Commits
Govindarajulu Varadarajan committed b6931c9ba72
enic: fix possible deadlock in enic_stop/ enic_rfs_flw_tbl_free
The following warning is shown when spinlock debug is enabled.
This occurs when enic_flow_may_expire timer function is running and
enic_stop is called on same CPU.
Fix this by using spink_lock_bh().
=================================
[ INFO: inconsistent lock state ]
3.17.0-netnext-05504-g59f35b8 #268 Not tainted
---------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
ifconfig/443 [HC0[0]:SC0[0]:HE1:SE1] takes:
(&(&enic->rfs_h.lock)->rlock){+.?...}, at:
enic_rfs_flw_tbl_free+0x34/0xd0 [enic]
{IN-SOFTIRQ-W} state was registered at:
[<ffffffff810a25af>] __lock_acquire+0x83f/0x21c0
[<ffffffff810a45f2>] lock_acquire+0xa2/0xd0
[<ffffffff814913fc>] _raw_spin_lock+0x3c/0x80
[<ffffffffa029c3d5>] enic_flow_may_expire+0x25/0x130[enic]
[<ffffffff810bcd07>] call_timer_fn+0x77/0x100
[<ffffffff810bd8e3>] run_timer_softirq+0x1e3/0x270
[<ffffffff8105f9ae>] __do_softirq+0x14e/0x280
[<ffffffff8105fdae>] irq_exit+0x8e/0xb0
[<ffffffff8103da0f>] smp_apic_timer_interrupt+0x3f/0x50
[<ffffffff81493742>] apic_timer_interrupt+0x72/0x80
[<ffffffff81018143>] default_idle+0x13/0x20
[<ffffffff81018a6a>] arch_cpu_idle+0xa/0x10
[<ffffffff81097676>] cpu_startup_entry+0x2c6/0x330
[<ffffffff8103b7ad>] start_secondary+0x21d/0x290
irq event stamp: 2997
hardirqs last enabled at (2997): [<ffffffff81491865>] _raw_spin_unlock_irqrestore+0x65/0x90
hardirqs last disabled at (2996): [<ffffffff814915e6>] _raw_spin_lock_irqsave+0x26/0x90
softirqs last enabled at (2968): [<ffffffff813b57a3>] dev_deactivate_many+0x213/0x260
softirqs last disabled at (2966): [<ffffffff813b5783>] dev_deactivate_many+0x1f3/0x260
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&(&enic->rfs_h.lock)->rlock);
<Interrupt>
lock(&(&enic->rfs_h.lock)->rlock);
*** DEADLOCK ***
Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>