From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Ranjan Kumar <kumarranja@chromium.org>
Cc: bleung@chromium.org, dusonlin@emc.com.tw, bentiss@kernel.org,
linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Input: elan_i2c - prevent division by zero on invalid device parameters
Date: Wed, 13 May 2026 14:00:33 -0700 [thread overview]
Message-ID: <agTlxHSZqSI8cnjK@google.com> (raw)
In-Reply-To: <20260513073908.3326178-1-kumarranja@chromium.org>
Hi Ranjan,
On Wed, May 13, 2026 at 07:39:08AM +0000, Ranjan Kumar wrote:
> The Elan I2C touchpad driver queries the device for its physical
> dimensions and trace counts to calculate the device resolution and width.
> However, if the device firmware or device tree provides invalid zero
> values for x_traces, y_traces, x_mm, or y_mm, it results in a fatal
> division-by-zero exception leading to a kernel panic during device probe.
>
Neither crashing nor aborting probe with -EINVAL is great as we will not
be able to flash another firmware.
How do we get into this state? Is this something actually observed or
just theoretical?
> Add sanity checks to ensure these physical parameters are non-zero
> before performing the division. If invalid values are detected, log an
> error and return -EINVAL to gracefully abort the initialization and
> maintain system stability.
That is hardly "stability" for a laptop when its pointer is not working.
Thanks.
--
Dmitry
next prev parent reply other threads:[~2026-05-13 21:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-13 7:39 [PATCH] Input: elan_i2c - prevent division by zero on invalid device parameters Ranjan Kumar
2026-05-13 21:00 ` Dmitry Torokhov [this message]
2026-05-15 6:52 ` [PATCH v2] " Ranjan Kumar
2026-05-15 7:10 ` sashiko-bot
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