lockdep warnings in ipv6
From: Jan Engelhardt
Date: Sun Feb 24 2008 - 07:11:53 EST
Hi,
when doing IPv6 (ping6, ssh otherhost, etc.), lockdep spews a warning in
2.6.25-rc2 on the target. CONFIG_..._FRAME_POINTER is off,
CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER=y
# CONFIG_FRAME_POINTER is not set
so I am not sure if the stack trace is worth something, is it?
[ 449.168320] =======================================================
[ 449.168637] [ INFO: possible circular locking dependency detected ]
[ 449.168851] 2.6.25-rc2 #67
[ 449.168951] -------------------------------------------------------
[ 449.169078] swapper/0 is trying to acquire lock:
[ 449.169315] (&tbl->lock){-+-+}, at: [<c023d5a3>]
neigh_lookup+0x43/0xb0
[ 449.170147]
[ 449.170150] but task is already holding lock:
[ 449.170309] (&n->lock){-+-+}, at: [<c023f975>]
neigh_timer_handler+0x15/0x2a0
[ 449.170512]
[ 449.170514] which lock already depends on the new lock.
[ 449.170516]
[ 449.170736]
[ 449.170738] the existing dependency chain (in reverse order) is:
[ 449.170926]
[ 449.170927] -> #1 (&n->lock){-+-+}:
[ 449.171188] [<c0132266>] add_lock_to_list+0x46/0xc0
[ 449.171509] [<c0134c48>] __lock_acquire+0xb48/0xf90
[ 449.171678] [<c023dcda>] neigh_periodic_timer+0x7a/0x170
[ 449.171849] [<c01350ef>] lock_acquire+0x5f/0x80
[ 449.172007] [<c023dcda>] neigh_periodic_timer+0x7a/0x170
[ 449.172173] [<c029b239>] _write_lock+0x29/0x40
[ 449.172342] [<c023dcda>] neigh_periodic_timer+0x7a/0x170
[ 449.172508] [<c023dcda>] neigh_periodic_timer+0x7a/0x170
[ 449.172670] [<c011dd5f>] run_timer_softirq+0x15f/0x1c0
[ 449.172984] [<c023dc60>] neigh_periodic_timer+0x0/0x170
[ 449.173180] [<c023dc60>] neigh_periodic_timer+0x0/0x170
[ 449.173349] [<c011a182>] __do_softirq+0x52/0xb0
[ 449.173516] [<c011a225>] do_softirq+0x45/0x50
[ 449.173675] [<c011a665>] irq_exit+0x55/0x70
[ 449.173831] [<c0104e83>] do_IRQ+0x43/0x90
[ 449.173987] [<c0103214>] common_interrupt+0x24/0x40
[ 449.174147] [<c010321e>] common_interrupt+0x2e/0x40
[ 449.174308] [<ffffffff>] 0xffffffff
[ 449.174767]
[ 449.174769] -> #0 (&tbl->lock){-+-+}:
[ 449.174939] [<c01324f0>] print_circular_bug_entry+0x40/0x50
[ 449.175108] [<c0134a71>] __lock_acquire+0x971/0xf90
[ 449.175268] [<c013425e>] __lock_acquire+0x15e/0xf90
[ 449.175468] [<c0133c16>] trace_hardirqs_on+0x66/0x110
[ 449.175633] [<c01350ef>] lock_acquire+0x5f/0x80
[ 449.175793] [<c023d5a3>] neigh_lookup+0x43/0xb0
[ 449.175973] [<c029b2fe>] _read_lock_bh+0x2e/0x40
[ 449.176139] [<c023d5a3>] neigh_lookup+0x43/0xb0
[ 449.176303] [<c023d5a3>] neigh_lookup+0x43/0xb0
[ 449.177821] [<c8a74a8c>] ndisc_dst_alloc+0x13c/0x1a0 [ipv6]
[ 449.177821] [<c8a74950>] ndisc_dst_alloc+0x0/0x1a0 [ipv6]
[ 449.177821] [<c8a78575>] __ndisc_send+0x95/0x4e0 [ipv6]
[ 449.177821] [<c8a67410>] ip6_output+0x0/0xb00 [ipv6]
[ 449.177821] [<c8a79467>] ndisc_send_ns+0x67/0xa0 [ipv6]
[ 449.177821] [<c8a6eeb0>] ipv6_chk_addr+0xa0/0xb0 [ipv6]
[ 449.177821] [<c8a7a4ef>] ndisc_solicit+0x9f/0x1b0 [ipv6]
