FAILED: patch "[PATCH] x86/apic: Make x2apic_disable() work correctly" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-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]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 0ecc5be200c84e67114f3640064ba2bae3ba2f5a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024090828-tiny-boggle-b7b4@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

0ecc5be200c8 ("x86/apic: Make x2apic_disable() work correctly")
720a22fd6c1c ("x86/apic: Don't access the APIC when disabling x2APIC")
5a88f354dcd8 ("x86/apic: Split register_apic_address()")
d10a904435fa ("x86/apic: Consolidate boot_cpu_physical_apicid initialization sites") 49062454a3eb ("x86/apic: Rename disable_apic")
bea629d57d00 ("x86/apic: Save the APIC virtual base address")
3adee777ad0d ("x86/smpboot: Remove initial_stack on 64-bit")
94a855111ed9 ("Merge tag 'x86_core_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")

thanks,

greg k-h

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

From 0ecc5be200c84e67114f3640064ba2bae3ba2f5a Mon Sep 17 00:00:00 2001
From: Yuntao Wang <[email protected]>
Date: Tue, 13 Aug 2024 09:48:27 +0800
Subject: [PATCH] x86/apic: Make x2apic_disable() work correctly

x2apic_disable() clears x2apic_state and x2apic_mode unconditionally, even when the state is X2APIC_ON_LOCKED, which prevents the kernel to disable it thereby creating inconsistent state.

Due to the early state check for X2APIC_ON, the code path which warns about a locked X2APIC cannot be reached.

Test for state < X2APIC_ON instead and move the clearing of the state and mode variables to the place which actually disables X2APIC.

[ tglx: Massaged change log. Added Fixes tag. Moved clearing so it's at the
right place for back ports ]

index 66fd4b2a37a3..373638691cd4 100644
@@ -1775,12 +1775,9 @@ static __init void apic_set_fixmap(bool read_apic);
 
 static __init void x2apic_disable(void)
 {
-	u32 x2apic_id, state = x2apic_state;
+	u32 x2apic_id;
 
-	x2apic_mode = 0;
-	x2apic_state = X2APIC_DISABLED;
-
-	if (state != X2APIC_ON)
+	if (x2apic_state < X2APIC_ON)
 		return;
 
 	x2apic_id = read_apic_id();

@@ -1793,6 +1790,10 @@ static __init void x2apic_disable(void)
 	}
 
 	__x2apic_disable();
+
+	x2apic_mode = 0;
+	x2apic_state = X2APIC_DISABLED;
+
 	/*
 	 * Don't reread the APIC ID as it was already done from
 	 * check_x2apic() and the APIC driver still is a x2APIC variant,