Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] Assigning DAX_ONLINE_DEFAULT (-1) to enum mmop triggers UBSan out-of-bounds violation. --
commit e0320ba16dade8553731440e4c066c6a7c836047 Author: Gregory Price <[email protected]> dax: plumb hotplug online_type through dax There is no way for drivers leveraging dax_kmem to plumb through a preferred auto-online policy - the system default policy is forced. Add 'enum mmop' field to DAX device creation path to allow drivers to specify an auto-online policy when using the kmem driver. > diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h > index 5909171a4428b..f3c9dae5de6ba 100644 > --- a/drivers/dax/bus.h > +++ b/drivers/dax/bus.h > @@ -16,6 +17,13 @@ struct dax_region; > #define IORESOURCE_DAX_STATIC BIT(0) > #define IORESOURCE_DAX_KMEM BIT(1) > > +/* > + * online_type sentinel: the device was created without an explicit online > + * policy, so the system default is resolved when the kmem driver binds, > + * (not at device-creation time, which would freeze a stale policy). > + */ > +#define DAX_ONLINE_DEFAULT (-1) > + > struct dax_region *alloc_dax_region(struct device *parent, int region_id, > struct range *range, int target_node, unsigned int align, > unsigned long flags); > @@ -26,6 +34,7 @@ struct dev_dax_data { > resource_size_t size; > int id; > bool memmap_on_memory; > + enum mmop online_type; [Severity: Medium] Can this declaration cause an out-of-bounds UBSan violation when assigned DAX_ONLINE_DEFAULT? DAX_ONLINE_DEFAULT is defined as -1, but enum mmop only has a valid range from 0 to 3. > }; [ ... ] > diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h > index 81e4af49e39c1..ccd77965fe3ed 100644 > --- a/drivers/dax/dax-private.h > +++ b/drivers/dax/dax-private.h > @@ -95,6 +98,7 @@ struct dev_dax { > struct device dev; > struct dev_pagemap *pgmap; > bool memmap_on_memory; > + enum mmop online_type; [Severity: Medium] Does this struct member also need to be an int instead of enum mmop to safely store the -1 sentinel value? > int nr_range; > struct dev_dax_range *ranges; > }; [ ... ] > diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c > index 592171ec10f49..0a184c0878ddf 100644 > --- a/drivers/dax/kmem.c > +++ b/drivers/dax/kmem.c > @@ -132,6 +133,11 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) > goto err_reg_mgid; > data->mgid = rc; > > + /* Resolve system default at bind time in case it changed */ > + online_type = dev_dax->online_type; [Severity: Medium] Could loading dev_dax->online_type here when it is set to -1 trigger a UBSan out-of-bounds violation during probe? > + if (online_type == DAX_ONLINE_DEFAULT) > + online_type = mhp_get_default_online_type(); > + -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=6
