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Message-ID: <0ce9cde4-de94-856b-329c-d75929799bb2@linaro.org>
Date: Fri, 10 Dec 2021 17:35:01 -0600
From: Alex Elder <elder@...aro.org>
To: Nathan Chancellor <nathan@...nel.org>,
Vaibhav Agarwal <vaibhav.sr@...il.com>,
Mark Greer <mgreer@...malcreek.com>,
Johan Hovold <johan@...nel.org>, Alex Elder <elder@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Arnd Bergmann <arnd@...db.de>
Cc: llvm@...ts.linux.dev, linux-staging@...ts.linux.dev,
Nick Desaulniers <ndesaulniers@...gle.com>,
linux-kernel@...r.kernel.org, greybus-dev@...ts.linaro.org
Subject: Re: [greybus-dev] [PATCH v2] staging: greybus: fix stack size warning
with UBSAN
On 12/9/21 1:51 PM, Nathan Chancellor wrote:
> From: Arnd Bergmann <arnd@...db.de>
>
> clang warns about excessive stack usage in this driver when
> UBSAN is enabled:
>
> drivers/staging/greybus/audio_topology.c:977:12: error: stack frame size of 1836 bytes in function 'gbaudio_tplg_create_widget' [-Werror,-Wframe-larger-than=]
>
> Rework this code to no longer use compound literals for
> initializing the structure in each case, but instead keep
> the common bits in a preallocated constant array and copy
> them as needed.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1535
> Link: https://lore.kernel.org/r/20210103223541.2790855-1-arnd@kernel.org/
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> [nathan: Address review comments from v1]
> Signed-off-by: Nathan Chancellor <nathan@...nel.org>
This looks good to me and it seems the switch statement
becomes much more concise.
One thing I would suggest is that you somehow capture
in comments the fact that you're manually assigning the
widget name and in a couple spots the "sname" (I don't know
what that represents).
Someday these SND_SOC_DAPM*() macros could be changed,
and it would be helpful to have a little guidance around
this code to explain what was done here.
This isn't critical, but would improve maintainability.
We can see what others think, but either way:
Reviewed-by: Alex Elder <elder@...aro.org>
> ---
>
> v1 -> v2: https://lore.kernel.org/r/20210103223541.2790855-1-arnd@kernel.org/
>
> * Use NULL for name field in SND_DOC_DAPM_* in gbaudio_widgets (Alex).
>
> * Do not eliminate *dw assignment within the switch cases, as invalid
> enum values in-between valid enum values (such as snd_soc_dapm_demux)
> would not be handled properly by the "if value is greater than the
> array size" check (Alex). This addresses a few other comments by Alex
> and Dan because w->type is not checked against the array's size.
>
> Arnd, if you disagree with this approach, please let me know so that we
> can get this fixed in a way that everyone is happy with.
>
> drivers/staging/greybus/audio_topology.c | 92 ++++++++++++------------
> 1 file changed, 45 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/staging/greybus/audio_topology.c b/drivers/staging/greybus/audio_topology.c
> index 1e613d42d823..7f7d558b76d0 100644
> --- a/drivers/staging/greybus/audio_topology.c
> +++ b/drivers/staging/greybus/audio_topology.c
> @@ -974,6 +974,44 @@ static int gbaudio_widget_event(struct snd_soc_dapm_widget *w,
> return ret;
> }
>
> +static const struct snd_soc_dapm_widget gbaudio_widgets[] = {
> + [snd_soc_dapm_spk] = SND_SOC_DAPM_SPK(NULL, gbcodec_event_spk),
> + [snd_soc_dapm_hp] = SND_SOC_DAPM_HP(NULL, gbcodec_event_hp),
> + [snd_soc_dapm_mic] = SND_SOC_DAPM_MIC(NULL, gbcodec_event_int_mic),
> + [snd_soc_dapm_output] = SND_SOC_DAPM_OUTPUT(NULL),
> + [snd_soc_dapm_input] = SND_SOC_DAPM_INPUT(NULL),
> + [snd_soc_dapm_switch] = SND_SOC_DAPM_SWITCH_E(NULL, SND_SOC_NOPM,
> + 0, 0, NULL,
> + gbaudio_widget_event,
> + SND_SOC_DAPM_PRE_PMU |
> + SND_SOC_DAPM_POST_PMD),
