[BUG]: Kernel 4.9: Kernel crash at fs/sysfs/file.c : sysfs_kf_seq_show

[Greg Kroah-Hartman]

On Wed, Jan 13, 2021 at 05:35:18PM +0530, Pintu Agarwal wrote:
> On Tue, 12 Jan 2021 at 17:39, Greg Kroah-Hartman
> <gregkh at linuxfoundation.org> wrote:
> >
> > On Tue, Jan 12, 2021 at 05:31:54PM +0530, Pintu Agarwal wrote:
> > > Hi,
> > >
> > > I am using Kernel: 4.9.217 for one of the ARM32 boards for Qualcomm SOC.
> > > https://github.com/android-linux-stable/msm-4.9
> > >
> > > But I think this is a general bug applicable to :Kernel 4.9 under
> > > fs/sysfs/file.c
> > > So, I wanted to quickly check here if others are familiar with this
> > > issue and if it is fixed already.
> > > Note, this issue does not occur in 4.14 Kernel.
> > >
> > > When I execute below command, the Kernel is crashing.
> > > I tried to add few debug prints to find more details. I see that the
> > > ops->show pointer is not valid (seems corrupted).
> > > So I wanted to understand how this can happen only for this particular node.
> > > Other sysfs entries are working fine.
> > >
> 
> I see that this issue was reported earlier as well by others.
> https://syzkaller.appspot.com/bug?id=2ec2a9da5c711df3d3d12071bac487b96e75e103
> https://gitlab.freedesktop.org/drm/amd/-/issues/413
> https://bugzilla.redhat.com/show_bug.cgi?id=1615070
> 
> So it seems to be common issue and thus I wanted to check here if its similar.

It's "common" in that this is core kernel code that any number of
drivers could be causing to work incorrectly.  Try fixing up the driver
code, and odds are, that will fix this issue.

good luck, and again, go ask for support from your vendor, you are
paying for that!

greg k-h