The recent switch to per-domain locking caused a NULL dereference in
irq_domain_create_hierarchy(), as Xen code is calling
msi_create_irq_domain() with a NULL parent pointer.
Fix that by testing parent to be set before dereferencing it. For a
non-existing parent the irq-domain's root will stay to point to
itself.
Fixes: 9dbb8e3452ab ("irqdomain: Switch to per-domain locking")
Signed-off-by: Juergen Gross <[email protected]>
---
kernel/irq/irqdomain.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index aa5b7eeeceb8..6522dfb2e49c 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1172,7 +1172,8 @@ struct irq_domain *irq_domain_create_hierarchy(struct irq_domain *parent,
domain = __irq_domain_create(fwnode, 0, ~0, 0, ops, host_data);
if (domain) {
- domain->root = parent->root;
+ if (parent)
+ domain->root = parent->root;
domain->parent = parent;
domain->flags |= flags;
--
2.35.3
The following commit has been merged into the irq/urgent branch of tip:
Commit-ID: ad32ab9604f29827494024828f527228e84fbd2c
Gitweb: https://git.kernel.org/tip/ad32ab9604f29827494024828f527228e84fbd2c
Author: Juergen Gross <[email protected]>
AuthorDate: Thu, 23 Feb 2023 09:38:00 +01:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Thu, 23 Feb 2023 15:52:28 +01:00
irqdomain: Add missing NULL pointer check in irq_domain_create_hierarchy()
The recent switch to per-domain locking caused a NULL dereference in
irq_domain_create_hierarchy(), as Xen code is calling
msi_create_irq_domain() with a NULL parent pointer.
Fix that by testing parent to be set before dereferencing it. For a
non-existing parent the irqdomain's root will stay to point to
itself.
Fixes: 9dbb8e3452ab ("irqdomain: Switch to per-domain locking")
Signed-off-by: Juergen Gross <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
kernel/irq/irqdomain.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index aa5b7ee..6522dfb 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1172,7 +1172,8 @@ struct irq_domain *irq_domain_create_hierarchy(struct irq_domain *parent,
domain = __irq_domain_create(fwnode, 0, ~0, 0, ops, host_data);
if (domain) {
- domain->root = parent->root;
+ if (parent)
+ domain->root = parent->root;
domain->parent = parent;
domain->flags |= flags;
On Thu, Feb 23, 2023 at 09:38:00AM +0100, Juergen Gross wrote:
> The recent switch to per-domain locking caused a NULL dereference in
> irq_domain_create_hierarchy(), as Xen code is calling
> msi_create_irq_domain() with a NULL parent pointer.
This was unexpected. Apparently the Intel VMD driver also does this (see
vmd_enable_domain()).
> Fix that by testing parent to be set before dereferencing it. For a
> non-existing parent the irq-domain's root will stay to point to
> itself.
An alternative could be to have msi_create_irq_domain() handle the
no-parent case explicitly, but this looks the right fix for now (e.g. as
irq_domain_create_tree() does not take a flag parameter).
> Fixes: 9dbb8e3452ab ("irqdomain: Switch to per-domain locking")
> Signed-off-by: Juergen Gross <[email protected]>
> ---
> kernel/irq/irqdomain.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
> index aa5b7eeeceb8..6522dfb2e49c 100644
> --- a/kernel/irq/irqdomain.c
> +++ b/kernel/irq/irqdomain.c
> @@ -1172,7 +1172,8 @@ struct irq_domain *irq_domain_create_hierarchy(struct irq_domain *parent,
> domain = __irq_domain_create(fwnode, 0, ~0, 0, ops, host_data);
>
> if (domain) {
> - domain->root = parent->root;
> + if (parent)
> + domain->root = parent->root;
> domain->parent = parent;
> domain->flags |= flags;
Reviewed-by: Johan Hovold <[email protected]>
Johan