* [PATCH] tools thermal tmon: Fix signed shift UB in binding display
@ 2026-09-03 8:28 liujing
2026-09-28 16:39 ` Daniel Lezcano
0 siblings, 1 reply; 2+ messages in thread
From: liujing @ 2026-09-03 8:28 UTC (permalink / raw)
To: Rafael J . Wysocki, Daniel Lezcano
Cc: Zhang Rui, Lukasz Luba, linux-pm, linux-kernel, Liu Jing
From: Liu Jing <liujing@cmss.chinamobile.com>
In the thermal zone binding display loop, the expression `(1 << j)`
performs a signed integer shift. When j reaches 31, this sets the
sign bit of a 32-bit signed integer, which is undefined behavior.
Fix it by using `(1U << j)` to perform an unsigned shift.
Signed-off-by: Liu Jing <liujing@cmss.chinamobile.com>
---
--- a/tools/thermal/tmon/tmon.c
+++ b/tools/thermal/tmon/tmon.c
@@ -171,7 +171,7 @@
memset(binding_str, 0, sizeof(binding_str));
for (j = 0; j < 32; j++)
- binding_str[j] = (ptdata.tzi[i].cdev_binding & (1 << j)) ?
+ binding_str[j] = (ptdata.tzi[i].cdev_binding & (1U << j)) ?
'1' : '0';
fprintf(tmon_log, "#thermal zone %s%02d cdevs binding: %32s\n",
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] tools thermal tmon: Fix signed shift UB in binding display
2026-09-03 8:28 [PATCH] tools thermal tmon: Fix signed shift UB in binding display liujing
@ 2026-09-28 16:39 ` Daniel Lezcano
0 siblings, 0 replies; 2+ messages in thread
From: Daniel Lezcano @ 2026-09-28 16:39 UTC (permalink / raw)
To: liujing, Rafael J . Wysocki, Daniel Lezcano
Cc: Zhang Rui, Lukasz Luba, linux-pm, linux-kernel
On 9/3/26 10:28, liujing wrote:
> From: Liu Jing <liujing@cmss.chinamobile.com>
>
> In the thermal zone binding display loop, the expression `(1 << j)`
> performs a signed integer shift. When j reaches 31, this sets the
> sign bit of a 32-bit signed integer, which is undefined behavior.
>
> Fix it by using `(1U << j)` to perform an unsigned shift.
>
> Signed-off-by: Liu Jing <liujing@cmss.chinamobile.com>
> ---
Applied, thanks
^ permalink raw reply [flat|nested] 2+ messages in thread
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2026-09-03 8:28 [PATCH] tools thermal tmon: Fix signed shift UB in binding display liujing
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