Messages in this thread | | | Date | Thu, 3 Feb 2022 12:33:35 +0100 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH] printk: defer_console_output: do not assume interrupts disabled |
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On 2022-02-03 12:35:15 [+0106], John Ogness wrote: > With commit 458df9fd4815 ("printk: remove separate printk_sched > buffers and use printk buf instead") defer_console_output() was > changed to no longer disable interrupts. However, it used the > function __this_cpu_or(), which assumes interrupts disabled. That > also should have been changed to this_cpu_or(). > > Although defer_console_output() is mostly used when interrupts are > disabled, this is not always the case. One example is > get_random_bytes(), which is often called with interrupts enabled.
It is okay for __this_cpu_or() to be invoked with disabled preemption if that is true for all callers. Disabled interrupts or not is not important as long as there are no callers in_irq(). I believe that there are callers in_irq() and therefore this_cpu_or() is correct.
> get_random_bytes() > warn_unseeded_randomness() > printk_deferred() > > Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > Signed-off-by: John Ogness <john.ogness@linutronix.de>
Sebastian
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