WTF: patch "[PATCH] x86: kvm: avoid unused variable warning" was seriously submitted to be applied to the 4.18-stable tree?

PATCH [email protected] 3 participants 5 messages Sep 2, 2018 – Sep 13, 2018

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[email protected]

author maintainer

2018-09-02 01:44 UTC #0 lore raw

The patch below was submitted to be applied to the 4.18-stable tree.

I fail to see how this patch meets the stable kernel rules as found at Documentation/process/stable-kernel-rules.rst.

I could be totally wrong, and if so, please respond to <[email protected]> and let me know why this patch should be applied. Otherwise, it is now dropped from my patch queues, never to be seen again.

thanks,

greg k-h

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

Quoted 1 line

From 7288bde1f9df6c1475675419bdd7725ce84dec56 Mon Sep 17 00:00:00 2001

From: Arnd Bergmann <[email protected]>
Date: Mon, 20 Aug 2018 23:37:50 +0200
Subject: [PATCH] x86: kvm: avoid unused variable warning

Removing one of the two accesses of the maxphyaddr variable led to a harmless warning:

arch/x86/kvm/x86.c: In function 'kvm_set_mmio_spte_mask':
arch/x86/kvm/x86.c:6563:6: error: unused variable 'maxphyaddr' [-Werror=unused-variable]

Removing the #ifdef seems to be the nicest workaround, as it makes the code look cleaner than adding another #ifdef.

Fixes 28a1f3ac1d0c ("kvm: x86: Set highest physical address bits in non-present/reserved SPTEs")

Signed-off-by Arnd Bergmann <[email protected]>

Cc [email protected] # L1TF

Signed-off-by Paolo Bonzini <[email protected]>

arch/x86/kvm/x86.c +1 -3

index f7dff0457846..14ee9a814888 100644
@@ -6576,14 +6576,12 @@ static void kvm_set_mmio_spte_mask(void)
 	/* Set the present bit. */
 	mask |= 1ull;
 
-#ifdef CONFIG_X86_64
 	/*
 	 * If reserved bit is not supported, clear the present bit to disable
 	 * mmio page fault.
 	 */
-	if (maxphyaddr == 52)
+	if (IS_ENABLED(CONFIG_X86_64) && maxphyaddr == 52)
 		mask &= ~1ull;
-#endif
 
 	kvm_mmu_set_mmio_spte_mask(mask, mask);
 }

Greg KH

author maintainer

2018-09-02 01:52 UTC #1 lore raw

Quoted 4 lines · On Sat, Sep 01, 2018 at 02:24:23PM -0700, [email protected] wrote:

The patch below was submitted to be applied to the 4.18-stable tree.
I fail to see how this patch meets the stable kernel rules as found at Documentation/process/stable-kernel-rules.rst.

Oops, hit the wrong button, this should have been my "this did not apply" message, sorry about that.

This doesn't apply because:

Quoted 20 lines

I could be totally wrong, and if so, please respond to <[email protected]> and let me know why this patch should be applied. Otherwise, it is now dropped from my patch queues, never to be seen again.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
Quoted 1 line
From 7288bde1f9df6c1475675419bdd7725ce84dec56 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <[email protected]>
Date: Mon, 20 Aug 2018 23:37:50 +0200
Subject: [PATCH] x86: kvm: avoid unused variable warning
Removing one of the two accesses of the maxphyaddr variable led to a harmless warning:

Quoted 7 lines

arch/x86/kvm/x86.c: In function 'kvm_set_mmio_spte_mask':
arch/x86/kvm/x86.c:6563:6: error: unused variable 'maxphyaddr' [-Werror=unused-variable]
Removing the #ifdef seems to be the nicest workaround, as it makes the code look cleaner than adding another #ifdef.
Fixes 28a1f3ac1d0c ("kvm: x86: Set highest physical address bits in non-present/reserved SPTEs")

that commit is not in a stable tree. It wasn't marked to be backpoted, should it?

thanks,

greg k-h

Arnd Bergmann

2018-09-03 13:47 UTC #2 lore raw

Quoted 10 lines · Greg KH

Quoted 4 lines · On Sat, Sep 01, 2018 at 02:24:23PM -0700, [email protected] wrote:
The patch below was submitted to be applied to the 4.18-stable tree.
I fail to see how this patch meets the stable kernel rules as found at Documentation/process/stable-kernel-rules.rst.
Oops, hit the wrong button, this should have been my "this did not apply" message, sorry about that.

Quoted 7 lines

This doesn't apply because:
Quoted 2 lines
Fixes 28a1f3ac1d0c ("kvm: x86: Set highest physical address bits in non-present/reserved SPTEs")
that commit is not in a stable tree. It wasn't marked to be backpoted, should it?

When I sent my compile fix, I did not expect either one to need a backport. Looking at 28a1f3ac1d0c more closely does make it sound like it should be. Junaid Shahid wrote the patch originally, let's see what he thinks.

Arnd

Junaid Shahid

2018-09-04 23:44 UTC #3 lore raw

Quoted 16 lines · Arnd Bergmann

Quoted 15 lines · Greg KH
Quoted 4 lines · On Sat, Sep 01, 2018 at 02:24:23PM -0700, [email protected] wrote:
The patch below was submitted to be applied to the 4.18-stable tree.
I fail to see how this patch meets the stable kernel rules as found at Documentation/process/stable-kernel-rules.rst.
Oops, hit the wrong button, this should have been my "this did not apply" message, sorry about that.
This doesn't apply because:
Quoted 2 lines
Fixes 28a1f3ac1d0c ("kvm: x86: Set highest physical address bits in non-present/reserved SPTEs")

Quoted 9 lines

Quoted 2 lines
that commit is not in a stable tree. It wasn't marked to be backpoted, should it?
When I sent my compile fix, I did not expect either one to need a backport. Looking at 28a1f3ac1d0c more closely does make it sound like it should be. Junaid Shahid wrote the patch originally, let's see what he thinks.
Arnd

Yes, I think that it would be a good idea to include 28a1f3ac1d0c in the stable tree, as it contains a security fix related to L1TF.

Thanks,
Junaid

gregkh

author maintainer

2018-09-13 12:27 UTC #4 lore raw

Quoted 20 lines · Junaid Shahid

Quoted 19 lines · Arnd Bergmann
Quoted 17 lines · Greg KH
Quoted 4 lines · On Sat, Sep 01, 2018 at 02:24:23PM -0700, [email protected] wrote:
The patch below was submitted to be applied to the 4.18-stable tree.
I fail to see how this patch meets the stable kernel rules as found at Documentation/process/stable-kernel-rules.rst.
Oops, hit the wrong button, this should have been my "this did not apply" message, sorry about that.
This doesn't apply because:
Quoted 2 lines
Fixes 28a1f3ac1d0c ("kvm: x86: Set highest physical address bits in non-present/reserved SPTEs")
that commit is not in a stable tree. It wasn't marked to be backpoted, should it?

Quoted 8 lines

Quoted 6 lines
When I sent my compile fix, I did not expect either one to need a backport. Looking at 28a1f3ac1d0c more closely does make it sound like it should be. Junaid Shahid wrote the patch originally, let's see what he thinks.
Arnd
Yes, I think that it would be a good idea to include 28a1f3ac1d0c in the stable tree, as it contains a security fix related to L1TF.

Ok, now applied to 4.18.y and 4.14.y, thanks.

greg k-h