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Date: Wed, 27 Jul 2016 10:16:38 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: David Woodhouse <dwmw2@infradead.org>
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On (07/27/16 01:03), David Woodhouse wrote:
[..]
> And if you spew *everything* on panic to a limited output like the
> bootx or VGA text-mode console, you might find that the KERN_DEBUG
> messages obscure what actually happened, which would be visible if you
> only printed KERN_NOTICE and above...

yes, limited output is a problem on its own. sometimes backtrace is just too
big and even critical messages don't fit. I ended up once forcing panic() to
re-print that "bug at __FILE__, __LINE__, __func__" at the bottom of panic
output. schematically, something like this:

 #define BUG() do { \
-       printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
-       panic("BUG!"); \
+       panic("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
 } while (0)

and pr_emerg() that string in panic() instead of atomic_notifier_call_chain()
output.

	-ss