genirq: Properly pair kobject_del() with kobject_add()
commit d0ff14fdc987303aeeb7de6f1bd72c3749ae2a9b upstream.
If alloc_descs() fails before irq_sysfs_init() has run, free_desc() in the
cleanup path will call kobject_del() even though the kobject has not been
added with kobject_add().
Fix this by making the call to kobject_del() conditional on whether
irq_sysfs_init() has run.
This problem surfaced because commit aa30f47cf666 ("kobject: Add support
for default attribute groups to kobj_type") makes kobject_del() stricter
about pairing with kobject_add(). If the pairing is incorrrect, a WARNING
and backtrace occur in sysfs_remove_group() because there is no parent.
[ tglx: Add a comment to the code and make it work with CONFIG_SYSFS=n ]
Fixes: ecb3f394c5db ("genirq: Expose interrupt information through sysfs")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1564703564-4116-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 5e0ea17..8847f27 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -267,6 +267,18 @@
}
}
+static void irq_sysfs_del(struct irq_desc *desc)
+{
+ /*
+ * If irq_sysfs_init() has not yet been invoked (early boot), then
+ * irq_kobj_base is NULL and the descriptor was never added.
+ * kobject_del() complains about a object with no parent, so make
+ * it conditional.
+ */
+ if (irq_kobj_base)
+ kobject_del(&desc->kobj);
+}
+
static int __init irq_sysfs_init(void)
{
struct irq_desc *desc;
@@ -297,6 +309,7 @@
};
static void irq_sysfs_add(int irq, struct irq_desc *desc) {}
+static void irq_sysfs_del(struct irq_desc *desc) {}
#endif /* CONFIG_SYSFS */
@@ -406,7 +419,7 @@
* The sysfs entry must be serialized against a concurrent
* irq_sysfs_init() as well.
*/
- kobject_del(&desc->kobj);
+ irq_sysfs_del(desc);
delete_irq_desc(irq);
/*