* [PATCH] drm/i915/gvt: Fix superfluous newline in GVT_DISPLAY_READY env var
@ 2017-02-20 13:58 Takashi Iwai
2017-02-20 14:52 ` ✓ Fi.CI.BAT: success for " Patchwork
2017-02-21 2:49 ` [PATCH] " Zhenyu Wang
0 siblings, 2 replies; 3+ messages in thread
From: Takashi Iwai @ 2017-02-20 13:58 UTC (permalink / raw)
To: intel-gvt-dev; +Cc: Richard Biener, intel-gfx, Daniel Vetter
send_display_send_uevent() sends two environment variable, and the
first one GVT_DISPLAY_READY is set including a new line at the end of
the string; that is obviously superfluous and wrong -- at least, it
*looks* so when you only read the code.
However, it doesn't appear in the actual output by a (supposedly
unexpected) trick. The code uses snprintf() and truncates the string
in size 20 bytes. This makes the string as GVT_DISPLAY_READY=0 or
...=1 including the trailing NUL-letter. That is, the '\n' found in
the format string is always cut off as a result.
Although the code gives the correct result, it is confusing. This
patch addresses it, just removing the superfluous '\n' from the format
string for avoiding further confusion. If the argument "ready" were
not a bool, the size 20 should be corrected as well. But it's a
bool, so we can leave the magic number 20 as is for now.
FWIW, the bug was spotted by a new GCC7 warning:
drivers/gpu/drm/i915/gvt/handlers.c: In function 'pvinfo_mmio_write':
drivers/gpu/drm/i915/gvt/handlers.c:1042:34: error: 'snprintf' output truncated before the last format character [-Werror=format-truncation=]
snprintf(display_ready_str, 20, "GVT_DISPLAY_READY=%d\n", ready);
^~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/i915/gvt/handlers.c:1042:2: note: 'snprintf' output 21 bytes into a destination of size 20
snprintf(display_ready_str, 20, "GVT_DISPLAY_READY=%d\n", ready);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fixes: 04d348ae3f0a ("drm/i915/gvt: vGPU display virtualization")
Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1025903
Reported-by: Richard Biener <rguenther@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/i915/gvt/handlers.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
index 1d450627ff65..845aa1511cbf 100644
--- a/drivers/gpu/drm/i915/gvt/handlers.c
+++ b/drivers/gpu/drm/i915/gvt/handlers.c
@@ -1039,7 +1039,7 @@ static int send_display_ready_uevent(struct intel_vgpu *vgpu, int ready)
char vmid_str[20];
char display_ready_str[20];
- snprintf(display_ready_str, 20, "GVT_DISPLAY_READY=%d\n", ready);
+ snprintf(display_ready_str, 20, "GVT_DISPLAY_READY=%d", ready);
env[0] = display_ready_str;
snprintf(vmid_str, 20, "VMID=%d", vgpu->id);
--
2.11.1
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* ✓ Fi.CI.BAT: success for drm/i915/gvt: Fix superfluous newline in GVT_DISPLAY_READY env var
2017-02-20 13:58 [PATCH] drm/i915/gvt: Fix superfluous newline in GVT_DISPLAY_READY env var Takashi Iwai
@ 2017-02-20 14:52 ` Patchwork
2017-02-21 2:49 ` [PATCH] " Zhenyu Wang
1 sibling, 0 replies; 3+ messages in thread
From: Patchwork @ 2017-02-20 14:52 UTC (permalink / raw)
To: Takashi Iwai; +Cc: intel-gfx
== Series Details ==
Series: drm/i915/gvt: Fix superfluous newline in GVT_DISPLAY_READY env var
URL : https://patchwork.freedesktop.org/series/19952/
State : success
== Summary ==
Series 19952v1 drm/i915/gvt: Fix superfluous newline in GVT_DISPLAY_READY env var
https://patchwork.freedesktop.org/api/1.0/series/19952/revisions/1/mbox/
fi-bdw-5557u total:252 pass:241 dwarn:0 dfail:0 fail:0 skip:11
fi-bsw-n3050 total:252 pass:213 dwarn:0 dfail:0 fail:0 skip:39
fi-bxt-j4205 total:252 pass:233 dwarn:0 dfail:0 fail:0 skip:19
fi-bxt-t5700 total:83 pass:70 dwarn:0 dfail:0 fail:0 skip:12
fi-byt-j1900 total:252 pass:225 dwarn:0 dfail:0 fail:0 skip:27
fi-byt-n2820 total:252 pass:221 dwarn:0 dfail:0 fail:0 skip:31
fi-hsw-4770 total:252 pass:236 dwarn:0 dfail:0 fail:0 skip:16
fi-hsw-4770r total:252 pass:236 dwarn:0 dfail:0 fail:0 skip:16
fi-ilk-650 total:252 pass:202 dwarn:0 dfail:0 fail:0 skip:50
fi-ivb-3520m total:252 pass:234 dwarn:0 dfail:0 fail:0 skip:18
fi-ivb-3770 total:252 pass:234 dwarn:0 dfail:0 fail:0 skip:18
fi-kbl-7500u total:252 pass:234 dwarn:0 dfail:0 fail:0 skip:18
