Hi,
I have a module that copies things to userspace from a log using copy_to_user. I initially wrote the code using semaphores. However, the code is called from places where sleeping is not allowed so I am switching it to spinlocks. Before running into any issues with kmalloc returning NULL (because it now uses GFP_ATOMIC rather than GFP_KERNEL), copy_to_user automatically returns an error, when called under spinlock. I call spin_lock and spin_unlock (no interrupts are off) and have no clue what is causing this. Any advice? I feel like I need to pin pages in memory first or something, but shouldn't that not be a problem until much later?
Thank you very much for your help, Can Sar
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