This is a note to let you know that I've just added the patch titled
KVM: x86: Cancel pvclock_gtod_work on module removal
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-cancel-pvclock_gtod_work-on-module-removal.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 594b27e677b35f9734b1969d175ebc6146741109 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Date: Wed, 5 May 2021 23:48:17 +0200
Subject: KVM: x86: Cancel pvclock_gtod_work on module removal
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
commit 594b27e677b35f9734b1969d175ebc6146741109 upstream.
Nothing prevents the following:
pvclock_gtod_notify()
queue_work(system_long_wq, &pvclock_gtod_work);
...
remove_module(kvm);
...
work_queue_run()
pvclock_gtod_work() <- UAF
Ditto for any other operation on that workqueue list head which touches
pvclock_gtod_work after module removal.
Cancel the work in kvm_arch_exit() to prevent that.
Fixes: 16e8d74d2da9 ("KVM: x86: notifier for clocksource changes")
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Message-Id: <87czu4onry.ffs@xxxxxxxxxxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 1 +
1 file changed, 1 insertion(+)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7356,6 +7356,7 @@ void kvm_arch_exit(void)
cpuhp_remove_state_nocalls(CPUHP_AP_X86_KVM_CLK_ONLINE);
#ifdef CONFIG_X86_64
pvclock_gtod_unregister_notifier(&pvclock_gtod_notifier);
+ cancel_work_sync(&pvclock_gtod_work);
#endif
kvm_x86_ops = NULL;
kvm_mmu_module_exit();
Patches currently in stable-queue which might be from tglx@xxxxxxxxxxxxx are
queue-5.4/kvm-x86-cancel-pvclock_gtod_work-on-module-removal.patch
