From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mika Westerberg <westeri@kernel.org>,
linux-gpio@vger.kernel.org, linux-acpi@vger.kernel.org,
linux-kernel@vger.kernel.org, Linus Walleij <linusw@kernel.org>,
Bartosz Golaszewski <brgl@kernel.org>
Subject: Re: [PATCH v2 1/1] gpiolib: acpi: Fix potential out-of-boundary left shift
Date: Tue, 27 Jan 2026 14:43:00 +0100 [thread overview]
Message-ID: <20260127134300.GK2275908@black.igk.intel.com> (raw)
In-Reply-To: <20260127110824.4020130-1-andriy.shevchenko@linux.intel.com>
On Tue, Jan 27, 2026 at 12:06:30PM +0100, Andy Shevchenko wrote:
> GPIO Address Space handler gets a pointer to the in or out value.
> This value is supposed to be at least 64-bit, but it's not limited
> to be exactly 64-bit. When ACPI tables are being parsed, for
> the bigger Connection():s ACPICA creates a Buffer instead of regular
> Integer object. The Buffer exists as long as Namespace holds
> the certain Connection(). Hence we can access the necessary bits
> without worrying. On the other hand, the left shift, used in
> the code, is limited by 31 (on 32-bit platforms) and otherwise
> considered to be Undefined Behaviour. Also the code uses only
> the first 64-bit word for the value, and anything bigger than 63
> will be also subject to UB. Fix all this by modifying the code
> to correctly set or clear the respective bit in the bitmap constructed
> of 64-bit words.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Perfect, thanks!
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
next prev parent reply other threads:[~2026-01-27 13:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-27 11:06 Andy Shevchenko
2026-01-27 13:43 ` Mika Westerberg [this message]
2026-01-27 13:49 ` Andy Shevchenko
2026-01-28 9:02 ` Bartosz Golaszewski
2026-01-28 9:10 ` Andy Shevchenko
2026-01-28 9:00 ` Bartosz Golaszewski
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