On Sat, May 23, 2020 at 10:26:14AM -0400, Sasha Levin wrote:
> On Sat, May 23, 2020 at 02:13:35PM +0200, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
> >
> > The patch below does not apply to the 5.4-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@xxxxxxxxxxxxxxx>.
> >
> > thanks,
> >
> > greg k-h
> >
> > ------------------ original commit in Linus's tree ------------------
> >
> > > From 8659a0e0efdd975c73355dbc033f79ba3b31e82c Mon Sep 17 00:00:00 2001
> > From: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> > Date: Wed, 20 May 2020 23:36:05 +1000
> > Subject: [PATCH] powerpc/64s: Disable STRICT_KERNEL_RWX
> >
> > Several strange crashes have been eventually traced back to
> > STRICT_KERNEL_RWX and its interaction with code patching.
> >
> > Various paths in our ftrace, kprobes and other patching code need to
> > be hardened against patching failures, otherwise we can end up running
> > with partially/incorrectly patched ftrace paths, kprobes or jump
> > labels, which can then cause strange crashes.
> >
> > Although fixes for those are in development, they're not -rc material.
> >
> > There also seem to be problems with the underlying strict RWX logic,
> > which needs further debugging.
> >
> > So for now disable STRICT_KERNEL_RWX on 64-bit to prevent people from
> > enabling the option and tripping over the bugs.
> >
> > Fixes: 1e0fc9d1eb2b ("powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs")
> > Cc: stable@xxxxxxxxxxxxxxx # v4.13+
> > Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> > Link: https://lore.kernel.org/r/20200520133605.972649-1-mpe@xxxxxxxxxxxxxx
>
> I also took c55d7b5e6426 ("powerpc: Remove STRICT_KERNEL_RWX
> incompatibility with RELOCATABLE") as a dependency for 5.4 and 4.19, and
> 4ec591e51a4b ("powerpc: restore alphabetic order in Kconfig") for 4.14.
Thanks!
