Re: [RFC PATCH] coccinelle: misc: add uninitialized_var.cocci script

[Julia Lawall]

On Wed, 12 Aug 2020, Denis Efremov wrote:

> Commit 63a0895d960a ("compiler: Remove uninitialized_var() macro") and
> commit 4b19bec97c88 ("docs: deprecated.rst: Add uninitialized_var()")
> removed uninitialized_var() and deprecated it.
>
> The purpose of this script is to prevent new occurrences of open-coded
> variants of uninitialized_var().
>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
> Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>

Applied, without the commented out part.

I only got three warnings, though.  Perhaps the others have been fixed?

lib/glob.c:48:31-39: WARNING: this kind of initialization is deprecated
drivers/gpu/drm/nouveau/nvkm/subdev/instmem/nv50.c:316:7-10: WARNING: this kind of initialization is deprecated
tools/testing/selftests/vm/userfaultfd.c:349:15-22: WARNING: this kind of initialization is deprecated

julia

> ---
> List of warnings:
> ./lib/glob.c:48:31-39: WARNING: this kind of initialization is deprecated
> ./tools/testing/selftests/vm/userfaultfd.c:349:15-22: WARNING: this kind of initialization is deprecated
> ./drivers/block/drbd/drbd_vli.h:330:5-9: WARNING: this kind of initialization is deprecated
> ./drivers/char/hw_random/intel-rng.c:333:15-18: WARNING: this kind of initialization is deprecated
> ./drivers/gpu/drm/nouveau/nvkm/subdev/instmem/nv50.c:316:7-10: WARNING: this kind of initialization is deprecated
> ./arch/x86/include/asm/paravirt_types.h:455:15-20: WARNING: this kind of initialization is deprecated
> ./arch/x86/include/asm/paravirt_types.h:455:30-35: WARNING: this kind of initialization is deprecated
> ./arch/x86/include/asm/paravirt_types.h:455:45-50: WARNING: this kind of initialization is deprecated
> ./arch/x86/include/asm/paravirt_types.h:475:15-20: WARNING: this kind of initialization is deprecated
> ./arch/x86/include/asm/paravirt_types.h:475:30-35: WARNING: this kind of initialization is deprecated
> ./arch/x86/include/asm/paravirt_types.h:476:2-7: WARNING: this kind of initialization isdeprecated
> ./arch/x86/include/asm/paravirt_types.h:476:17-22: WARNING: this kind of initialization is deprecated
> ./arch/x86/include/asm/paravirt_types.h:476:32-37: WARNING: this kind of initialization is deprecated
>
>  .../coccinelle/misc/uninitialized_var.cocci   | 51 +++++++++++++++++++
>  1 file changed, 51 insertions(+)
>  create mode 100644 scripts/coccinelle/misc/uninitialized_var.cocci
>
> diff --git a/scripts/coccinelle/misc/uninitialized_var.cocci b/scripts/coccinelle/misc/uninitialized_var.cocci
> new file mode 100644
> index 000000000000..e4787bc6ab9c
> --- /dev/null
> +++ b/scripts/coccinelle/misc/uninitialized_var.cocci
> @@ -0,0 +1,51 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +///
> +/// uninitialized_var() and its open-coded variations are
> +/// deprecated. For details, see:
> +/// Documentation/process/deprecated.rst
> +///
> +// Confidence: High
> +// Copyright: (C) 2020 Denis Efremov ISPRAS
> +// Options: --no-includes --include-headers
> +//
> +
> +virtual context
> +virtual report
> +virtual org
> +
> +@r@
> +identifier var;
> +type T;
> +position p;
> +@@
> +
> +(
> +* T var@p = var;
> +|
> +* T var@p = *(&(var));
> +//|
> +// TODO: Actually, I'm not sure about this pattern.
> +// Looks like it's used in wireless drivers to determine
> +// whether data belongs to the driver or not.
> +// Here are all matches:
> +// https://elixir.bootlin.com/linux/latest/source/net/mac802154/util.c#L14
> +// https://elixir.bootlin.com/linux/latest/source/drivers/staging/wlan-ng/cfg80211.c#L48
> +// https://elixir.bootlin.com/linux/latest/source/drivers/net/wireless/intersil/orinoco/cfg.c#L21
> +// https://elixir.bootlin.com/linux/latest/source/net/mac80211/util.c#L37
> +// https://elixir.bootlin.com/linux/latest/source/drivers/net/wireless/rndis_wlan.c#L544
> +// * T *var@p = &var;
> +)
> +
> +@script:python depends on report@
> +p << r.p;
> +@@
> +
> +coccilib.report.print_report(p[0],
> +  "WARNING: this kind of initialization is deprecated")
> +
> +@script:python depends on org@
> +p << r.p;
> +@@
> +
> +coccilib.org.print_todo(p[0],
> +  "WARNING: this kind of initialization is deprecated")
> --
> 2.26.2
>
>