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FAILED: patch "[PATCH] powerpc/64s: Disable STRICT_KERNEL_RWX" failed to apply to 5.4-stable tree

PATCH [email protected] 2 participants 3 messages May 23, 2020

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author maintainer
#0 lore raw

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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8659a0e0efdd975c73355dbc033f79ba3b31e82c Mon Sep 17 00:00:00 2001
From: Michael Ellerman <[email protected]>
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 [email protected] # v4.13+
Signed-off-by Michael Ellerman <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
arch/powerpc/Kconfig +1 -1
index 924c541a9260..d13b5328ca10 100644
@@ -130,7 +130,7 @@ config PPC
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_MEMBARRIER_CALLBACKS
 	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_UACCESS_FLUSHCACHE
 	select ARCH_HAS_UACCESS_MCSAFE		if PPC64
maintainer
#1 lore raw
Quoted 30 lines · On Sat, May 23, 2020 at 02:13:35PM +0200, [email protected] 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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8659a0e0efdd975c73355dbc033f79ba3b31e82c Mon Sep 17 00:00:00 2001
From: Michael Ellerman <[email protected]>
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.

Quoted 7 lines

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 [email protected] # v4.13+
Signed-off-by Michael Ellerman <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here

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.

Signature · 2 lines
Thanks,
Sasha
author maintainer
#2 lore raw
Quoted 34 lines · Sasha Levin
Quoted 33 lines · On Sat, May 23, 2020 at 02:13:35PM +0200, [email protected] 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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 8659a0e0efdd975c73355dbc033f79ba3b31e82c Mon Sep 17 00:00:00 2001

From: Michael Ellerman <[email protected]>
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.

Quoted 8 lines
Quoted 4 lines
Fixes 1e0fc9d1eb2b ("powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs")
Cc [email protected] # v4.13+
Signed-off-by Michael Ellerman <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here

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!