This is a note to let you know that I've just added the patch titled
arm/xen: fix xen_vcpu_info allocation alignment
to the 5.15-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:
arm-xen-fix-xen_vcpu_info-allocation-alignment.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b38c58e955100ede2490e6aa43be8287a02c918e
Author: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Date: Wed Nov 22 15:07:41 2023 -0800
arm/xen: fix xen_vcpu_info allocation alignment
[ Upstream commit 7bf9a6b46549852a37e6d07e52c601c3c706b562 ]
xen_vcpu_info is a percpu area than needs to be mapped by Xen.
Currently, it could cross a page boundary resulting in Xen being unable
to map it:
[ 0.567318] kernel BUG at arch/arm64/xen/../../arm/xen/enlighten.c:164!
[ 0.574002] Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
Fix the issue by using __alloc_percpu and requesting alignment for the
memory allocation.
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
Link: https://lore.kernel.org/r/alpine.DEB.2.22.394.2311221501340.2053963@ubuntu-linux-20-04-desktop
Fixes: 24d5373dda7c ("arm/xen: Use alloc_percpu rather than __alloc_percpu")
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 27277d6bbfa5a..59de416c61a30 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -359,7 +359,8 @@ static int __init xen_guest_init(void)
* for secondary CPUs as they are brought up.
* For uniformity we use VCPUOP_register_vcpu_info even on cpu0.
*/
- xen_vcpu_info = alloc_percpu(struct vcpu_info);
+ xen_vcpu_info = __alloc_percpu(sizeof(struct vcpu_info),
+ 1 << fls(sizeof(struct vcpu_info) - 1));
if (xen_vcpu_info == NULL)
return -ENOMEM;
