On 2020/4/17 1:23, Marc Zyngier wrote:
On 2020-04-16 02:17, Zenghui Yu wrote:
On 2020/4/14 11:03, Zenghui Yu wrote:
If we're going to fail out the vgic_add_lpi(), let's make sure the
allocated vgic_irq memory is also freed. Though it seems that both
cases are unlikely to fail.
Cc: Zengruan Ye <yezengruan@xxxxxxxxxx>
Signed-off-by: Zenghui Yu <yuzenghui@xxxxxxxxxx>
---
virt/kvm/arm/vgic/vgic-its.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index d53d34a33e35..3c3b6a0f2dce 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -98,12 +98,16 @@ static struct vgic_irq *vgic_add_lpi(struct kvm
*kvm, u32 intid,
* the respective config data from memory here upon mapping the
LPI.
*/
ret = update_lpi_config(kvm, irq, NULL, false);
- if (ret)
+ if (ret) {
+ kfree(irq);
return ERR_PTR(ret);
+ }
ret = vgic_v3_lpi_sync_pending_status(kvm, irq);
- if (ret)
+ if (ret) {
+ kfree(irq);
return ERR_PTR(ret);
+ }
Looking at it again, I realized that this error handling is still not
complete. Maybe we should use a vgic_put_irq() instead so that we can
also properly delete the vgic_irq from lpi_list.
Yes, this is a more correct fix indeed. There is still a bit of a bizarre
behaviour if you have two vgic_add_lpi() racing to create the same
interrupt,
which is pretty dodgy anyway (it means we have two MAPI at the same
time...).
You end-up with re-reading the state from memory... Oh well.
Marc, what do you think? Could you please help to fix it, or I can
resend it.
I've fixed it as such (with a comment for a good measure):
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 3c3b6a0f2dce..c012a52b19f5 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -96,16 +96,19 @@ static struct vgic_irq *vgic_add_lpi(struct kvm
*kvm, u32 intid,
* We "cache" the configuration table entries in our struct
vgic_irq's.
* However we only have those structs for mapped IRQs, so we read in
* the respective config data from memory here upon mapping the LPI.
+ *
+ * Should any of these fail, behave as if we couldn't create the LPI
+ * by dropping the refcount and returning the error.
*/
ret = update_lpi_config(kvm, irq, NULL, false);
if (ret) {
- kfree(irq);
+ vgic_put_irq(kvm, irq);
return ERR_PTR(ret);
}
ret = vgic_v3_lpi_sync_pending_status(kvm, irq);
if (ret) {
- kfree(irq);
+ vgic_put_irq(kvm, irq);
return ERR_PTR(ret);
}
Let me know if you agree with that.
Agreed. Thanks for the fix!
Zenghui
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
