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| author | David S. Miller <davem@davemloft.net> | 2008-03-28 01:42:50 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-03-28 01:42:50 +0100 |
| commit | 50fd4407b8bfbde7c1a0bfe4f24de7df37164342 (patch) | |
| tree | 57a9f05b130903fb2c6c12412352928bb24dc3a7 | |
| parent | [NETFILTER]: Replate direct proc_fops assignment with proc_create call. (diff) | |
| download | linux-50fd4407b8bfbde7c1a0bfe4f24de7df37164342.tar.xz linux-50fd4407b8bfbde7c1a0bfe4f24de7df37164342.zip | |
[NET]: Use local_irq_{save,restore}() in napi_complete().
Based upon a lockdep report.
Since ->poll() can be invoked from netpoll with interrupts
disabled, we must not unconditionally enable interrupts
in napi_complete().
Instead we must use local_irq_{save,restore}().
Noticed by Peter Zijlstra:
<irqs disabled>
netpoll_poll()
poll_napi()
spin_trylock(&napi->poll_lock)
poll_one_napi()
napi->poll() := sky2_poll()
napi_complete()
local_irq_disable()
local_irq_enable() <--- *BUG*
<irq>
irq_exit()
do_softirq()
net_rx_action()
spin_lock(&napi->poll_lock) <--- Deadlock!
Because we still hold the lock....
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/netdevice.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index a2f003239c85..fae6a7ececdb 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -383,9 +383,11 @@ static inline void __napi_complete(struct napi_struct *n) static inline void napi_complete(struct napi_struct *n) { - local_irq_disable(); + unsigned long flags; + + local_irq_save(flags); __napi_complete(n); - local_irq_enable(); + local_irq_restore(flags); } /** |