[Coverity CID :219649] Operands don't affect result in kernel/sem.c

[zephyrbot]

Static code scan issues found in file:

https://github.com/zephyrproject-rtos/zephyr/tree/bd97359a5338b2542d19011b6d6aa1d8d1b9cc3f/kernel/sem.c#L68

Category: Integer handling issues
Function: z_impl_k_sem_init
Component: Kernel
CID: 219649

Details:

zephyr/kernel/sem.c

Line 68 in bd97359

CHECKIF(limit == 0U || initial_count > limit) {

62     int z_impl_k_sem_init(struct k_sem *sem, unsigned int initial_count,
63                   unsigned int limit)
64     {
65         /*
66          * Limit cannot be zero and count cannot be greater than limit
67          */
>>>     CID 219649:  Integer handling issues  (CONSTANT_EXPRESSION_RESULT)
>>>     "limit > 4294967295U /* 2147483647 * 2U + 1U */" is always false regardless of the values of its operands. This occurs as the logical second operand of "||".
68         CHECKIF(limit == 0U || limit > K_SEM_MAX_LIMIT || initial_count > limit) {
69             return -EINVAL;
70         }
71    
72         sem->count = initial_count;
73         sem->limit = limit;

Please fix or provide comments in coverity using the link:

https://scan9.coverity.com/reports.htm#v32951/p12996.

Note: This issue was created automatically. Priority was set based on classification
of the file affected and the impact field in coverity. Assignees were set using the CODEOWNERS file.

[dcpleung]

@jharris-intel is limit > K_SEM_MAX_LIMIT needed in this case? I see K_SEM_MAX_LIMIT is #define to be UINT_MAX.

[jharris-intel]

What's the recommended approach when a limiting constant could be UINT_MAX in some, but not all, configurations?

That constant was added because I've got a WIP PR that adds an implementation whose limit is INT_MAX.

[dcpleung]

I assume we can ignore it as intentional in Coverity? @ceolin what do you think?

[ceolin]

I assume we can ignore it as intentional in Coverity? @ceolin what do you think?

Yep, we have others similar cases. This just need to be triaged as intentional

[dcpleung]

Done.