Re: [PATCH v8] kernel, add panic_on_warn

On Thu, 6 Nov 2014, Vivek Goyal wrote:

On Thu, Nov 06, 2014 at 01:57:36PM -0800, David Rientjes wrote:

[..]

quoted

You see that doing

	if (panic_on_warn) {
		panic_on_warn = 0;
		panic(...);
	}

is racy, I hope.  If two threads WARN() at the same time, then there's 
nothing preventing a double panic() because WARN() itself is not 
serialized against anything.  So both the current comment and your 
suggested revision comment are bogus.

panic() is serialized on panic_lock. So I guess it is fine to hit WARN()
on multiple cpus. Do you see an issue there?

No issue at all, what's completely mysterious is the panic_on_warn = 0 and 
the completely bogus comment that says "prevent further WARN()s from 
panicking the system" when that's racy.  There's no need to clear 
panic_on_warn at all.