[lkml]   [2014]   [Jun]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC PATCH 00/11] printk: safe printing in NMI context
On Tue, Jun 10, 2014 at 9:46 AM, Frederic Weisbecker <> wrote:
> There is also a big risk that if we push back this bugfix, nobody will actually do
> that desired rewrite.
> Lets be crazy and Cc Linus on that.

Quite frankly, I hate seeing something like this:

kernel/printk/printk.c | 1218 +++++++++++++++++++++++++----------

for something that is stupid and broken. Printing from NMI context
isn't really supposed to work, and we all *know* it's not supposed to

I'd much rather disallow it, and if there is one or two places that
really want to print a warning and know that they are in NMI context,
have a special workaround just for them, with something that does
*not* try to make printk in general work any better.

Dammit, NMI context is special. I absolutely refuse to buy into the
broken concept that we should make more stuff work in NMI context.
Hell no, we should *not* try to make more crap work in NMI. NMI people
should be careful.

Make a trivial "printk_nmi()" wrapper that tries to do a trylock on
logbuf_lock, and *maybe* the existing sequence of

if (console_trylock_for_printk())

then works for actually triggering the printout. But the wrapper
should be 15 lines of code for "if possible, try to print things", and
*not* a thousand lines of changes.


 \ /
  Last update: 2014-06-10 19:41    [W:0.068 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site