Re: tg3 BUG: spinlock lockup suspected

[Meelis Roos]

> Can you please share the Linux Distribution information along with sparc machine specification.

Sun Fire V210 (dual UltraSPARC IIIi), onboard NICs with tg3 
driver. Debian unstable snapshot (as last seen in Debian):

deb http://snapshot.debian.org/archive/debian/20150725T121538Z/ unstable main contrib non-free

except for udev and libudev1 that are 218-8 (older) because the latest 
udev at that moment was broken.

This implies gcc version 4.9.3 (Debian 4.9.3-2).


> Regards,
> Deepak Khungar
> 
> On Wed, Oct 19, 2016 at 10:18 AM, Siva Reddy Kallam <siva.kallam@xxxxxxxxxxxx> wrote:
>       On Mon, Oct 17, 2016 at 6:35 PM, Meelis Roos <mroos@xxxxxxxx> wrote:
>       >> > Now I reproduced the bug even with 4.7-rc1 so it is older than 4.7. Will
>       >> > test further.
>       >>
>       >> It gets stranger and stranger - my old 4.7 image worked fine, freshly
>       >> compiled 4.7 exhibits the same problem.
>       >>
>       >> Toolchain has not changed, that I know for sure.
>       >>
>       >> What may have changed is kernel .config. My old conf was with whatever I
>       >> had during 4.7. Then I upgraded to 4.8-rc3 and then 4.8 and selected
>       >> values for "make oldconfig" new entries. Then went back to 4.7-rc1 and
>       >> then to 4.7 with this config, answering quiestion about new options when
>       >> any appeared. Diff is not available since I do not have the old configs
>       >> archived.
>       >
>       > I did some more digging. Found an older configuration that is working
>       > and recreated a newer one that is bad, for the same 4.7 kernel. This is
>       > reproducible now, from "make clean" state.
>       >
>       > Working config from 4.7-rc4 attached as config-4.7, broken config from
>       > 4.7 attached as config-4.7-bad.
>       >
>       > Will try to bisect the configs as time permits. But looking at the
>       > stack traces, the issue is probably timing related, when ip and dhclient
>       > do something with the same lock. seq_read that outputs stats could be
>       > reading /proc/net/dev that reads counters from each interface.
>       >
>       > ifupdown seems to use the following for dhcp interfaces:
>       >   up
>       >     [[/bin/ip link set dev %iface% address %hwaddress%]]
>       >     /sbin/dhclient -v -pf /run/dhclient.%iface%.pid -lf /var/lib/dhcp/dhclient.%iface%.leases -I -df /var/lib/dhcp/dhclient6.%iface%.leases %iface% \
>       > ...
>       >
>       > so ip link is setting link up, this creates some work for the
>       > background, and the dhclient goes adn reads /proc/net/dev, and lockup is
>       > suspected but not proven?
>       >
>       > I started a loop for test, doing cat /proc/net/dev in a loop and at the
>       > same link link up and down from console, but up and down is slow process
>       > and the loop did not seem to trigger the warning over night, so it was
>       > not so simple.
>       >
>       I am busy with other priority tasks. One of my colleague Deepak will
>       work this with you.
>       I added him to CC list.
>       Thanks.
>       >
>       >> > > [   83.716570] BUG: spinlock lockup suspected on CPU#0, dhclient/1014
>       >> > > [   83.797819]  lock: 0xfff000123c8e4a08, .magic: dead4ead, .owner: ip/1001, .owner_cpu: 1
>       >> > > [   83.903130] CPU: 0 PID: 1014 Comm: dhclient Not tainted 4.8.0 #4
>       >> > > [   83.982129] Call Trace:
>       >> > > [   84.014160]  [00000000004b7220] spin_dump+0x60/0xa0
>       >> > > [   84.078203]  [00000000004b73a0] do_raw_spin_lock+0xa0/0x120
>       >> > > [   84.106344] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
>       >> > > [   84.107193] ip (1001) used greatest stack depth: 2168 bytes left
>       >> > > [   84.306955]  [000000000092c0d0] _raw_spin_lock_bh+0x30/0x40
>       >> > > [   84.380188]  [00000000100822cc] tg3_get_stats64+0xc/0x80 [tg3]
>       >> > > [   84.456885]  [00000000007fac8c] dev_get_stats+0x2c/0xc0
>       >> > > [   84.525506]  [000000000081a4e8] dev_seq_printf_stats+0x8/0xe0
>       >> > > [   84.600986]  [000000000081a5e4] dev_seq_show+0x24/0x40
>       >> > > [   84.668467]  [00000000005cb6c4] seq_read+0x2c4/0x440
>       >> > > [   84.733656]  [000000000060b97c] proc_reg_read+0x3c/0x80
>       >> > > [   84.802282]  [00000000005a219c] __vfs_read+0x1c/0x140
>       >> > > [   84.868613]  [00000000005a2310] vfs_read+0x50/0x100
>       >> > > [   84.932662]  [00000000005a265c] SyS_read+0x3c/0xa0
>       >> > > [   84.995573]  [00000000004061d4] linux_sparc_syscall32+0x34/0x60
>       >> > > [   85.073748] * CPU[  0]: TSTATE[00000044f0001a22] TPC[00000000f79a16b0] TNPC[00000000f79a16b4] TASK[dhclient:1014]
>       >> > > [   85.208732]              TPC[f79a16b0] O7[f79405c8] I7[0] RPC[0]
>       >> > > [   85.287633]   CPU[  1]: TSTATE[0000004480001605] TPC[00000000004b26f0] TNPC[00000000004d0b0c] TASK[swapper/1:0]
>       >> > > [   85.420338]              TPC[trace_hardirqs_off+0x10/0x20] O7[rcu_idle_enter+0x64/0xa0] I7[cpu_startup_entry+0x1b0/0x240] RPC[rest_init+0x178/0x1a0]
>       >> > > [   85.664600] tg3 0000:00:02.0 eth0: Link is up at 100 Mbps, full duplex
>       >> > > [   85.750515] tg3 0000:00:02.0 eth0: Flow control is off for TX and off for RX
>       >> > > [   85.843994] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
>       >
>       > --
>       > Meelis Roos (mroos@xxxxxxxx)
> 
> 
> 
> 

-- 
Meelis Roos (mroos@xxxxx)      http://www.cs.ut.ee/~mroos/