[bionic:linux][PATCH 0/2] LP:#1862312 - Segmentation fault (kernel oops) with memory-hotplug in ubuntu_kernel_selftests on Bionic kernel

[Marcelo Henrique Cerri]

I tested it against linux-aws because that was the easiest environment
to reproduce the issues.

The steps I used for that was:

1. Install the kernel from proposed.

2. Clone the kernel repo:

   $ git clone git://git.launchpad.net/~canonical-kernel/ubuntu/+source/linux-aws/+git/bionic source

3. Watch the dmesg:

   $ dmesg -w &

4. Run the memory hotplug kselftest:

   $ cd source
   $ sudo make -C tools/testing/selftests TARGETS=memory-hotplug run_tests

5. A BUG ON will be triggered and the system will become unstable.

The same issue doesn't happen with the patched kernel or with the
version from updates.

On Tue, Feb 11, 2020 at 02:43:57PM -0300, Marcelo Henrique Cerri wrote:
> BugLink: https://bugs.launchpad.net/bugs/1862312
> 
> The backport for upstream commit 381eab4a6ee8 (mm/memory_hotplug: fix
> online/offline_pages called w.o. mem_hotplug_lock) placed the call to
> mem_hotplug_begin() on the wrong location and caused a regression.
> 
> This patch set reverts the original backport and applies the right
> version.
> 
> ---
> David Hildenbrand (1):
>   mm/memory_hotplug: fix online/offline_pages called w.o.
>     mem_hotplug_lock
> 
> Marcelo Henrique Cerri (1):
>   Revert "mm/memory_hotplug: fix online/offline_pages called w.o.
>     mem_hotplug_lock"
> 
>  mm/memory_hotplug.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> -- 
> 2.20.1
> 

-- 
Regards,
Marcelo

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