fi-skl-6260u total:252 pass:242 dwarn:0 dfail:0 fail:0 skip:10
fi-skl-6700hq total:252 pass:235 dwarn:0 dfail:0 fail:0 skip:17
fi-skl-6700k total:252 pass:230 dwarn:4 dfail:0 fail:0 skip:18
fi-skl-6770hq total:252 pass:242 dwarn:0 dfail:0 fail:0 skip:10
fi-snb-2520m total:252 pass:224 dwarn:0 dfail:0 fail:0 skip:28
fi-snb-2600 total:252 pass:223 dwarn:0 dfail:0 fail:0 skip:29
45a2990174f3cf4dfa5d07b204d17b11d6a7410a drm-tip: 2017y-02m-20d-12h-54m-53s UTC integration manifest
5435d46 drm/i915/gvt: Fix superfluous newline in GVT_DISPLAY_READY env var
== Logs ==
For more details see: https://intel-gfx-ci.01.org/CI/Patchwork_3900/
_______________________________________________
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Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/i915/gvt: Fix superfluous newline in GVT_DISPLAY_READY env var
2017-02-20 13:58 [PATCH] drm/i915/gvt: Fix superfluous newline in GVT_DISPLAY_READY env var Takashi Iwai
2017-02-20 14:52 ` ✓ Fi.CI.BAT: success for " Patchwork
@ 2017-02-21 2:49 ` Zhenyu Wang
1 sibling, 0 replies; 3+ messages in thread
From: Zhenyu Wang @ 2017-02-21 2:49 UTC (permalink / raw)
To: Takashi Iwai; +Cc: Richard Biener, intel-gfx, Daniel Vetter, intel-gvt-dev
[-- Attachment #1.1: Type: text/plain, Size: 2988 bytes --]
On 2017.02.20 14:58:25 +0100, Takashi Iwai wrote:
> send_display_send_uevent() sends two environment variable, and the
> first one GVT_DISPLAY_READY is set including a new line at the end of
> the string; that is obviously superfluous and wrong -- at least, it
> *looks* so when you only read the code.
>
> However, it doesn't appear in the actual output by a (supposedly
> unexpected) trick. The code uses snprintf() and truncates the string
> in size 20 bytes. This makes the string as GVT_DISPLAY_READY=0 or
> ...=1 including the trailing NUL-letter. That is, the '\n' found in
> the format string is always cut off as a result.
>
> Although the code gives the correct result, it is confusing. This
> patch addresses it, just removing the superfluous '\n' from the format
> string for avoiding further confusion. If the argument "ready" were
> not a bool, the size 20 should be corrected as well. But it's a
> bool, so we can leave the magic number 20 as is for now.
>
> FWIW, the bug was spotted by a new GCC7 warning:
> drivers/gpu/drm/i915/gvt/handlers.c: In function 'pvinfo_mmio_write':
> drivers/gpu/drm/i915/gvt/handlers.c:1042:34: error: 'snprintf' output truncated before the last format character [-Werror=format-truncation=]
> snprintf(display_ready_str, 20, "GVT_DISPLAY_READY=%d\n", ready);
> ^~~~~~~~~~~~~~~~~~~~~~~~
> drivers/gpu/drm/i915/gvt/handlers.c:1042:2: note: 'snprintf' output 21 bytes into a destination of size 20
> snprintf(display_ready_str, 20, "GVT_DISPLAY_READY=%d\n", ready);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Fixes: 04d348ae3f0a ("drm/i915/gvt: vGPU display virtualization")
> Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1025903
> Reported-by: Richard Biener <rguenther@suse.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> ---
Applied. Thanks!
> drivers/gpu/drm/i915/gvt/handlers.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
> index 1d450627ff65..845aa1511cbf 100644
> --- a/drivers/gpu/drm/i915/gvt/handlers.c
> +++ b/drivers/gpu/drm/i915/gvt/handlers.c
> @@ -1039,7 +1039,7 @@ static int send_display_ready_uevent(struct intel_vgpu *vgpu, int ready)
> char vmid_str[20];
> char display_ready_str[20];
>
> - snprintf(display_ready_str, 20, "GVT_DISPLAY_READY=%d\n", ready);
> + snprintf(display_ready_str, 20, "GVT_DISPLAY_READY=%d", ready);
> env[0] = display_ready_str;
>
> snprintf(vmid_str, 20, "VMID=%d", vgpu->id);
> --
> 2.11.1
>
> _______________________________________________
> intel-gvt-dev mailing list
> intel-gvt-dev@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev
--
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2017-02-20 13:58 [PATCH] drm/i915/gvt: Fix superfluous newline in GVT_DISPLAY_READY env var Takashi Iwai
2017-02-20 14:52 ` ✓ Fi.CI.BAT: success for " Patchwork
2017-02-21 2:49 ` [PATCH] " Zhenyu Wang
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