From: Michael Kelley <mikelley@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/1564703564-4116-1-git-send-email-mikelley@xxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/irq/irqdesc.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -294,6 +294,18 @@ static void irq_sysfs_add(int irq, struc } } +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; @@ -324,6 +336,7 @@ static struct kobj_type irq_kobj_type = }; static void irq_sysfs_add(int irq, struct irq_desc *desc) {} +static void irq_sysfs_del(struct irq_desc *desc) {} #endif /* CONFIG_SYSFS */ @@ -437,7 +450,7 @@ static void free_desc(unsigned int irq) * 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); /*