Re: [PATCH 1/2] bpf: classify block device hooks appropriately

[Christoph Hellwig]

On Fri, Feb 20, 2026 at 06:48:48PM +0100, Christian Brauner wrote:
> A bunch of new hooks for managing block devices were added a while ago
> but they weren't actually appropriately classified.

> 
> * bpf_lsm_bdev_alloc() is called when the inode for the block
>   device is allocated. This happens from a sleepable context so mark the
>   function as sleepable. When this function is called the memory for the
>   block device storage embedded into the inode is zeroed. That block
>   device cannot be meaningfully reference or interacted with at this
>   point. So mark it as untrusted for now.
> 
> * bpf_lsm_bdev_free() is called when the inode for the block
>   device is freed. A bunch of memory associated with the block device
>   has already been freed and there's dangling pointers in there. So mark
>   it as untrusted. It cannot be meaningfully referenced or interacted
>   with anymore. It is also called from sb->s_op->free_inode:: which
>   means it runs in rcu context (most of the times). So leave it as
>   non-sleepable.

How did this even get added?  None of this should be of any business
to LSM hooks :(