We are running 3.0.36-rt57 on a powerpc box. During some testing with
heavy loads and interfaces coming up/going down (specifically PPP), we
have run into a case where iptables hangs and cannot be killed. It
requires a reboot to fix the problem.
Connecting the BDI and debugging the kernel, we get:
#0 get_counters (t=0xdd5145a0, counters=0xe3458000)
at include/linux/seqlock.h:66
#1 0xc026b4ac in do_ipt_get_ctl (sk=<value optimized out>,
cmd=<value optimized out>, user=0x10612078, len=<value optimized out>)
at net/ipv4/netfilter/ip_tables.c:918
#2 0xc022226c in nf_sockopt (sk=<value optimized out>, pf=2 '\002',
val=<value optimized out>, opt=<value optimized out>, len=0xdd4c7d4c,
get=1) at net/netfilter/nf_sockopt.c:109
#3 0xc0236b1c in ip_getsockopt (sk=0xdf071480, level=<value optimized out>,
optname=65, optval=0x10612078 <Address 0x10612078 out of bounds>,
optlen=0xbfbe0c2c) at net/ipv4/ip_sockglue.c:1308
#4 0xc02522a8 in raw_getsockopt (sk=0xdf071480, level=<value optimized out>,
optname=<value optimized out>, optval=<value optimized out>,
optlen=<value optimized out>) at net/ipv4/raw.c:811
#5 0xc01f4c38 in sock_common_getsockopt (sock=<value optimized out>,
level=<value optimized out>, optname=<value optimized out>,
optval=<value optimized out>, optlen=<value optimized out>)
at net/core/sock.c:2157
#6 0xc01f2df8 in sys_getsockopt (fd=<value optimized out>, level=0,
optname=65, optval=0x10612078 <Address 0x10612078 out of bounds>,
optlen=0xbfbe0c2c) at net/socket.c:1839
#7 0xc01f45b4 in sys_socketcall (call=15, args=<value optimized out>)
at net/socket.c:2421
It seems to be stuck in __read_seqcount_begin. From include/linux/seqlock.h:
static inline unsigned __read_seqcount_begin(const seqcount_t *s)
{
unsigned ret;
repeat:
ret = ACCESS_ONCE(s->sequence);
if (unlikely(ret & 1)) {
cpu_relax();
<----- It is always here
goto repeat;
}
return ret;
}
I've been scouring the mailing lists and Google searches trying to
find something, but thus far have come up with nothing.
Any tips would be appreciated.
Thanks,
Pete
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