hi, Suren Baghdasaryan,
On Sun, Dec 08, 2024 at 06:09:05PM -0800, Suren Baghdasaryan wrote:
> On Sun, Dec 8, 2024 at 7:26 AM kernel test robot <oliver.sang@xxxxxxxxx> wrote:
> >
> >
> >
> > Hello,
> >
> > kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:
> >
> > commit: 85ad413389aec04cfaaba043caa8128b76c6e491 ("mm: make vma cache SLAB_TYPESAFE_BY_RCU")
> > https://git.kernel.org/cgit/linux/kernel/git/akpm/mm.git mm-unstable
> >
> > in testcase: boot
> >
> > config: i386-randconfig-141-20241208
> > compiler: gcc-11
> > test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
> >
> > (please refer to attached dmesg/kmsg for entire log/backtrace)
> >
> >
> > +------------------------------------------------+------------+------------+
> > | | 98d5eefb97 | 85ad413389 |
> > +------------------------------------------------+------------+------------+
> > | BUG:kernel_NULL_pointer_dereference,address | 0 | 12 |
> > | Oops | 0 | 12 |
> > | EIP:lock_anon_vma_root | 0 | 12 |
> > | Kernel_panic-not_syncing:Fatal_exception | 0 | 12 |
> > +------------------------------------------------+------------+------------+
> >
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
> > | Closes: https://lore.kernel.org/oe-lkp/202412082208.db1fb2c9-lkp@xxxxxxxxx
>
> Thanks for the report!
> It looks like anon_vma passed to lock_anon_vma_root() is NULL but it's
> not obvious to me why my patch would cause that.
>
> Oliver, how can I reproduce this locally?
>
To reproduce:
# build kernel
cd linux
cp config-6.13.0-rc1-00162-g85ad413389ae .config
make -j$(nproc) HOSTCC=gcc-11 CC=gcc-11 ARCH=i386 olddefconfig prepare modules_prepare bzImage modules
make -j$(nproc) HOSTCC=gcc-11 CC=gcc-11 ARCH=i386 INSTALL_MOD_PATH=<mod-install-dir> modules_install
cd <mod-install-dir>
find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz
git clone https://github.com/intel/lkp-tests.git
cd lkp-tests
bin/lkp qemu -k <bzImage> -m modules.cgz job-script # job-script is attached in this email
# if come across any failure that blocks the test,
# please remove ~/.lkp and /lkp dir to run from a clean state.
config and job-script files are attached in original report.
one thing we want to mention is this seems only reproducible with i386 config in
our tests.
