From: Al Viro <viro@ZenIV.linux.org.uk>
To: Thomas Meyer <thomas@m3y3r.de>
Cc: perex@perex.cz, tiwai@suse.com, alsa-devel@alsa-project.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/4] ALSA: emu10k1: Cocci spatch "alloc_cast"
Date: Thu, 21 Sep 2017 18:39:15 +0100 [thread overview]
Message-ID: <20170921173914.GK32076@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1505975570447-568224618-4-diffsplit-thomas@m3y3r.de>
On Thu, Sep 21, 2017 at 08:33:46AM +0200, Thomas Meyer wrote:
> Remove casting the values returned by memory allocation functions like
> kmalloc, kzalloc, kmem_cache_alloc, kmem_cache_zalloc etc."
> Found by coccinelle spatch "api/alloc/alloc_cast.cocci"
>
> Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
> ---
>
> diff -u -p a/sound/pci/emu10k1/emufx.c b/sound/pci/emu10k1/emufx.c
> --- a/sound/pci/emu10k1/emufx.c
> +++ b/sound/pci/emu10k1/emufx.c
> @@ -1218,7 +1218,7 @@ static int _snd_emu10k1_audigy_init_efx(
> if (!icode)
> return err;
>
> - icode->gpr_map = (u_int32_t __user *) kcalloc(512 + 256 + 256 + 2 * 1024,
> + icode->gpr_map = kcalloc(512 + 256 + 256 + 2 * 1024,
> sizeof(u_int32_t), GFP_KERNEL);
And _this_ is a wonderful example of the reasons why that kind of
patches is bloody bad. The code you've caught is very obviously smelly -
kcalloc() does *NOT* return a userland pointer. You are whitewashing it;
a major "something weird is going on here" sign is gone (something weird
in that case is hopefully a set_fs(KERNEL_DS) somewhere nearby, and it
is asking for careful review).
FWIW, any patches of that sort anywhere near VFS are very much not welcome.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Thomas Meyer <thomas@m3y3r.de>
Cc: linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org,
tiwai@suse.com
Subject: Re: [PATCH 4/4] ALSA: emu10k1: Cocci spatch "alloc_cast"
Date: Thu, 21 Sep 2017 18:39:15 +0100 [thread overview]
Message-ID: <20170921173914.GK32076@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1505975570447-568224618-4-diffsplit-thomas@m3y3r.de>
On Thu, Sep 21, 2017 at 08:33:46AM +0200, Thomas Meyer wrote:
> Remove casting the values returned by memory allocation functions like
> kmalloc, kzalloc, kmem_cache_alloc, kmem_cache_zalloc etc."
> Found by coccinelle spatch "api/alloc/alloc_cast.cocci"
>
> Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
> ---
>
> diff -u -p a/sound/pci/emu10k1/emufx.c b/sound/pci/emu10k1/emufx.c
> --- a/sound/pci/emu10k1/emufx.c
> +++ b/sound/pci/emu10k1/emufx.c
> @@ -1218,7 +1218,7 @@ static int _snd_emu10k1_audigy_init_efx(
> if (!icode)
> return err;
>
> - icode->gpr_map = (u_int32_t __user *) kcalloc(512 + 256 + 256 + 2 * 1024,
> + icode->gpr_map = kcalloc(512 + 256 + 256 + 2 * 1024,
> sizeof(u_int32_t), GFP_KERNEL);
And _this_ is a wonderful example of the reasons why that kind of
patches is bloody bad. The code you've caught is very obviously smelly -
kcalloc() does *NOT* return a userland pointer. You are whitewashing it;
a major "something weird is going on here" sign is gone (something weird
in that case is hopefully a set_fs(KERNEL_DS) somewhere nearby, and it
is asking for careful review).
FWIW, any patches of that sort anywhere near VFS are very much not welcome.
next prev parent reply other threads:[~2017-09-21 17:39 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-21 6:33 [PATCH 0/4] Cocci spatch "alloc_cast" - v4.14-rc1 Thomas Meyer
2017-09-21 6:33 ` [PATCH 4/4] ALSA: emu10k1: Cocci spatch "alloc_cast" Thomas Meyer
2017-09-21 8:00 ` Takashi Iwai
2017-09-21 8:00 ` Takashi Iwai
2017-09-21 17:39 ` Al Viro [this message]
2017-09-21 17:39 ` Al Viro
2017-09-21 20:39 ` Takashi Iwai
2017-09-21 20:39 ` Takashi Iwai
2017-09-21 6:33 ` [PATCH 3/4] VFS: normal filesystems (and lustre): " Thomas Meyer
2017-09-21 6:33 ` [PATCH 1/4] drm/amd/powerplay: " Thomas Meyer
2017-09-21 6:55 ` Deucher, Alexander
2017-09-26 16:10 ` Alex Deucher
2017-09-26 16:10 ` Alex Deucher
2017-09-21 6:33 ` [PATCH 2/4] fs: " Thomas Meyer
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