* [PATCH] drm/amd/powerplay: ensure loop does not wraparound on decrement
@ 2017-05-17 18:13 ` Colin King
0 siblings, 0 replies; 8+ messages in thread
From: Colin King @ 2017-05-17 18:13 UTC (permalink / raw)
To: Alex Deucher, Christian König, David Airlie, Rex Zhu,
Eric Huang, Huang Rui, amd-gfx, dri-devel
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
The current for loop decrements i when it is zero and this causes
a wrap-around back to ~0 because i is unsigned. In the unlikely event
that mask is 0, the loop will run forever. Fix this so we can't loop
forever.
Detected by CoverityScan, CID#1435469 ("Unsigned compared against 0")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
index ad30f5d3a10d..d92c9b9b15be 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
@@ -4199,7 +4199,7 @@ static int vega10_force_clock_level(struct pp_hwmgr *hwmgr,
}
data->smc_state_table.gfx_boot_level = i;
- for (i = 31; i >= 0; i--) {
+ for (i = 32; --i; ) {
if (mask & (1 << i))
break;
}
--
2.11.0
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH] drm/amd/powerplay: ensure loop does not wraparound on decrement
@ 2017-05-17 18:13 ` Colin King
0 siblings, 0 replies; 8+ messages in thread
From: Colin King @ 2017-05-17 18:13 UTC (permalink / raw)
To: Alex Deucher, Christian König, David Airlie, Rex Zhu,
Eric Huang, Huang Rui, amd-gfx, dri-devel
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
The current for loop decrements i when it is zero and this causes
a wrap-around back to ~0 because i is unsigned. In the unlikely event
that mask is 0, the loop will run forever. Fix this so we can't loop
forever.
Detected by CoverityScan, CID#1435469 ("Unsigned compared against 0")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
index ad30f5d3a10d..d92c9b9b15be 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
@@ -4199,7 +4199,7 @@ static int vega10_force_clock_level(struct pp_hwmgr *hwmgr,
}
data->smc_state_table.gfx_boot_level = i;
- for (i = 31; i >= 0; i--) {
+ for (i = 32; --i; ) {
if (mask & (1 << i))
break;
}
--
2.11.0
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH] drm/amd/powerplay: ensure loop does not wraparound on decrement
2017-05-17 18:13 ` Colin King
(?)
@ 2017-05-17 19:30 ` Dan Carpenter
-1 siblings, 0 replies; 8+ messages in thread
From: Dan Carpenter @ 2017-05-17 19:30 UTC (permalink / raw)
To: Colin King
Cc: kernel-janitors, linux-kernel, amd-gfx, Eric Huang, Huang Rui,
dri-devel, Alex Deucher, Rex Zhu, Christian König
I sent a patch for this bug earlier. There is a second bug later in the
function which my patch fixes as well.
regards,
dan carpenter
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/amd/powerplay: ensure loop does not wraparound on decrement
@ 2017-05-17 19:30 ` Dan Carpenter
0 siblings, 0 replies; 8+ messages in thread
From: Dan Carpenter @ 2017-05-17 19:30 UTC (permalink / raw)
To: Colin King
Cc: Alex Deucher, Christian König, David Airlie, Rex Zhu,
Eric Huang, Huang Rui, amd-gfx, dri-devel, kernel-janitors,
linux-kernel
I sent a patch for this bug earlier. There is a second bug later in the
function which my patch fixes as well.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/amd/powerplay: ensure loop does not wraparound on decrement
@ 2017-05-17 19:30 ` Dan Carpenter
0 siblings, 0 replies; 8+ messages in thread
From: Dan Carpenter @ 2017-05-17 19:30 UTC (permalink / raw)
To: Colin King
Cc: kernel-janitors, linux-kernel, amd-gfx, Eric Huang, Huang Rui,
dri-devel, Alex Deucher, Rex Zhu, Christian König
I sent a patch for this bug earlier. There is a second bug later in the
function which my patch fixes as well.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] drm/amd/powerplay: ensure loop does not wraparound on decrement
2017-05-17 18:13 ` Colin King
@ 2017-05-18 7:15 ` walter harms
-1 siblings, 0 replies; 8+ messages in thread
From: walter harms @ 2017-05-18 7:15 UTC (permalink / raw)
To: Colin King
Cc: Alex Deucher, Christian König, David Airlie, Rex Zhu,
Eric Huang, Huang Rui, amd-gfx, dri-devel, kernel-janitors,
linux-kernel
Am 17.05.2017 20:13, schrieb Colin King:
> From: Colin Ian King <colin.king@canonical.com>
>
> The current for loop decrements i when it is zero and this causes
> a wrap-around back to ~0 because i is unsigned. In the unlikely event
> that mask is 0, the loop will run forever. Fix this so we can't loop
> forever.
>
> Detected by CoverityScan, CID#1435469 ("Unsigned compared against 0")
>
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
> index ad30f5d3a10d..d92c9b9b15be 100644
> --- a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
> +++ b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
> @@ -4199,7 +4199,7 @@ static int vega10_force_clock_level(struct pp_hwmgr *hwmgr,
> }
> data->smc_state_table.gfx_boot_level = i;
>
> - for (i = 31; i >= 0; i--) {
> + for (i = 32; --i; ) {
> if (mask & (1 << i))
> break;
> }
nitpicking:
we notices at several points that programmers are bad at counting backwards.
Is there a reason not to start with i=0 ?
re,
wh
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] drm/amd/powerplay: ensure loop does not wraparound on decrement
@ 2017-05-18 7:15 ` walter harms
0 siblings, 0 replies; 8+ messages in thread
From: walter harms @ 2017-05-18 7:15 UTC (permalink / raw)
To: Colin King
Cc: Alex Deucher, Christian König, David Airlie, Rex Zhu,
Eric Huang, Huang Rui, amd-gfx, dri-devel, kernel-janitors,
linux-kernel
Am 17.05.2017 20:13, schrieb Colin King:
> From: Colin Ian King <colin.king@canonical.com>
>
> The current for loop decrements i when it is zero and this causes
> a wrap-around back to ~0 because i is unsigned. In the unlikely event
> that mask is 0, the loop will run forever. Fix this so we can't loop
> forever.
>
> Detected by CoverityScan, CID#1435469 ("Unsigned compared against 0")
>
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
> index ad30f5d3a10d..d92c9b9b15be 100644
> --- a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
> +++ b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
> @@ -4199,7 +4199,7 @@ static int vega10_force_clock_level(struct pp_hwmgr *hwmgr,
> }
> data->smc_state_table.gfx_boot_level = i;
>
> - for (i = 31; i >= 0; i--) {
> + for (i = 32; --i; ) {
> if (mask & (1 << i))
> break;
> }
nitpicking:
we notices at several points that programmers are bad at counting backwards.
Is there a reason not to start with i=0 ?
re,
wh
^ permalink raw reply [flat|nested] 8+ messages in thread