Commit 8659a0e0 authored by Michael Ellerman's avatar Michael Ellerman

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: 1e0fc9d1 ("powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs")
Cc: stable@vger.kernel.org # v4.13+
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200520133605.972649-1-mpe@ellerman.id.au
parent 40bb0e90
...@@ -130,7 +130,7 @@ config PPC ...@@ -130,7 +130,7 @@ config PPC
select ARCH_HAS_PTE_SPECIAL select ARCH_HAS_PTE_SPECIAL
select ARCH_HAS_MEMBARRIER_CALLBACKS select ARCH_HAS_MEMBARRIER_CALLBACKS
select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE && PPC_BOOK3S_64 select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE && PPC_BOOK3S_64
select ARCH_HAS_STRICT_KERNEL_RWX if ((PPC_BOOK3S_64 || PPC32) && !HIBERNATION) select ARCH_HAS_STRICT_KERNEL_RWX if (PPC32 && !HIBERNATION)
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_UACCESS_FLUSHCACHE select ARCH_HAS_UACCESS_FLUSHCACHE
select ARCH_HAS_UACCESS_MCSAFE if PPC64 select ARCH_HAS_UACCESS_MCSAFE if PPC64
......
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