[ 449.177821] [<c0133af8>] mark_held_locks+0x38/0x70
[ 449.177821] [<c029b665>] _spin_unlock_irqrestore+0x45/0x60
[ 449.177821] [<c0133c16>] trace_hardirqs_on+0x66/0x110
[ 449.177821] [<c023fab5>] neigh_timer_handler+0x155/0x2a0
[ 449.177821] [<c011dd5f>] run_timer_softirq+0x15f/0x1c0
[ 449.177821] [<c023f960>] neigh_timer_handler+0x0/0x2a0
[ 449.177821] [<c023f960>] neigh_timer_handler+0x0/0x2a0
[ 449.177821] [<c011a182>] __do_softirq+0x52/0xb0
[ 449.177821] [<c011a225>] do_softirq+0x45/0x50
[ 449.177821] [<c011a665>] irq_exit+0x55/0x70
[ 449.177821] [<c0104e83>] do_IRQ+0x43/0x90
[ 449.177821] [<c0103214>] common_interrupt+0x24/0x40
[ 449.177821] [<c010321e>] common_interrupt+0x2e/0x40
[ 449.177821] [<c0101ace>] default_idle+0x5e/0x90
[ 449.177821] [<c0101a70>] default_idle+0x0/0x90
[ 449.177821] [<c0101910>] cpu_idle+0x30/0x80
[ 449.177821] [<ffffffff>] 0xffffffff
[ 449.177821]
[ 449.177821] other info that might help us debug this:
[ 449.177821]
[ 449.177821] 1 lock held by swapper/0:
[ 449.177821] #0: (&n->lock){-+-+}, at: [<c023f975>]
neigh_timer_handler+0x15/0x2a0
[ 449.177821]
[ 449.177821] stack backtrace:
[ 449.177821] Pid: 0, comm: swapper Not tainted 2.6.25-rc2 #67
[ 449.177821] [<c0132d72>] print_circular_bug_tail+0x72/0x80
[ 449.177821] [<c0134a71>] __lock_acquire+0x971/0xf90
[ 449.177821] [<c013425e>] __lock_acquire+0x15e/0xf90
[ 449.177821] [<c0133c16>] trace_hardirqs_on+0x66/0x110
[ 449.177821] [<c01350ef>] lock_acquire+0x5f/0x80
[ 449.177821] [<c023d5a3>] neigh_lookup+0x43/0xb0
[ 449.177821] [<c029b2fe>] _read_lock_bh+0x2e/0x40
[ 449.177821] [<c023d5a3>] neigh_lookup+0x43/0xb0
[ 449.177821] [<c023d5a3>] neigh_lookup+0x43/0xb0
[ 449.177821] [<c8a74a8c>] ndisc_dst_alloc+0x13c/0x1a0 [ipv6]
[ 449.177821] [<c8a74950>] ndisc_dst_alloc+0x0/0x1a0 [ipv6]
[ 449.177821] [<c8a78575>] __ndisc_send+0x95/0x4e0 [ipv6]
[ 449.177821] [<c8a67410>] ip6_output+0x0/0xb00 [ipv6]
[ 449.177821] [<c8a79467>] ndisc_send_ns+0x67/0xa0 [ipv6]
[ 449.177821] [<c8a6eeb0>] ipv6_chk_addr+0xa0/0xb0 [ipv6]
[ 449.177821] [<c8a7a4ef>] ndisc_solicit+0x9f/0x1b0 [ipv6]
[ 449.177821] [<c0133af8>] mark_held_locks+0x38/0x70
[ 449.177821] [<c029b665>] _spin_unlock_irqrestore+0x45/0x60
[ 449.177821] [<c0133c16>] trace_hardirqs_on+0x66/0x110
[ 449.177821] [<c023fab5>] neigh_timer_handler+0x155/0x2a0
[ 449.177821] [<c011dd5f>] run_timer_softirq+0x15f/0x1c0
[ 449.177821] [<c023f960>] neigh_timer_handler+0x0/0x2a0
[ 449.177821] [<c023f960>] neigh_timer_handler+0x0/0x2a0
[ 449.177821] [<c011a182>] __do_softirq+0x52/0xb0
[ 449.177821] [<c011a225>] do_softirq+0x45/0x50
[ 449.177821] [<c011a665>] irq_exit+0x55/0x70
[ 449.177821] [<c0104e83>] do_IRQ+0x43/0x90
[ 449.177821] [<c0103214>] common_interrupt+0x24/0x40
[ 449.177821] [<c010321e>] common_interrupt+0x2e/0x40
[ 449.177821] [<c0101ace>] default_idle+0x5e/0x90
[ 449.177821] [<c0101a70>] default_idle+0x0/0x90
[ 449.177821] [<c0101910>] cpu_idle+0x30/0x80
[ 449.177821] =======================
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