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From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Giulio Benetti <giulio.benetti@micronovasrl.com>
Cc: David Airlie <airlied@linux.ie>, Chen-Yu Tsai <wens@csie.org>,
	dri-devel@lists.freedesktop.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] drm/sun4i: tcon: fix check of tcon->panel null pointer
Date: Thu, 4 Oct 2018 21:54:06 +0200	[thread overview]
Message-ID: <20181004195406.prjuko556tnuau2u@flea> (raw)
In-Reply-To: <20181003142458.33120-1-giulio.benetti@micronovasrl.com>

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Hi,

On Wed, Oct 03, 2018 at 04:24:57PM +0200, Giulio Benetti wrote:
> At the moment, the check of tcon->panel to be valid is wrong. IS_ERR()
> has been used, but that macro doesn't check if tcon->panel pointer is
> null or not, but check if tcon->panel is between -1 and -4095(MAX_ERRNO).
> 
> Remove IS_ERR() from tcon->panel checking and let "if (tcon->panel)" as
> condition to check if it's a pointer not null.
> 
> Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com>

The commit log should be improved. The issue isn't really with the
IS_ERR macro as you suggest, but that what is returned by
of_drm_find_panel, and thus stored in tcon->panel. is not an error
pointer in the first place but a NULL pointer on error. So the check
doesn't check for the proper thing.

Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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      parent reply	other threads:[~2018-10-04 19:54 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20181001093612.GA13672@mwanda>
2018-10-02 20:48 ` [PATCH 1/2] drm/sun4i: tcon: fix check of tcon->panel null pointer Giulio Benetti
2018-10-02 20:49   ` [PATCH 2/2] drm/sun4i: tcon: prevent tcon->panel dereference if null Giulio Benetti
2018-10-02 21:59 ` [PATCH 1/2] drm/sun4i: tcon: fix check of tcon->panel null pointer Giulio Benetti
2018-10-02 21:59   ` [PATCH 2/2] drm/sun4i: tcon: prevent tcon->panel dereference if null Giulio Benetti
2018-10-03  7:34     ` Chen-Yu Tsai
2018-10-02 22:00   ` [PATCH 1/2] drm/sun4i: tcon: fix check of tcon->panel null pointer Giulio Benetti
2018-10-03  9:43   ` Chen-Yu Tsai
2018-10-03 12:13     ` Giulio Benetti
2018-10-03 14:24       ` [PATCH v2 " Giulio Benetti
2018-10-03 14:24         ` [PATCH v2 2/2] drm/sun4i: tcon: prevent tcon->panel dereference if null Giulio Benetti
2018-10-04 19:56           ` Maxime Ripard
2018-10-05 21:38             ` Giulio Benetti
2018-10-05 21:59             ` [PATCH v3 1/2] drm/sun4i: tcon: fix check of tcon->panel null pointer Giulio Benetti
2018-10-05 21:59               ` [PATCH v3 2/2] drm/sun4i: tcon: prevent tcon->panel dereference if NULL Giulio Benetti
2018-10-08  9:21                 ` Maxime Ripard
2018-10-12 10:03                   ` Chen-Yu Tsai
2018-11-05 13:23                   ` Icenowy Zheng
2018-11-06 15:57                     ` Maxime Ripard
2018-10-04 19:54         ` Maxime Ripard [this message]

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