Attachment 5983 Details for Bug 35178 – xen-netback: skip pending packets in unmapped ring

[patch] xen-netback: skip pending packets in unmapped ring

0001-xen-netback-skip-pending-packets-in-unmapped-ring.patch (text/plain), 7.08 KB, created by Philipp Hahn on 2014-07-02 09:42:22 CEST

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Creator: Philipp Hahn

Created: 2014-07-02 09:42:22 CEST

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patch

obsolete

>From 45fd183c8faa5b7213aa4663cf224b414aacfc4b Mon Sep 17 00:00:00 2001
>Message-Id: <45fd183c8faa5b7213aa4663cf224b414aacfc4b.1404286695.git.hahn@univention.de>
>From: Wei Liu <wei.liu2@citrix.com>
>Date: Wed, 2 Jul 2014 09:14:22 +0200
>Subject: [PATCH] xen-netback: skip pending packets in unmapped ring
>Organization: Univention GmbH, Bremen, Germany
>
>1. The VM is receiving packets through bonding + bridge + netback +
>netfront.
>
>2. For some unknown reason at least one packet remains in the rx queue
>and is not delivered to the domU immediately by netback.
>
>3. The VM finishes shutting down.
>
>4. The shared ring between dom0 and domU is freed.
>
>5. then xen-netback continues processing the pending requests and tries
>to put the packet into the now already released shared ring.
>
>> [38551.547728] XXXlan0: port 9(vif26.0) entered disabled state
>> [38551.549365] BUG: unable to handle kernel paging request at ffffc900108641d8
>> [38551.549461] IP: [<ffffffffa04147dc>] xen_netbk_rx_action+0x18b/0x6f0
>> [xen_netback]
>> [38551.549551] PGD 57e20067 PUD 57e21067 PMD 571a7067 PTE 0
>> [38551.549615] Oops: 0000 [#1] SMP
>> [38551.549665] Modules linked in: tun xt_physdev xen_blkback xen_netback ip6_tables
>> iptable_filter ip_tables ebtable_nat ebtables x_tables xen_gntdev nfsv3 nfsv4
>> rpcsec_gss_krb5 nfsd nfs_acl auth_rpcgss oid_registry nfs fscache dns_resolver lockd
>> sunrpc fuse loop xen_blkfront xen_evtchn blktap quota_v2 quota_tree xenfs xen_privcmd
>> coretemp crc32c_intel ghash_clmulni_intel aesni_intel ablk_helper cryptd lrw gf128mul
>> glue_helper aes_x86_64 snd_pcm snd_timer snd soundcore snd_page_alloc tpm_tis tpm lpc_ich
>> tpm_bios i7core_edac i2c_i801 psmouse microcode edac_core serio_raw pcspkr mperf ioatdma
>> mfd_core processor evdev thermal_sys ext4 jbd2 crc16 bonding bridge stp llc dm_snapshot
>> dm_mirror dm_region_hash dm_log dm_mod sd_mod crc_t10dif ehci_pci uhci_hcd ehci_hcd mptsas
>> mptscsih mptbase scsi_transport_sas usbcore usb_common igb dca i2c_algo_bit i2c_core ptp
>> pps_core button
>> [38551.550601] CPU: 0 PID: 12587 Comm: netback/0 Not tainted 3.10.0-ucs58-amd64 #1 Debian
>> 3.10.11-1.58.201405060908
>> [38551.550693] Hardware name: FUJITSU PRIMERGY BX620 S6/D3051, BIOS 080015 Rev.3C78.3051
>> 07/22/2011
>> [38551.550781] task: ffff880004b067c0 ti: ffff8800561ec000 task.ti: ffff8800561ec000
>> [38551.550865] RIP: e030:[<ffffffffa04147dc>]  [<ffffffffa04147dc>]
>> xen_netbk_rx_action+0x18b/0x6f0 [xen_netback]
>> [38551.550959] RSP: e02b:ffff8800561edce8  EFLAGS: 00010202
>> [38551.551009] RAX: ffffc900104adac0 RBX: ffff8800541e95c0 RCX: ffffc90010864000
>> [38551.551064] RDX: 000000000000003b RSI: 0000000000000000 RDI: ffff880040014380
>> [38551.551120] RBP: ffff8800570e6800 R08: 0000000000000000 R09: ffff880004799800
>> [38551.551175] R10: ffffffff813ca115 R11: ffff88005e4fdb08 R12: ffff880054e6f800
>> [38551.551231] R13: ffff8800561edd58 R14: ffffc900104a1000 R15: 0000000000000000
>> [38551.551289] FS:  00007f19a54a8700(0000) GS:ffff88005da00000(0000)
>> knlGS:0000000000000000
>> [38551.551374] CS:  e033 DS: 0000 ES: 0000 CR0: 000000008005003b
>> [38551.551425] CR2: ffffc900108641d8 CR3: 0000000054cb3000 CR4: 0000000000002660
>> [38551.551481] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> [38551.551537] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
>> [38551.551592] Stack:
>> [38551.551630]  ffff880004b06ba0 0000000000000000 ffff88005da13ec0 ffff88005da13ec0
