Hi Paul,

On Tue, Nov 16, 2021 at 02:28:41AM -0800, Paul E. McKenney wrote:
> On Tue, Nov 16, 2021 at 02:59:30PM +0800, Carel Si wrote:
> > Hi Paul,
> > 
> > On Fri, Nov 12, 2021 at 03:31:09AM -0800, Paul E. McKenney wrote:
> > > On Fri, Nov 12, 2021 at 04:06:20PM +0800, kernel test robot wrote:
> > > > 
> > > > 
> > > > Greeting,
> > > > 
> > > > FYI, we noticed the following commit (built with gcc-9):
> > > > 
> > > > commit: 7a7becb4d01e99471523ac38adf3ed64f8be092e ("rcu-tasks:  Create per-CPU callback lists")
> > > > https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git dev.2021.11.01a
> > > > 
> > > > in testcase: boot
> > > > 
> > > > on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
> > > > 
> > > > caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
> > > > 
> > > > 
> > > > +-------------------------------------------------------------------------------+------------+------------+
> > > > |                                                                               | f62a1317c8 | 7a7becb4d0 |
> > > > +-------------------------------------------------------------------------------+------------+------------+
> > > > | boot_successes                                                                | 19         | 0          |
> > > > | boot_failures                                                                 | 0          | 19         |
> > > > | BUG:sleeping_function_called_from_invalid_context_at_include/linux/sched/mm.h | 0          | 19         |
> > > > +-------------------------------------------------------------------------------+------------+------------+
> > > 
> > > I have the following fixup patch in -rcu that addresses this problem
> > > for me:  cafffee599ad ("fixup! rcu-tasks:  Create per-CPU callback lists").
> > > Does it fix things for you?
> > 
> > We have tested your fixup patch cafffee599 ("fixup! rcu-tasks:  Create per-CPU 
> > callback lists"), it can fix the issue, thanks!
> 
> Very good, and thank you for testing it!  May I apply your Tested-by
> to the resulting combined commit?
> 
> 04855da2a8a1 ("rcu-tasks:  Create per-CPU callback lists")
> 

Sure, pls use "kernel test robot" name shown as below. Thanks!

Tested-by: kernel test robot <beibei.si@intel.com>

> 							Thanx, Paul
> 
> > ================================================================================
> > compiler/kconfig/rootfs/sleep/tbox_group/testcase:
> >   gcc-9/x86_64-rhel-8.3-func/debian-i386-20191205.cgz/1/vm-snb/boot
> > 
> > commit: 
> >   f62a1317c8 ("EXP i915/gem/dmabuf: add <asm/smp.h> to fix build error") >parent
> >   7a7becb4d0 ("rcu-tasks:  Create per-CPU callback lists")               >fbc
> >   cafffee599 ("fixup! rcu-tasks:  Create per-CPU callback lists")        >fix
> > 
> > f62a1317c8c77960 7a7becb4d01e99471523ac38adf cafffee599ad1f69cc4c2429484 
> > ---------------- --------------------------- --------------------------- 
> >        fail:runs  %reproduction    fail:runs  %reproduction    fail:runs
> >            |             |             |             |             |    
> >            :6          100%           6:6            0%            :6     dmesg.BUG:sleeping_function_called_from_invalid_context_at_include/linux/sched/mm.h
> > 
> >