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genirq: Properly pair kobject_del() with kobject_add()

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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 aa30f47cf6 ("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: ecb3f394c5 ("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
This commit is contained in:
Michael Kelley 2019-08-01 23:53:53 +00:00 committed by Thomas Gleixner
parent d1abaeb3be
commit d0ff14fdc9
1 changed files with 14 additions and 1 deletions
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15
kernel/irq/irqdesc.c
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@ -295,6 +295,18 @@ static void irq_sysfs_add(int irq, struct irq_desc *desc)
}
}
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;
@ -325,6 +337,7 @@ 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 */
@ -438,7 +451,7 @@ 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);
/*