CODEWITHSUNDEEP
memory-managementlinux-kerneldriver
Victor
Victor

Reputation: 48

Do built-in kernel drivers need kfree?

For a device driver that is compiled into the Linux kernel, should kmalloc'ed memory be freed with corresponding kfree() calls?

I am talking about memory that's allocated on initialization once and not something that is continuously allocated during the driver's lifespan. I assume that freeing the allocated memory is not necessary because the built-in driver lifespan is the lifespan of the kernel. Yes, the allocated memory is necessary for driver operation and cannot be freed after driver init; i.e. no __init macro possible.

I have not seen the above stated explicitly, and want to be sure.

Upvotes: 1

Views: 271

Answers (1)

0andriy
0andriy

Reputation: 4664

It depends. But very few modules (which are drivers) can't be compiled as such. Moreover it's a good programming style.

By the way, you may consider to use device managed resources, like memory allocated via devm_kzalloc. It will take care of the allocated resources on probe stage and allows you to clean up an error path there as well.

Upvotes: 3

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