On Sun, Jul 30, 2006 at 10:32:10PM -0500, Matt Domsch wrote:

On Sun, Jul 30, 2006 at 03:44:16PM -0700, David Miller wrote:

quoted

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Sat, 29 Jul 2006 14:33:25 +1000

quoted

[IPV6]: Audit all ip6_dst_lookup/ip6_dst_store calls

The current users of ip6_dst_lookup can be divided into two classes:

1) The caller holds no locks and is in user-context (UDP).
2) The caller does not want to lookup the dst cache at all.

The second class covers everyone except UDP because most people do
the cache lookup directly before calling ip6_dst_lookup.  This patch
adds ip6_sk_dst_lookup for the first class.

Similarly ip6_dst_store users can be divded into those that need to
take the socket dst lock and those that don't.  This patch adds
__ip6_dst_store for those (everyone except UDP/datagram) that don't
need an extra lock.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Applied, thanks Herbert.

I applied this on 2.6.18-rc3, and it panics immediately as the first
IPv6 TCP (ssh) session is initiated to the system.

I backed out this patch, and get a somewhat different failure then
with 2.6.18-rc3 plain.  The oops repeat continuously with <EOI> after
each.  Again, this occurs as soon as I start an IPv6 ssh session.

-- 
Matt Domsch
Software Architect
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com

Linux version 2.6.18-rc3 (mdomsch@localhost.localdomain) (gcc version 4.1.1 20060721 (Red Hat 4.1.1-13)) #2 SMP Sun Jul 30 23:06:48 CDT 2006
=================================
[ INFO: inconsistent lock state ]
---------------------------------
inconsistent {softirq-on-W} -> {in-softirq-R} usage.
swapper/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
 (&sk->sk_dst_lock){---?}, at: [<ffffffff80415827>] sk_dst_check+0x26/0x113
{softirq-on-W} state was registered at:
  [<ffffffff802a8231>] lock_acquire+0x4a/0x69
  [<ffffffff802688a1>] _write_lock+0x24/0x31
  [<ffffffff8044d9a4>] inet_bind+0x198/0x20b
  [<ffffffff80412ed4>] sys_bind+0x75/0x9c
  [<ffffffff8026144d>] system_call+0x7d/0x83
irq event stamp: 604084
hardirqs last  enabled at (604084): [<ffffffff8020aab2>] kmem_cache_alloc+0xd3/0xf7
hardirqs last disabled at (604083): [<ffffffff8020aa2a>] kmem_cache_alloc+0x4b/0xf7
softirqs last  enabled at (604026): [<ffffffff8021288d>] __do_softirq+0xec/0xf5
softirqs last disabled at (604029): [<ffffffff802626fa>] call_softirq+0x1e/0x28

other info that might help us debug this:
1 lock held by swapper/0:
 #0:  (slock-AF_INET6){-+..}, at: [<ffffffff883d91df>] tcp_v6_rcv+0x30e/0x76f [ipv6]

stack backtrace:

Call Trace:
 [<ffffffff8026f861>] show_trace+0xae/0x30e
 [<ffffffff8026fad6>] dump_stack+0x15/0x17
 [<ffffffff802a634f>] print_usage_bug+0x259/0x26a
 [<ffffffff802a6b38>] mark_lock+0x1d5/0x3db
 [<ffffffff802a76b8>] __lock_acquire+0x412/0xa18
 [<ffffffff802a8232>] lock_acquire+0x4b/0x69
 [<ffffffff802689b8>] _read_lock+0x28/0x34
 [<ffffffff80415827>] sk_dst_check+0x26/0x113
 [<ffffffff883ba986>] :ipv6:ip6_dst_lookup+0x3a/0x192
 [<ffffffff883d6c2f>] :ipv6:tcp_v6_send_synack+0x185/0x2e4
 [<ffffffff883d7a5a>] :ipv6:tcp_v6_conn_request+0x291/0x2f3
 [<ffffffff802455c2>] tcp_rcv_state_process+0x5f/0xe7c
 [<ffffffff883d7015>] :ipv6:tcp_v6_do_rcv+0x268/0x372
 [<ffffffff883d95f0>] :ipv6:tcp_v6_rcv+0x71f/0x76f
 [<ffffffff883bc48f>] :ipv6:ip6_input+0x223/0x315
 [<ffffffff883bcb3d>] :ipv6:ipv6_rcv+0x254/0x2af
 [<ffffffff80221883>] netif_receive_skb+0x260/0x2dd
 [<ffffffff88194292>] :e1000:e1000_clean_rx_irq+0x423/0x4c2
 [<ffffffff88192752>] :e1000:e1000_clean+0x88/0x17d
 [<ffffffff8020caed>] net_rx_action+0xac/0x1d1
 [<ffffffff80212809>] __do_softirq+0x68/0xf5
 [<ffffffff802626fa>] call_softirq+0x1e/0x28
DWARF2 unwinder stuck at call_softirq+0x1e/0x28
Leftover inexact backtrace:
 <IRQ> [<ffffffff80270b48>] do_softirq+0x39/0x9f
 [<ffffffff802960b6>] irq_exit+0x57/0x59
 [<ffffffff80270cab>] do_IRQ+0xfd/0x107
 [<ffffffff8025b612>] mwait_idle+0x0/0x54
 [<ffffffff80261985>] ret_from_intr+0x0/0xf
 <EOI>

