Re: [PATCH] mm/madvise: handle madvise_lock() failure during race unwinding

[David Hildenbrand <david@redhat.com>]

On 02.06.25 19:49, SeongJae Park wrote:
> When unwinding race on -ERESTARTNOINTR handling of process_madvise(),
> madvise_lock() failure is ignored.  Check the failure and abort
> remaining works in the case.
> 
> Fixes: 4000e3d0a367 ("mm/madvise: remove redundant mmap_lock operations from process_madvise()")
> Cc: stable@kernel.org
> Reported-by: Barry Song <21cnbao@gmail.com>
> Closes: https://lore.kernel.org/CAGsJ_4xJXXO0G+4BizhohSZ4yDteziPw43_uF8nPXPWxUVChzw@mail.gmail.com
> Signed-off-by: SeongJae Park <sj@kernel.org>
> ---
>   mm/madvise.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 8433ac9b27e0..5f7a66a1617e 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -1881,7 +1881,9 @@ static ssize_t vector_madvise(struct mm_struct *mm, struct iov_iter *iter,
>   			/* Drop and reacquire lock to unwind race. */
>   			madvise_finish_tlb(&madv_behavior);
>   			madvise_unlock(mm, behavior);
> -			madvise_lock(mm, behavior);
> +			ret = madvise_lock(mm, behavior);
> +			if (ret)
> +				goto out;
>   			madvise_init_tlb(&madv_behavior, mm);
>   			continue;
>   		}
> @@ -1892,6 +1894,7 @@ static ssize_t vector_madvise(struct mm_struct *mm, struct iov_iter *iter,
>   	madvise_finish_tlb(&madv_behavior);
>   	madvise_unlock(mm, behavior);
>   
> +out:
>   	ret = (total_len - iov_iter_count(iter)) ? : ret;

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb