Re: [PATCH v1] mm/gup: remove (VM_)BUG_ONs

[SeongJae Park <sj@kernel.org>]

On Wed,  4 Jun 2025 16:05:44 +0200 David Hildenbrand <david@redhat.com> wrote:

> Especially once we hit one of the assertions in
> sanity_check_pinned_pages(), observing follow-up assertions failing
> in other code can give good clues about what went wrong, so use
> VM_WARN_ON_ONCE instead.
> 
> While at it, let's just convert all VM_BUG_ON to VM_WARN_ON_ONCE as
> well. Add one comment for the pfn_valid() check.
> 
> We have to introduce VM_WARN_ON_ONCE_VMA() to make that fly.
> 
> Drop the BUG_ON after mmap_read_lock_killable(), if that ever returns
> something > 0 we're in bigger trouble. Convert the other BUG_ON's into
> VM_WARN_ON_ONCE as well, they are in a similar domain "should never
> happen", but more reasonable to check for during early testing.
> 
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Mike Rapoport <rppt@kernel.org>
> Cc: Suren Baghdasaryan <surenb@google.com>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Peter Xu <peterx@redhat.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>

Acked-by: SeongJae Park <sj@kernel.org>


Thanks,
SJ

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