On 3/11/17 6:33 PM, Yanjun Zhu wrote:
Sorry. I have no test case to show some issue.
But from Linux Kernel Development Second Edition by Robert Love.
Yes I know the book and what the API does :D
Use spin_lock_irq is dangerous since spin_unlock_irq unconditionally
enables interrupts.
We can assume the following scenario:
--->the interrupt is disabled.
spin_lock_irq(lock_ptr); <---this will disable interrupt again
list_del(&ic->ib_node);
spin_unlock_irq(lock_ptr); <---this will enable interrupt
---->the interrupt is enabled.
our code change the state of interrupt. This will make potential risk.
But spin_lock_irqsave/spin_unlock_irqrestore will not make potential risk.
ic is well protected for any possible race and hence I asked
if you had any test case. Please re-post the series again with
the subject patch dropper for Dave to pick it up.
Regards,
Santosh
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