>> [38551.551726]  0000000004b067c0 ffffc900104a8ac0 ffffc900104a1020 000000005da13ec0
>> [38551.551823]  0000000000000000 0000000000000001 ffffc900104a8ac0 ffffc900104adac0
>> [38551.551920] Call Trace:
>> [38551.551966]  [<ffffffff813ca32d>] ? _raw_spin_lock_irqsave+0x11/0x2f
>> [38551.552021]  [<ffffffffa0416033>] ? xen_netbk_kthread+0x174/0x841 [xen_netback]
>> [38551.552106]  [<ffffffff8105d373>] ? wake_up_bit+0x20/0x20
>> [38551.560239]  [<ffffffffa0415ebf>] ? xen_netbk_tx_build_gops+0xce8/0xce8 [xen_netback]
>> [38551.560325]  [<ffffffff8105cd73>] ? kthread_freezable_should_stop+0x56/0x56
>> [38551.560381]  [<ffffffffa0415ebf>] ? xen_netbk_tx_build_gops+0xce8/0xce8 [xen_netback]
>> [38551.560466]  [<ffffffff8105ce1e>] ? kthread+0xab/0xb3
>> [38551.560518]  [<ffffffff81003638>] ? xen_end_context_switch+0xe/0x1c
>> [38551.560572]  [<ffffffff8105cd73>] ? kthread_freezable_should_stop+0x56/0x56
>> [38551.560628]  [<ffffffff813cfbfc>] ? ret_from_fork+0x7c/0xb0
>> [38551.560680]  [<ffffffff8105cd73>] ? kthread_freezable_should_stop+0x56/0x56
>> [38551.560734] Code: 8b b3 d0 00 00 00 48 8b bb d8 00 00 00 0f b7 74 37 02 89 70 08 eb 07
>> c7 40 08 00 00 00 00 89 d2 c7 40 04 00 00 00 00 48 83 c2 08 <0f> b7 34 d1 89 30 c7 44 24
>> 60 00 00 00 00 8b 44 d1 04 89 44 24
>> [38551.561151] RIP  [<ffffffffa04147dc>] xen_netbk_rx_action+0x18b/0x6f0 [xen_netback]
>> [38551.561238]  RSP <ffff8800561edce8>
>> [38551.561283] CR2: ffffc900108641d8
>> [38551.561624] ---[ end trace 8c260c6af259c4aa ]---
>
>Track the shared ring buffer being unmapped and drop those packets.
>
>Signed-off-by: Wei Liu <wei.liu2@citrix.com>
>Signed-off-by: Philipp Hahn <hahn@univention.de>
>Tested-by: Philipp Hahn <hahn@univention.de>
>---
> drivers/net/xen-netback/common.h    |  1 +
> drivers/net/xen-netback/interface.c |  1 +
> drivers/net/xen-netback/netback.c   | 10 ++++++++++
> 3 files changed, 12 insertions(+)
>
>diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
>index f2faa77..9239824 100644
>--- a/drivers/net/xen-netback/common.h
>+++ b/drivers/net/xen-netback/common.h
>@@ -66,6 +66,7 @@ struct xenvif {
> 	/* The shared rings and indexes. */
> 	struct xen_netif_tx_back_ring tx;
> 	struct xen_netif_rx_back_ring rx;
>+	bool mapped;
> 
> 	/* Frontend feature information. */
> 	u8 can_sg:1;
>diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
>index 540a796..5f11763 100644
>--- a/drivers/net/xen-netback/interface.c
>+++ b/drivers/net/xen-netback/interface.c
>@@ -271,6 +271,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
> 	vif->dev = dev;
> 	INIT_LIST_HEAD(&vif->schedule_list);
> 	INIT_LIST_HEAD(&vif->notify_list);
>+	vif->mapped = false;
> 
> 	vif->credit_bytes = vif->remaining_credit = ~0UL;
> 	vif->credit_usec  = 0UL;
>diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
>index 70b830f..bab7043 100644
>--- a/drivers/net/xen-netback/netback.c
>+++ b/drivers/net/xen-netback/netback.c
>@@ -720,6 +720,13 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk)
> 		vif = netdev_priv(skb->dev);
> 		nr_frags = skb_shinfo(skb)->nr_frags;
> 
>+		if (!vif->mapped) {
>+			netdev_err(vif->dev, "Shared ring is unmapped\n");
>+			dev_kfree_skb(skb);
>+			xenvif_put(vif);
>+			continue;
>+		}
>+
> 		sco = (struct skb_cb_overlay *)skb->cb;
> 		sco->meta_slots_used = netbk_gop_skb(skb, &npo);
> 
>@@ -1864,6 +1871,8 @@ static int xen_netbk_kthread(void *data)
> 
> void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
> {
>+	vif->mapped = false;
>+
> 	if (vif->tx.sring)
> 		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
> 					vif->tx.sring);
>@@ -1899,6 +1908,7 @@ int xen_netbk_map_frontend_rings(struct xenvif *vif,
> 	BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
> 
> 	vif->rx_req_cons_peek = 0;
>+	vif->mapped = true;
> 
> 	return 0;
> 
>-- 
>1.9.1
>

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Attachments on bug 35178: 5981 | 5983