On Thu, Sep 24, 2020 at 09:08:57AM -0700, Joe Perches wrote: > On Thu, 2020-09-24 at 12:28 +0200, Peter Zijlstra wrote: > > On Mon, Sep 21, 2020 at 06:22:12PM +0200, Daniel Bristot de Oliveira wrote: > > > While testing hotplug I got this BUG: > > > It was caused by printk() inside a code section protected by a > > > raw_spin_lock() that ended up calling a serial console that > > > uses a regular spin_lock(). > > > > > > Use the printk_deferred() to avoid calling the serial console > > > in a raw_spin_lock() protected section. > > > > I consider printk_deferred() to be a bug, can't we just wait for the new > > printk implementation to land so we don't need all this nonsense? > > It will be good to do a sed fixup for all these > printk_deferred uses soon, but in the meantime > isn't it useful to avoid BUGs?
The kernel isn't PROVE_RAW_LOCK_NESTING clean anyway. Printk is one of the biggest offenders there anyway, iirc.