> + [snd_soc_dapm_pga] = SND_SOC_DAPM_PGA_E(NULL, SND_SOC_NOPM,
> + 0, 0, NULL, 0,
> + gbaudio_widget_event,
> + SND_SOC_DAPM_PRE_PMU |
> + SND_SOC_DAPM_POST_PMD),
> + [snd_soc_dapm_mixer] = SND_SOC_DAPM_MIXER_E(NULL, SND_SOC_NOPM,
> + 0, 0, NULL, 0,
> + gbaudio_widget_event,
> + SND_SOC_DAPM_PRE_PMU |
> + SND_SOC_DAPM_POST_PMD),
> + [snd_soc_dapm_mux] = SND_SOC_DAPM_MUX_E(NULL, SND_SOC_NOPM,
> + 0, 0, NULL,
> + gbaudio_widget_event,
> + SND_SOC_DAPM_PRE_PMU |
> + SND_SOC_DAPM_POST_PMD),
> + [snd_soc_dapm_aif_in] = SND_SOC_DAPM_AIF_IN_E(NULL, NULL, 0,
> + SND_SOC_NOPM, 0, 0,
> + gbaudio_widget_event,
> + SND_SOC_DAPM_PRE_PMU |
> + SND_SOC_DAPM_POST_PMD),
> + [snd_soc_dapm_aif_out] = SND_SOC_DAPM_AIF_OUT_E(NULL, NULL, 0,
> + SND_SOC_NOPM, 0, 0,
> + gbaudio_widget_event,
> + SND_SOC_DAPM_PRE_PMU |
> + SND_SOC_DAPM_POST_PMD),
> +};
> +
> static int gbaudio_tplg_create_widget(struct gbaudio_module_info *module,
> struct snd_soc_dapm_widget *dw,
> struct gb_audio_widget *w, int *w_size)
> @@ -1052,77 +1090,37 @@ static int gbaudio_tplg_create_widget(struct gbaudio_module_info *module,
>
> switch (w->type) {
> case snd_soc_dapm_spk:
> - *dw = (struct snd_soc_dapm_widget)
> - SND_SOC_DAPM_SPK(w->name, gbcodec_event_spk);
> + *dw = gbaudio_widgets[w->type];
> module->op_devices |= GBAUDIO_DEVICE_OUT_SPEAKER;
> break;
> case snd_soc_dapm_hp:
> - *dw = (struct snd_soc_dapm_widget)
> - SND_SOC_DAPM_HP(w->name, gbcodec_event_hp);
> + *dw = gbaudio_widgets[w->type];
> module->op_devices |= (GBAUDIO_DEVICE_OUT_WIRED_HEADSET
> | GBAUDIO_DEVICE_OUT_WIRED_HEADPHONE);
> module->ip_devices |= GBAUDIO_DEVICE_IN_WIRED_HEADSET;
> break;
> case snd_soc_dapm_mic:
> - *dw = (struct snd_soc_dapm_widget)
> - SND_SOC_DAPM_MIC(w->name, gbcodec_event_int_mic);
> + *dw = gbaudio_widgets[w->type];
> module->ip_devices |= GBAUDIO_DEVICE_IN_BUILTIN_MIC;
> break;
> case snd_soc_dapm_output:
> - *dw = (struct snd_soc_dapm_widget)SND_SOC_DAPM_OUTPUT(w->name);
> - break;
> case snd_soc_dapm_input:
> - *dw = (struct snd_soc_dapm_widget)SND_SOC_DAPM_INPUT(w->name);
> - break;
> case snd_soc_dapm_switch:
> - *dw = (struct snd_soc_dapm_widget)
> - SND_SOC_DAPM_SWITCH_E(w->name, SND_SOC_NOPM, 0, 0,
> - widget_kctls,
> - gbaudio_widget_event,
> - SND_SOC_DAPM_PRE_PMU |
> - SND_SOC_DAPM_POST_PMD);
> - break;
> case snd_soc_dapm_pga:
> - *dw = (struct snd_soc_dapm_widget)
> - SND_SOC_DAPM_PGA_E(w->name, SND_SOC_NOPM, 0, 0, NULL, 0,
> - gbaudio_widget_event,
> - SND_SOC_DAPM_PRE_PMU |
> - SND_SOC_DAPM_POST_PMD);
> - break;
> case snd_soc_dapm_mixer:
> - *dw = (struct snd_soc_dapm_widget)
> - SND_SOC_DAPM_MIXER_E(w->name, SND_SOC_NOPM, 0, 0, NULL,
> - 0, gbaudio_widget_event,
> - SND_SOC_DAPM_PRE_PMU |
> - SND_SOC_DAPM_POST_PMD);
> - break;
> case snd_soc_dapm_mux:
> - *dw = (struct snd_soc_dapm_widget)
> - SND_SOC_DAPM_MUX_E(w->name, SND_SOC_NOPM, 0, 0,
> - widget_kctls, gbaudio_widget_event,
> - SND_SOC_DAPM_PRE_PMU |
> - SND_SOC_DAPM_POST_PMD);
> + *dw = gbaudio_widgets[w->type];
> break;
> case snd_soc_dapm_aif_in:
> - *dw = (struct snd_soc_dapm_widget)
> - SND_SOC_DAPM_AIF_IN_E(w->name, w->sname, 0,
> - SND_SOC_NOPM,
> - 0, 0, gbaudio_widget_event,
> - SND_SOC_DAPM_PRE_PMU |
> - SND_SOC_DAPM_POST_PMD);
> - break;
> case snd_soc_dapm_aif_out:
> - *dw = (struct snd_soc_dapm_widget)
> - SND_SOC_DAPM_AIF_OUT_E(w->name, w->sname, 0,
> - SND_SOC_NOPM,
> - 0, 0, gbaudio_widget_event,
> - SND_SOC_DAPM_PRE_PMU |
> - SND_SOC_DAPM_POST_PMD);
> + *dw = gbaudio_widgets[w->type];
> + dw->sname = w->sname;
> break;
> default:
> ret = -EINVAL;
> goto error;
> }
> + dw->name = w->name;
>
> dev_dbg(module->dev, "%s: widget of type %d created\n", dw->name,
> dw->id);
>
> base-commit: 42eb8fdac2fc5d62392dcfcf0253753e821a97b0
>
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