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SubjectRe: [PATCH] mpt2sas: prevent double free on error path
Date
Jörn Engel <joern@logfs.org> writes:

> diff --git a/drivers/scsi/mpt2sas/mpt2sas_scsih.c b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
> index c6bdc92..43b3a98 100644
> --- a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
> +++ b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
> @@ -570,6 +570,18 @@ _scsih_sas_device_find_by_handle(struct MPT2SAS_ADAPTER *ioc, u16 handle)
> return NULL;
> }
>
> +static void free_sas_device(struct kref *kref)
> +{
> + struct _sas_device *sas_device = container_of(kref, struct _sas_device,
> + kref);
> + kfree(sas_device);
> +}
> +
> +static void put_sas_device(struct _sas_device *sas_device)
> +{
> + kref_put(&sas_device->kref, free_sas_device);
> +}
> +
> /**
> * _scsih_sas_device_remove - remove sas_device from list.
> * @ioc: per adapter object
> @@ -583,14 +595,19 @@ _scsih_sas_device_remove(struct MPT2SAS_ADAPTER *ioc,
> struct _sas_device *sas_device)
> {
> unsigned long flags;
> + int was_on_list = 0;
>
> if (!sas_device)
> return;
>
> spin_lock_irqsave(&ioc->sas_device_lock, flags);
> - list_del(&sas_device->list);
> - kfree(sas_device);
> + if (!list_empty(&sas_device->list)) {
> + list_del_init(&sas_device->list);
> + was_on_list = 1;
> + }
> spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
> + if (was_on_list)
> + put_sas_device(sas_device);
> }
>


How about the copy of this code in drivers/scsi/mpt3sas/mpt3sas_scsih.c?
Is that safe, or does it need fixing as well?


Bjørn
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