This is a note to let you know that I've just added the patch titled x86/xen: Remove undefined behavior in setup_features() 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: x86-xen-remove-undefined-behavior-in-setup_features.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 2d161481def0d608648b7f5bc2167ef75ef567e9 Author: Julien Grall <jgrall@xxxxxxxxxx> Date: Fri Jun 17 11:30:37 2022 +0100 x86/xen: Remove undefined behavior in setup_features() [ Upstream commit ecb6237fa397b7b810d798ad19322eca466dbab1 ] 1 << 31 is undefined. So switch to 1U << 31. Fixes: 5ead97c84fa7 ("xen: Core Xen implementation") Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx> Reviewed-by: Juergen Gross <jgross@xxxxxxxx> Link: https://lore.kernel.org/r/20220617103037.57828-1-julien@xxxxxxx Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/xen/features.c b/drivers/xen/features.c index 7b591443833c..87f1828d40d5 100644 --- a/drivers/xen/features.c +++ b/drivers/xen/features.c @@ -42,7 +42,7 @@ void xen_setup_features(void) if (HYPERVISOR_xen_version(XENVER_get_features, &fi) < 0) break; for (j = 0; j < 32; j++) - xen_features[i * 32 + j] = !!(fi.submap & 1<<j); + xen_features[i * 32 + j] = !!(fi.submap & 1U << j); } if (xen_pv_domain()) {