linux-kernel - Re: [PATCH] atm: idt77252: fix kmemleak when rmmod idt77252

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Message-ID: <20230319002843.GA158280@electric-eye.fr.zoreil.com>
Date:   Sun, 19 Mar 2023 01:28:43 +0100
From:   Francois Romieu <romieu@...zoreil.com>
To:     Li Zetao <lizetao1@...wei.com>
Cc:     3chas3@...il.com, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] atm: idt77252: fix kmemleak when rmmod idt77252

Li Zetao <lizetao1@...wei.com> :
> There are memory leaks reported by kmemleak:
[...]
> diff --git a/drivers/atm/idt77252.c b/drivers/atm/idt77252.c
> index eec0cc2144e0..060f32b0def3 100644
> --- a/drivers/atm/idt77252.c
> +++ b/drivers/atm/idt77252.c
[...]
> @@ -2952,6 +2953,16 @@ open_card_ubr0(struct idt77252_dev *card)
>  	return 0;
>  }
>  
> +static void
> +close_card_ubr0(struct idt77252_dev *card)
> +{
> +	struct vc_map *vc;
> +
> +	vc = card->vcs[0];

Nit:
+	struct vc_map *vc = card->vcs[0];

I have not found any opportunity for a double free related to the patch.

So, other than the nit above:

Reviewed-by: Francois Romieu <romieu@...zoreil.com>

FWIW
- the driver leaks on error in open_card_ubr0.
- some forward declarations (alloc_scq, free_scq, etc.) are useless.
- struct idt77252_dev.next is useless. It was probably cargo-culted from
  some driver while hoping to enumerate devices (not that uncommon the
  early 2000). PCI driver registeering could thus look more idiomatic.
- deinit_card can be called two times in an error path and trigger a BUG_ON
  in atm_dev_deregister.

-- 
Ueimor