linux-kernel - Re: [PATCH v2 3/3] mm: vmalloc: Replace BUG_ON() by WARN_ON

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Date:   Wed, 21 Dec 2022 19:13:03 +0000
From:   Lorenzo Stoakes <lstoakes@...il.com>
To:     "Uladzislau Rezki (Sony)" <urezki@...il.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        LKML <linux-kernel@...r.kernel.org>, Baoquan He <bhe@...hat.com>,
        Christoph Hellwig <hch@...radead.org>,
        Matthew Wilcox <willy@...radead.org>,
        Nicholas Piggin <npiggin@...il.com>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...y.com>
Subject: Re: [PATCH v2 3/3] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE()

On Wed, Dec 21, 2022 at 06:44:54PM +0100, Uladzislau Rezki (Sony) wrote:
> Currently a vm_unmap_ram() functions triggers a BUG() if an area
> is not found. Replace it by the WARN_ON_ONCE() error message and
> keep machine alive instead of stopping it.
>
> The worst case is a memory leaking.
>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
> ---
>  mm/vmalloc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 17e688cc7357..221d8950e13c 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2252,7 +2252,9 @@ void vm_unmap_ram(const void *mem, unsigned int count)
>  	}
>
>  	va = find_unlink_vmap_area(addr);
> -	BUG_ON(!va);
> +	if (WARN_ON_ONCE(!va))
> +		return;
> +
>  	debug_check_no_locks_freed((void *)va->va_start,
>  				    (va->va_end - va->va_start));
>  	free_unmap_vmap_area(va);
> --
> 2.30.2
>
Reviewed-by: Lorenzo Stoakes <lstoakes@...il.com>