Messages in this thread | | | Subject | Re: lockdep warning after recent cleanup in console code | From | Andy Shevchenko <> | Date | Wed, 30 Apr 2014 11:12:53 +0300 |
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On Tue, 2014-04-29 at 23:07 +0200, Jan Kara wrote: > On Tue 29-04-14 11:38:04, Andy Shevchenko wrote: > > On Mon, 2014-04-28 at 21:24 +0200, Jan Kara wrote: > > > On Mon 28-04-14 14:14:39, Steven Rostedt wrote: > > > > On Mon, 28 Apr 2014 19:51:39 +0200 > > > > Jan Kara <jack@suse.cz> wrote: > > > > > > > > > On Mon 28-04-14 13:43:31, Steven Rostedt wrote: > > > > > > Things have changed with regard to printk() in linux-next. Now it > > > > > > appears that lockdep is going haywire over it. I don't understand the > > > > > > exact reason for the lockdep_off() and lockdep_on() logic that is in > > > > > > printk(), but it obviously seems to be causing issues with the new > > > > > > changes. > > > > > > > > > > > > Care to take a look? > > > > > The obvious cause is that I moved lockdep_on() somewhat earlier in > > > > > vprintk_emit() so lockdep now covers more of printk code. And apparently > > > > > something is wrong there... > > > > > > > > > > > > > Exactly, and I rather know *exactly* what is wrong before we just start > > > > throwing patches at the problem and hope it goes away. That's not how > > > > to solve a software bug. > > > So I had a look and we are missing mutex_release() in > > > console_trylock_for_printk() if we don't have a console to print to. > > > Attached patch should fix the problem. > > > > Besides it doesn't apply clearly on top of today's linux-next, it > > doesn't fix the issue, but modifies it a bit. > Sorry, I was too tired and missed conversion of one place. Attached is a > new version of the patch which also applies cleanly against linux-next.
Either you decide to revert, not apply or leave as is that patch that prevents to apply clearly, this one seems good.
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
-- Andy Shevchenko <andriy.shevchenko@linux.intel.com> Intel Finland Oy
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