From: anupam.kapoor@gmail.com (anupam kapoor)
To: kernelnewbies@lists.kernelnewbies.org
Subject: What happens when an interrupt comes while in middle of printk?
Date: Wed, 25 Feb 2015 11:08:39 +0530 [thread overview]
Message-ID: <87y4nm7dpc.fsf@fatcat.parallelwireless> (raw)
In-Reply-To: <CAB6A5-ApwcFhvo-vUGJwsRuLXaxeC5FN_cC8JwLyCfALBnLZUg@mail.gmail.com>
>>>>> [2015-02-25T08:37:59+0530]: "manty kuma" (manty-kuma):
,----[ manty-kuma ]
| What happens if an interrupt comes while in middle of printk execution and
| the interrupt handler has a printk in it?
|
| There is a chance that the log_buf could be corrupted. isn't it?
`----
no this doesn't happen. look at vprintk_emit(...) which invokes
local_irq_save(...).
essentially, printk tries to acquire console_lock. if it succeeds all is
well. otherwise, output is dumped to a log buffer. when the current
holder of console_lock, unlocks it, log buffer is emptied...
---
thanks
anupam
prev parent reply other threads:[~2015-02-25 5:38 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-25 3:07 What happens when an interrupt comes while in middle of printk? manty kuma
2015-02-25 3:41 ` greg.freemyer at gmail.com
2015-02-25 3:47 ` nick
2015-02-25 5:38 ` anupam kapoor [this message]
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