Messages in this thread | | | Date | Thu, 28 Sep 2017 20:13:26 +0900 | From | Sergey Senozhatsky <> | Subject | Re: sched: serial port lockdep warning when offlining CPUs |
| |
On (09/28/17 11:04), Levin, Alexander (Sasha Levin) wrote: > On Thu, Sep 28, 2017 at 11:38:47AM +0200, Peter Zijlstra wrote: > >On Thu, Sep 28, 2017 at 02:19:46AM -0700, Sasha Levin wrote: > >> Hi all, > >> > >> I seem to be hitting the following warning when offlining CPUs on the > >> latest -next kernel: > >> > >> [289683102.607076] Unregister pv shared memory for cpu 8 > >> [289683102.622922] select_fallback_rq: 3 callbacks suppressed > > > >This is because you hit a printk() from the scheduler, that's known > >broken (along with the rest of printk). > > > >You forgot to actually include that printk() though I suspect it reads > >like: > > > > "process %d (%s) no longer affine to cpu%d\n" > > > >Now that uses printk_deferred() which _should_ work lots better, but > >clearly the printk() stuff went wobbly again. > > Hm, so is this an actual possible lockup, or just a false positive?
a possible one.
printk() used to lockdep_off()/lockdep_on() in "dangerous places" before, but not anymore.
-ss
| |