diff mbox

KVM: arm/arm64: Stop leaking vcpu pid references

Message ID 1465403085-2358-1-git-send-email-james.morse@arm.com (mailing list archive)
State New, archived
Headers show

Commit Message

James Morse June 8, 2016, 4:24 p.m. UTC 
kvm provides kvm_vcpu_uninit(), which amongst other things, releases the
last reference to the struct pid of the task that was last running the vcpu.

On arm64 built with CONFIG_DEBUG_KMEMLEAK, starting a guest with kvmtool,
then killing it with SIGKILL results (after some considerable time) in:
> cat /sys/kernel/debug/kmemleak
> unreferenced object 0xffff80007d5ea080 (size 128):
>  comm "lkvm", pid 2025, jiffies 4294942645 (age 1107.776s)
>  hex dump (first 32 bytes):
>    01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>  backtrace:
>    [<ffff8000001b30ec>] create_object+0xfc/0x278
>    [<ffff80000071da34>] kmemleak_alloc+0x34/0x70
>    [<ffff80000019fa2c>] kmem_cache_alloc+0x16c/0x1d8
>    [<ffff8000000d0474>] alloc_pid+0x34/0x4d0
>    [<ffff8000000b5674>] copy_process.isra.6+0x79c/0x1338
>    [<ffff8000000b633c>] _do_fork+0x74/0x320
>    [<ffff8000000b66b0>] SyS_clone+0x18/0x20
>    [<ffff800000085cb0>] el0_svc_naked+0x24/0x28
>    [<ffffffffffffffff>] 0xffffffffffffffff

On x86 kvm_vcpu_uninit() is called on the path from kvm_arch_destroy_vm(),
on arm no equivalent call is made. Add the call to kvm_arch_vcpu_free().

Signed-off-by: James Morse <james.morse@arm.com>
Fixes: 749cf76c5a36 ("KVM: ARM: Initial skeleton to compile KVM support")
Cc: <stable@vger.kernel.org> # 3.10+
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm/kvm/arm.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Christoffer Dall June 27, 2016, 11:08 a.m. UTC | #1 
On Wed, Jun 08, 2016 at 05:24:45PM +0100, James Morse wrote:
> kvm provides kvm_vcpu_uninit(), which amongst other things, releases the
> last reference to the struct pid of the task that was last running the vcpu.
> 
> On arm64 built with CONFIG_DEBUG_KMEMLEAK, starting a guest with kvmtool,
> then killing it with SIGKILL results (after some considerable time) in:
> > cat /sys/kernel/debug/kmemleak
> > unreferenced object 0xffff80007d5ea080 (size 128):
> >  comm "lkvm", pid 2025, jiffies 4294942645 (age 1107.776s)
> >  hex dump (first 32 bytes):
> >    01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >  backtrace:
> >    [<ffff8000001b30ec>] create_object+0xfc/0x278
> >    [<ffff80000071da34>] kmemleak_alloc+0x34/0x70
> >    [<ffff80000019fa2c>] kmem_cache_alloc+0x16c/0x1d8
> >    [<ffff8000000d0474>] alloc_pid+0x34/0x4d0
> >    [<ffff8000000b5674>] copy_process.isra.6+0x79c/0x1338
> >    [<ffff8000000b633c>] _do_fork+0x74/0x320
> >    [<ffff8000000b66b0>] SyS_clone+0x18/0x20
> >    [<ffff800000085cb0>] el0_svc_naked+0x24/0x28
> >    [<ffffffffffffffff>] 0xffffffffffffffff
> 
> On x86 kvm_vcpu_uninit() is called on the path from kvm_arch_destroy_vm(),
> on arm no equivalent call is made. Add the call to kvm_arch_vcpu_free().
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> Fixes: 749cf76c5a36 ("KVM: ARM: Initial skeleton to compile KVM support")
> Cc: <stable@vger.kernel.org> # 3.10+
> Acked-by: Marc Zyngier <marc.zyngier@arm.com>

Applied, thanks.

-Christoffer
diff mbox

Patch

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 893941ec98dc..f1bde7c4e736 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -263,6 +263,7 @@  void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
 	kvm_timer_vcpu_terminate(vcpu);
 	kvm_vgic_vcpu_destroy(vcpu);
 	kvm_pmu_vcpu_destroy(vcpu);
+	kvm_vcpu_uninit(vcpu);
 	kmem_cache_free(kvm_vcpu_cache, vcpu);
 }