Re: [PATCH -next] bcachefs: fix possible null-ptr-deref in __bch2_ec_stripe_head_get()

[Kent Overstreet]

On Sat, Oct 26, 2024 at 06:26:58PM +0800, Gaosheng Cui wrote:
> The function ec_new_stripe_head_alloc() returns nullptr if kzalloc()
> fails. It is crucial to verify its return value before dereferencing
> it to avoid a potential nullptr dereference.
> 
> Fixes: 035d72f72c91 ("bcachefs: bch2_ec_stripe_head_get() now checks for 
> change in rw devices")
> Signed-off-by: Gaosheng Cui <cuigaoshe...@huawei.com>

Thanks, applied

> ---
>  fs/bcachefs/ec.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
> index 25d20f73df60..b24089733467 100644
> --- a/fs/bcachefs/ec.c
> +++ b/fs/bcachefs/ec.c
> @@ -1859,6 +1859,10 @@ __bch2_ec_stripe_head_get(struct btree_trans *trans,
>               }
>  
>       h = ec_new_stripe_head_alloc(c, disk_label, algo, redundancy, 
> watermark);
> +     if (!h) {
> +             h = ERR_PTR(-ENOMEM);
> +             goto err;
> +     }
>  found:
>       if (h->rw_devs_change_count != c->rw_devs_change_count)
>               ec_stripe_head_devs_update(c, h);
> -- 
> 2.25.1
>