Re: [PATCH rdma-next 2/2] RDMA/core: Don't warn on oversized bundle allocations

[sashiko-bot@kernel.org]

> From: Uri Dar <udar@nvidia.com>
> 
> _uverbs_alloc() serves requests that do not fit in the bundle's internal
> buffer from kvmalloc(), prepending a small list header. The requested
> size can be derived from userspace input, and since commit 7661809d493b
> ("mm: don't allow oversized kvmalloc() calls") kvmalloc() WARNs on any
> request above INT_MAX unless __GFP_NOWARN is given.
> 
> mlx5 DEVX UMEM registration is one such caller: its CREATE_UMEM mailbox
> scales with the size of the user's UMEM, and a mailbox that passes the
> driver's INT_MAX check can still exceed INT_MAX once the header is
> added.
> 
> As with memdup_user(), an allocation sized by userspace should fail
> quietly rather than warn. Pass __GFP_NOWARN so such requests fail with
> -ENOMEM.
> 
> Fixes: 461bb2eee4e1 ("IB/uverbs: Add a simple allocator to uverbs_attr_bundle")
> Signed-off-by: Uri Dar <udar@nvidia.com>
> Signed-off-by: Edward Srouji <edwards@nvidia.com>

Sashiko has reviewed this patch and found no issues.

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