From: Olaf Hering <olaf@aepfle.de>
To: xen-devel@lists.xenproject.org, Wei Liu <wei.liu2@citrix.com>,
Paul Durrant <paul.durrant@citrix.com>
Subject: bogus wrap check in xen-netback
Date: Wed, 25 Apr 2018 09:19:56 +0200 [thread overview]
Message-ID: <20180425091956.7e4c98bc.olaf@aepfle.de> (raw)
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With commit 48856286b64e ("xen/netback: shutdown the ring if it contains garbage.") a new check was added to xen-netback, which triggers for me.
Since there are bugs in ring buffer handling I tried to trigger them earlier by changing RING_IDX from u32 to u16. Now I found another one, and I wonder if the error below could potentially also hit with u32:
...
[ 624.186492] br0: port 3(vif2.0) entered forwarding state
[ 624.186522] br0: port 3(vif2.0) entered forwarding state
[ 680.865398] vif vif-1-0 vif1.0: Impossible number of requests. req_prod 0, req_cons 65400, size 256
[ 680.865402] vif vif-1-0 vif1.0: fatal error; disabling device
[ 680.865495] br0: port 2(vif1.0) entered disabled state
[ 689.433849] vif vif-2-0 vif2.0: Impossible number of requests. req_prod 0, req_cons 65527, size 256
[ 689.433857] vif vif-2-0 vif2.0: fatal error; disabling device
[ 689.433945] br0: port 3(vif2.0) entered disabled state
[ 690.930512] pktgen: Packet Generator for packet performance testing. Version: 2.75
...
What exactly is that check in xenvif_tx_build_gops trying to achieve? Subtracting a non-zero value from zero will always create something larger than XEN_NETIF_TX_RING_SIZE.
Olaf
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next reply other threads:[~2018-04-25 7:20 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-25 7:19 Olaf Hering [this message]
2018-04-25 7:28 ` bogus wrap check in xen-netback Juergen Gross
2018-04-25 7:39 ` Olaf Hering
2018-04-25 8:59 ` Wei Liu
2018-04-25 9:04 ` Olaf Hering
2018-04-25 9:48 ` Jan Beulich
2018-04-25 10:06 ` Wei Liu
2018-04-25 10:26 ` Jan Beulich
2018-04-25 10:31 ` Wei Liu
2018-04-25 10:35 ` Olaf Hering
2018-04-25 10:47 ` Wei Liu
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