Re: [PATCH V3] bcache: revert replacing IS_ERR_OR_NULL with IS_ERR again
From: 邹明哲
Date: Wed Nov 27 2024 - 11:22:47 EST
LGTM
reviewed by Mingzhe Zou
Original:
From：Coly Li <colyli@xxxxxxx>
Date：2024-11-27 11:17:01(中国 (GMT+08:00))
To：liequan che <liequanche@xxxxxxxxx>
Cc：mingzhe.zou@xxxxxxxxxxxx<mingzhe.zou@xxxxxxxxxxxx> , Kent Overstreet <kent.overstreet@xxxxxxxxx> , linux-bcache <linux-bcache@xxxxxxxxxxxxxxx> , linux-kernel <linux-kernel@xxxxxxxxxxxxxxx>
Subject：Re: [PATCH V3] bcache: revert replacing IS_ERR_OR_NULL with IS_ERR again
> 2024年11月27日 11:01，liequan che <liequanche@xxxxxxxxx> 写道：
>
> Commit 028ddcac477b ("bcache: Remove unnecessary NULL point check in
> node allocations") leads a NULL pointer deference in cache_set_flush().
>
> 1721 if (!IS_ERR_OR_NULL(c->root))
> 1722 list_add(&c->root->list, &c->btree_cache);
>
> From the above code in cache_set_flush(), if previous registration code
> fails before allocating c->root, it is possible c->root is NULL as what
> it is initialized. Also __bch_btree_node_alloc() never returns NULL but
> c->root is possible to be NULL at above line 1721.
>
> This patch replaces IS_ERR() by IS_ERR_OR_NULL() to fix this.
OK, this time the commit log makes a lot sense. It is clear to me.
>
> Fixes: 028ddcac477b ("bcache: Remove unnecessary NULL point check in
> node allocations")
> Signed-off-by: Liequan Che <cheliequan@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Zheng Wang <zyytlz.wz@xxxxxxx>
> Cc: Coly Li <colyli@xxxxxxx>
> ---
> drivers/md/bcache/super.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index e7abfdd77c3b..e42f1400cea9 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -1718,7 +1718,7 @@ static CLOSURE_CALLBACK(cache_set_flush)
> if (!IS_ERR_OR_NULL(c->gc_thread))
> kthread_stop(c->gc_thread);
>
> - if (!IS_ERR(c->root))
> + if (!IS_ERR_OR_NULL(c->root))
> list_add(&c->root->list, &c->btree_cache);
>
> /*
> —
> 2.46.0
It is fine to me. I am in travel these days, and will handle this patch by end of this week.
Thanks for composing this patch.
Coly Li
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