On 11/10/2010 03:02 PM, Ben Greear wrote:
> We started up our strenuous wifi testing again, with this morning's
> wireless-testing
> (plus some of our own non-wifi-related patches).
>
> We have a reproducible kernel hang when attempting to quickly
> create and configure 64 STA interfaces, no encryption, with
> an ath5k NIC.
>
> It appears to me that this may be a general mac80211 deadlock
> from the 'sysrq d' output below.
>
> We'll attempt to reproduce with a lesser-patched wireless-testing
> in the meantime.

We could reproduce it on the less hacked kernel.

I think the attached trace might be more useful.  It shows
the blocked tasks spammage that we saw in an earlier
run.

Thanks,
Ben

>
>
> Nov 10 14:54:33 localhost kernel: SysRq : Show Locks Held
> Nov 10 14:54:33 localhost kernel:
> Nov 10 14:54:33 localhost kernel: Showing all locks held in the system:
> Nov 10 14:54:33 localhost kernel: 3 locks held by kworker/0:0/4:
> Nov 10 14:54:33 localhost kernel: #0: (events){+.+.+.}, at: [<c0446ded>]
> process_one_work+0x13e/0x2bf
> Nov 10 14:54:33 localhost kernel: #1: ((linkwatch_work).work){+.+.+.},
> at: [<c0446ded>] process_one_work+0x13e/0x2bf
> Nov 10 14:54:33 localhost kernel: #2: (rtnl_mutex){+.+.+.}, at:
> [<c070220f>] rtnl_lock+0xf/0x11
> Nov 10 14:54:33 localhost kernel: 1 lock held by ntpd/1675:
> Nov 10 14:54:33 localhost kernel: #0: (rtnl_mutex){+.+.+.}, at:
> [<c070220f>] rtnl_lock+0xf/0x11
> Nov 10 14:54:33 localhost kernel: 1 lock held by bash/2182:
> Nov 10 14:54:33 localhost kernel: #0: (&tty->atomic_read_lock){+.+...},
> at: [<c060f4a5>] n_tty_read+0x1d2/0x5ee
> Nov 10 14:54:33 localhost kernel: 1 lock held by bash/2199:
> Nov 10 14:54:33 localhost kernel: #0: (&tty->atomic_read_lock){+.+...},
> at: [<c060f4a5>] n_tty_read+0x1d2/0x5ee
> Nov 10 14:54:33 localhost kernel: 1 lock held by mingetty/2517:
> Nov 10 14:54:33 localhost kernel: #0: (&tty->atomic_read_lock){+.+...},
> at: [<c060f4a5>] n_tty_read+0x1d2/0x5ee
> Nov 10 14:54:33 localhost kernel: 1 lock held by mingetty/2518:
> Nov 10 14:54:33 localhost kernel: #0: (&tty->atomic_read_lock){+.+...},
> at: [<c060f4a5>] n_tty_read+0x1d2/0x5ee
> Nov 10 14:54:33 localhost kernel: 1 lock held by mingetty/2519:
> Nov 10 14:54:33 localhost kernel: #0: (&tty->atomic_read_lock){+.+...},
> at: [<c060f4a5>] n_tty_read+0x1d2/0x5ee
> Nov 10 14:54:33 localhost kernel: 1 lock held by mingetty/2520:
> Nov 10 14:54:33 localhost kernel: #0: (&tty->atomic_read_lock){+.+...},
> at: [<c060f4a5>] n_tty_read+0x1d2/0x5ee
> Nov 10 14:54:33 localhost kernel: 1 lock held by mingetty/2521:
> Nov 10 14:54:33 localhost kernel: #0: (&tty->atomic_read_lock){+.+...},
> at: [<c060f4a5>] n_tty_read+0x1d2/0x5ee
> Nov 10 14:54:33 localhost kernel: 1 lock held by mingetty/2522:
> Nov 10 14:54:33 localhost kernel: #0: (&tty->atomic_read_lock){+.+...},
> at: [<c060f4a5>] n_tty_read+0x1d2/0x5ee
> Nov 10 14:54:33 localhost kernel: 1 lock held by bash/2679:
> Nov 10 14:54:33 localhost kernel: #0: (&tty->atomic_read_lock){+.+...},
> at: [<c060f4a5>] n_tty_read+0x1d2/0x5ee
> Nov 10 14:54:33 localhost kernel: 3 locks held by kworker/0:3/5698:
> Nov 10 14:54:33 localhost kernel: #0: (events){+.+.+.}, at: [<c0446ded>]
> process_one_work+0x13e/0x2bf
> Nov 10 14:54:33 localhost kernel: #1: (wireless_nlevent_work){+.+.+.},
> at: [<c0446ded>] process_one_work+0x13e/0x2bf
> Nov 10 14:54:33 localhost kernel: #2: (rtnl_mutex){+.+.+.}, at:
> [<c070220f>] rtnl_lock+0xf/0x11
> Nov 10 14:54:33 localhost kernel: 1 lock held by ip/6438:
> Nov 10 14:54:33 localhost kernel: #0: (rtnl_mutex){+.+.+.}, at:
> [<c070f78c>] netlink_dump+0x3a/0x16a
> Nov 10 14:54:33 localhost kernel: 1 lock held by ip/6441:
> Nov 10 14:54:33 localhost kernel: #0: (rtnl_mutex){+.+.+.}, at:
> [<c070220f>] rtnl_lock+0xf/0x11
> Nov 10 14:54:33 localhost kernel: 1 lock held by ip/6442:
> Nov 10 14:54:33 localhost kernel: #0: (rtnl_mutex){+.+.+.}, at:
> [<c070220f>] rtnl_lock+0xf/0x11
> Nov 10 14:54:33 localhost kernel: 1 lock held by iwconfig/6443:
> Nov 10 14:54:33 localhost kernel: #0: (rtnl_mutex){+.+.+.}, at:
> [<c070220f>] rtnl_lock+0xf/0x11
> Nov 10 14:54:33 localhost kernel: 1 lock held by ip/6444:
> Nov 10 14:54:33 localhost kernel: #0: (rtnl_mutex){+.+.+.}, at:
> [<c070220f>] rtnl_lock+0xf/0x11
> Nov 10 14:54:33 localhost kernel: 4 locks held by sh/6449:
> Nov 10 14:54:33 localhost kernel: #0: (&(&i->lock)->rlock){-.-...}, at:
> [<c0631760>] serial8250_interrupt+0x1e/0xe2
> Nov 10 14:54:33 localhost kernel: #1: (&port_lock_key){-.-...}, at:
> [<c06314e6>] serial8250_handle_port+0x10/0x26c
> Nov 10 14:54:33 localhost kernel: #2: (sysrq_key_table_lock){-.....},
> at: [<c061e912>] __handle_sysrq+0x18/0x11d
> Nov 10 14:54:33 localhost kernel: #3: (tasklist_lock){.+.+..}, at:
> [<c0459d53>] debug_show_all_locks+0x43/0x179
>


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com