From: Marc Zyngier maz@kernel.org
commit 47e6223c841e029bfc23c3ce594dac5525cebaf8 upstream.
Booting a KVM host in protected mode with kmemleak quickly results in a pretty bad crash, as kmemleak doesn't know that the HYP sections have been taken away. This is specially true for the BSS section, which is part of the kernel BSS section and registered at boot time by kmemleak itself.
Unregister the HYP part of the BSS before making that section HYP-private. The rest of the HYP-specific data is obtained via the page allocator or lives in other sections, none of which is subjected to kmemleak.
Fixes: 90134ac9cabb ("KVM: arm64: Protect the .hyp sections from the host") Reviewed-by: Quentin Perret qperret@google.com Reviewed-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Marc Zyngier maz@kernel.org Cc: stable@vger.kernel.org # 5.13 Link: https://lore.kernel.org/r/20210802123830.2195174-3-maz@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kvm/arm.c | 7 +++++++ 1 file changed, 7 insertions(+)
--- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -15,6 +15,7 @@ #include <linux/fs.h> #include <linux/mman.h> #include <linux/sched.h> +#include <linux/kmemleak.h> #include <linux/kvm.h> #include <linux/kvm_irqfd.h> #include <linux/irqbypass.h> @@ -1957,6 +1958,12 @@ static int finalize_hyp_mode(void) if (ret) return ret;
+ /* + * Exclude HYP BSS from kmemleak so that it doesn't get peeked + * at, which would end badly once the section is inaccessible. + * None of other sections should ever be introspected. + */ + kmemleak_free_part(__hyp_bss_start, __hyp_bss_end - __hyp_bss_start); ret = pkvm_mark_hyp_section(__hyp_bss); if (ret) return ret;