<4>[ 1084.123551]  [<ffffffff81590f08>] dev_hard_start_xmit+0x238/0x3f0
<4>[ 1084.123721]  [<ffffffff815908cf>] ? netif_skb_features+0xff/0x200
<4>[ 1084.123890]  [<ffffffff815915f2>] __dev_queue_xmit+0x442/0x560
<4>[ 1084.124059]  [<ffffffff81591720>] dev_queue_xmit+0x10/0x20
<4>[ 1084.124232]  [<ffffffffa04fe70a>] ovs_vport_send+0x4a/0xc0 [openvswitch]
<4>[ 1084.124404]  [<ffffffffa04f1263>] do_output.isra.30+0x43/0x160 [openvswitch]
<4>[ 1084.124575]  [<ffffffff81579c5e>] ? __skb_clone+0x2e/0x140
<4>[ 1084.124744]  [<ffffffffa04f25c4>] do_execute_actions+0x684/0x7e0 [openvswitch]
<4>[ 1084.125067]  [<ffffffffa04f2752>] ovs_execute_actions+0x32/0xd0 [openvswitch]
<4>[ 1084.125240]  [<ffffffffa04f5ed4>] ovs_dp_process_packet+0x84/0x110 [openvswitch]
<4>[ 1084.125565]  [<ffffffffa04fdfec>] ovs_vport_receive+0x6c/0xd0 [openvswitch]
<4>[ 1084.125740]  [<ffffffff810b1645>] ? check_preempt_curr+0x75/0x90
<4>[ 1084.125912]  [<ffffffff810b1679>] ? ttwu_do_wakeup+0x19/0xe0
<4>[ 1084.126081]  [<ffffffff810b195d>] ? ttwu_do_activate.constprop.95+0x5d/0x70
<4>[ 1084.126252]  [<ffffffff810b23c7>] ? try_to_wake_up+0x47/0x340
<4>[ 1084.126427]  [<ffffffff810b2772>] ? default_wake_function+0x12/0x20
<4>[ 1084.126600]  [<ffffffff810ca51b>] ? autoremove_wake_function+0x2b/0x40
<4>[ 1084.126773]  [<ffffffffa04ff127>] netdev_frame_hook+0xe7/0x150 [openvswitch]
<4>[ 1084.126945]  [<ffffffff8158e840>] __netif_receive_skb_core+0x1e0/0x9e0
<4>[ 1084.127115]  [<ffffffff8167d4e6>] ? ipv6_gro_receive+0x246/0x360
<4>[ 1084.127284]  [<ffffffff8158f058>] __netif_receive_skb+0x18/0x60
<4>[ 1084.127453]  [<ffffffff8158f0e0>] netif_receive_skb_internal+0x40/0xb0
<4>[ 1084.127623]  [<ffffffff8158fd23>] napi_gro_receive+0xc3/0x110
<4>[ 1084.127813]  [<ffffffffa01e41fc>] bnx2x_rx_int+0x101c/0x19d0 [bnx2x]
<4>[ 1084.127984]  [<ffffffff810c37e3>] ? load_balance+0x163/0x8d0
<4>[ 1084.128166]  [<ffffffffa01e6a64>] bnx2x_poll+0x284/0x340 [bnx2x]
<4>[ 1084.128334]  [<ffffffff8158f4eb>] net_rx_action+0x16b/0x370
<4>[ 1084.128503]  [<ffffffff8108c032>] __do_softirq+0xe2/0x2e0
<4>[ 1084.128671]  [<ffffffff8108c4d5>] irq_exit+0xf5/0x100
<4>[ 1084.128843]  [<ffffffff816a0b06>] do_IRQ+0x56/0xd0
<4>[ 1084.129010]  [<ffffffff8169eb47>] common_interrupt+0x87/0x87
<4>[ 1084.129176]  <EOI>
<4>[ 1084.129188]  [<ffffffff8153e168>] ? cpuidle_enter_state+0xd8/0x250
<4>[ 1084.129510]  [<ffffffff8153e144>] ? cpuidle_enter_state+0xb4/0x250
<4>[ 1084.129681]  [<ffffffff8153e317>] cpuidle_enter+0x17/0x20
<4>[ 1084.129849]  [<ffffffff810ca832>] call_cpuidle+0x32/0x60
<4>[ 1084.130016]  [<ffffffff8153e2f3>] ? cpuidle_select+0x13/0x20
<4>[ 1084.130184]  [<ffffffff810caaf9>] cpu_startup_entry+0x299/0x360
<4>[ 1084.130354]  [<ffffffff8169201c>] rest_init+0x7c/0x80
<4>[ 1084.130521]  [<ffffffff81b5716a>] start_kernel+0x4cf/0x4f0
<4>[ 1084.134763]  [<ffffffff81b56a86>] ? set_init_arg+0x55/0x55
<4>[ 1084.134931]  [<ffffffff81b56120>] ? early_idt_handler_array+0x120/0x120
<4>[ 1084.135101]  [<ffffffff81b565ee>] x86_64_start_reservations+0x2a/0x2c
<4>[ 1084.135269]  [<ffffffff81b5673c>] x86_64_start_kernel+0x14c/0x16f
<4>[ 1084.135437] Code: 8b 7d 00 41 83 ff 01 0f 84 8b 00 00 00 f6 86 91 00 00 00 30 0f 84 85 00 00 00 8b 96 a4 00 00 00 44 89 f8 48 0f af c2 48 c1 e8 20 <41> 0f b7 44 45 18 41 3b 86 cc 03 00
 00 0f 83 81 00 00 00 44 39
<1>[ 1084.136184] RIP  [<ffffffff81589802>] __netdev_pick_tx+0x92/0x140
<4>[ 1084.136357]  RSP <ffff883f7f003638>
<4>[ 1084.136518] CR2: ffff8840c365b5c4
<4>[ 1084.137174] ---[ end trace 17b59260de82e18d ]---
<0>[ 1084.212189] Kernel panic - not syncing: Fatal exception in interrupt
<0>[ 1084.212482] Kernel Offset: disabled


I've bisected this to following commit:

commit 52bd2d62ce6758d811edcbd2256eb9ea7f6a56cb
Author: Eric Dumazet <edumazet@...gle.com>
Date:   Wed Nov 18 06:30:50 2015 -0800

    net: better skb->sender_cpu and skb->napi_id cohabitation
    
    skb->sender_cpu and skb->napi_id share a common storage,
    and we had various bugs about this.
    
    We had to call skb_sender_cpu_clear() in some places to
    not leave a prior skb->napi_id and fool netdev_pick_tx()
    
    As suggested by Alexei, we could split the space so that
    these errors can not happen.
    
    0 value being reserved as the common (not initialized) value,
    let's reserve [1 .. NR_CPUS] range for valid sender_cpu,
    and [NR_CPUS+1 .. ~0U] for valid napi_id.
    
    This will allow proper busy polling support over tunnels.


I'm by no means kernel developer and it doesn't make any sense
to me why this patch should be fixing it, but it is.. I've confirmed
it multiple times, that 4.4.32 without the patch crashes within
minutes, with it applied (it applies cleanly), it's rock solid.

therefore I'd probably like to propose this patch to -stable,
but I'd like to hear you, -netdev people opinion, especially
Erics..

what do you think about it?

thanks a lot in advance for reply

BR

nik







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