Skip to contentSkip to conversation

FAILED: patch "[PATCH] KVM: arm/arm64: Stop leaking vcpu pid references" failed to apply to 3.14-stable tree

PATCH [email protected] 1 participant 1 message Jul 24, 2016

Subsystems (2)
Stable branch Arm (32-bit)
lore
Share & tools
lore

[email protected]

author maintainer
#0 lore raw

The patch below does not apply to the 3.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 591d215afcc2f94e8e2c69a63c924c044677eb31 Mon Sep 17 00:00:00 2001

From: James Morse <[email protected]>
Date: Wed, 8 Jun 2016 17:24:45 +0100
Subject: [PATCH] KVM: arm/arm64: Stop leaking vcpu pid references

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:

Quoted 4 lines

cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff80007d5ea080 (size 128):
comm "lkvm", pid 2025, jiffies 4294942645 (age 1107.776s) hex dump (first 32 bytes):

Quoted 12 lines
   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 <[email protected]>
Fixes 749cf76c5a36 ("KVM: ARM: Initial skeleton to compile KVM support")
Cc <[email protected]> # 3.10+
Acked-by Marc Zyngier <[email protected]>
Signed-off-by Christoffer Dall <[email protected]>
arch/arm/kvm/arm.c +1 -0
index 893941ec98dc..f1bde7c4e736 100644
@@ -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);
 }