Re: kernel panic: uvm_fault

[Thomas Klausner <wiz%NetBSD.org@localhost>]

On Mon, Dec 22, 2014 at 03:56:43PM +0000, Robert Swindells wrote:
> 
> Thomas Klausner wrote:
> >On Mon, Dec 22, 2014 at 03:29:58PM +0000, Robert Swindells wrote:
> >> 
> >> Thomas Klausner wrote:
> >> >I had a kernel panic today with a amd64/7.99.3 kernel from Dec 20. The
> >> >last activity I had started was downloading a file from network to an
> >> >NFS directory mounted from a Synology.
> 
> >> It looks the same as the panic you had back in September to me:
> >> 
> >> <http://mail-index.netbsd.org/current-users/2014/09/13/msg025777.html>
> >> 
> >> Can you turn on HW checksumming on this machine ?
> 
> >I've just done that ("ifconfig wm0 tcp4csum ip4csum udp4csum"):
> >
> >wm0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> >	capabilities=7ff80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx>
> >	capabilities=7ff80<TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Rx>
> >	capabilities=7ff80<TCP6CSUM_Tx,UDP6CSUM_Rx,UDP6CSUM_Tx,TSO6>
> >	enabled=3f00<IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx>
> >	enabled=3f00<UDP4CSUM_Rx,UDP4CSUM_Tx>
> >	ec_capabilities=7<VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU>
> >	ec_enabled=0
> >...
> >
> >I had in the back of my memory that hardware checksumming was usually
> >the cause of bugs, not when it's turned off. Am I misremembering?
> 
> Depends on the network controller, wm works well for me with
> everything enabled.
> 
> wm0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         capabilities=7ff80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx>
>         capabilities=7ff80<TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Rx>
>         capabilities=7ff80<TCP6CSUM_Tx,UDP6CSUM_Rx,UDP6CSUM_Tx,TSO6>
>         enabled=7ff80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx>
>         enabled=7ff80<TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Rx>
>         enabled=7ff80<TCP6CSUM_Tx,UDP6CSUM_Rx,UDP6CSUM_Tx,TSO6>
>         ec_capabilities=7<VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU>
>         ec_enabled=0
> 
> I have had similar crashes to you when using sw checksumming on
> amd64, never seen it on i386 or arm.
> 
> There was also this:
> 
> <http://mail-index.netbsd.org/port-sparc64/2014/11/29/msg002298.html>
> 
> I guess we need to add some more KASSERT() checks.

Ok, the Synology installed an opsys update again last night, and a
couple minutes ago I tried writing to a still-mounted file system from
it. And got a panic. From dmesg:

192.168.1.2:/volume1/roms: re-enabling wcc
192.168.1.2:/volume1/video: re-enabling wcc
panic: _bus_virt_to_bus
cpu1: Begin traceback...
vpanic() at netbsd:vpanic+0x13c
snprintf() at netbsd:snprintf
_bus_dma_alloc_bouncebuf() at netbsd:_bus_dma_alloc_bouncebuf
bus_dmamap_load_mbuf() at netbsd:bus_dmamap_load_mbuf+0xf0
wm_nq_start() at netbsd:wm_nq_start+0x1c5
ifq_enqueue() at netbsd:ifq_enqueue+0xae
ether_output() at netbsd:ether_output+0x579
ip_output() at netbsd:ip_output+0xdeb
tcp_output() at netbsd:tcp_output+0x15cf
tcp_send_wrapper() at netbsd:tcp_send_wrapper+0xa2
sosend() at netbsd:sosend+0x712
nfs_send() at netbsd:nfs_send+0x8e
nfs_request() at netbsd:nfs_request+0x39d
nfs_writerpc() at netbsd:nfs_writerpc+0x3b0
nfs_doio() at netbsd:nfs_doio+0x250
nfssvc_iod() at netbsd:nfssvc_iod+0x1a1
cpu1: End traceback...


I had and still have all the checksum options turned on as you
suggested.

wm0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        capabilities=7ff80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx>
        capabilities=7ff80<TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Rx>
        capabilities=7ff80<TCP6CSUM_Tx,UDP6CSUM_Rx,UDP6CSUM_Tx,TSO6>
        enabled=3ff00<IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx,TCP4CSUM_Tx>
        enabled=3ff00<UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Rx,TCP6CSUM_Tx>
        enabled=3ff00<UDP6CSUM_Rx,UDP6CSUM_Tx>
        ec_capabilities=7<VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU>
        ec_enabled=0
 
At least the backtrace looks nfs related this time :)
 Thomas