<1>Unable to handle kernel paging request at ffffffff82800000 RIP: 
 [<ffffffff8026fa5c>] show_trace+0x2a9/0x30e
PGD 203027 PUD 205027 PMD 0 
Oops: 0000 [1] SMP 
CPU 0 
Modules linked in: ipv6 ipmi_devintf ipmi_si ipmi_msghandler hidp rfcomm l2cap bluetooth sunrpc ip_conntrack_netbios_ns ipt_REJECT xt_state ip_conntrack nfnetlink xt_tcpudp iptable_filter ip_tables x_tables acpi_cpufreq video sbs i2c_ec i2c_core button battery asus_acpi ac parport_pc lp parport intel_rng e1000 sg ehci_hcd ide_cd cdrom pcspkr serio_raw e752x_edac edac_mc uhci_hcd dm_snapshot dm_zero dm_mirror dm_mod ext3 jbd ata_piix libata sd_mod scsi_mod
Pid: 0, comm: swapper Not tainted 2.6.18-rc3 #2
RIP: 0010:[<ffffffff8026fa5c>]  [<ffffffff8026fa5c>] show_trace+0x2a9/0x30e
RSP: 0018:ffffffff8066a850  EFLAGS: 00010002
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000a4ec
RDX: ffffffff80561e60 RSI: 0000000000000000 RDI: ffffffff8056e020
RBP: ffffffff8066a940 R08: ffffffff8066a5a0 R09: ffffffff802abf75
R10: ffffffff802abf75 R11: 0000000000000000 R12: ffffffff827ffffd
R13: ffffffff8066a860 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffffffff80922000(0000) knlGS:0000000000000000
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: ffffffff82800000 CR3: 0000000072e0b000 CR4: 00000000000006e0
Process swapper (pid: 0, threadinfo ffffffff80952000, task ffffffff80561e60)
Stack:  ffffffff8066a860 0000000080725708 0000000000000000 0000000000000000
 0000000000000000 ffffffff80953ec8 ffffffff8066af80 0000000000000046
 0000000000000000 0000000000000000 0000000000000000 0000000000000000
Call Trace:
 [<ffffffff8026fad6>] dump_stack+0x15/0x17
 [<ffffffff802a634f>] print_usage_bug+0x259/0x26a
 [<ffffffff802a6b38>] mark_lock+0x1d5/0x3db
 [<ffffffff802a76b8>] __lock_acquire+0x412/0xa18
 [<ffffffff802a8232>] lock_acquire+0x4b/0x69
 [<ffffffff802689b8>] _read_lock+0x28/0x34
 [<ffffffff80415827>] sk_dst_check+0x26/0x113
 [<ffffffff883ba986>] :ipv6:ip6_dst_lookup+0x3a/0x192
 [<ffffffff883d6c2f>] :ipv6:tcp_v6_send_synack+0x185/0x2e4
 [<ffffffff883d7a5a>] :ipv6:tcp_v6_conn_request+0x291/0x2f3
 [<ffffffff802455c2>] tcp_rcv_state_process+0x5f/0xe7c
 [<ffffffff883d7015>] :ipv6:tcp_v6_do_rcv+0x268/0x372
 [<ffffffff883d95f0>] :ipv6:tcp_v6_rcv+0x71f/0x76f
 [<ffffffff883bc48f>] :ipv6:ip6_input+0x223/0x315
 [<ffffffff883bcb3d>] :ipv6:ipv6_rcv+0x254/0x2af
 [<ffffffff80221883>] netif_receive_skb+0x260/0x2dd
 [<ffffffff88194292>] :e1000:e1000_clean_rx_irq+0x423/0x4c2
 [<ffffffff88192752>] :e1000:e1000_clean+0x88/0x17d
 [<ffffffff8020caed>] net_rx_action+0xac/0x1d1
 [<ffffffff80212809>] __do_softirq+0x68/0xf5
 [<ffffffff802626fa>] call_softirq+0x1e/0x28
DWARF2 unwinder stuck at call_softirq+0x1e/0x28
Leftover inexact backtrace:
 <IRQ> [<ffffffff80270b48>] do_softirq+0x39/0x9f
 [<ffffffff802960b6>] irq_exit+0x57/0x59
 [<ffffffff80270cab>] do_IRQ+0xfd/0x107
 [<ffffffff8025b612>] mwait_idle+0x0/0x54
 [<ffffffff80261985>] ret_from_intr+0x0/0xf
 <EOI>