[bug report] bpf: Implement dynptr copy kfuncs

[Dan Carpenter <dan.carpenter@linaro.org>]

Hello Mykyta Yatsenko,

Commit a498ee7576de ("bpf: Implement dynptr copy kfuncs") from May
12, 2025 (linux-next), leads to the following Smatch static checker
warning:

	kernel/trace/bpf_trace.c:3557 copy_user_data_sleepable()
	warn: maybe return -EFAULT instead of the bytes remaining?

kernel/trace/bpf_trace.c
    3551 static __always_inline int copy_user_data_sleepable(void *dst, const void *unsafe_src,
    3552                                                     u32 size, struct task_struct *tsk)
    3553 {
    3554         int ret;
    3555 
    3556         if (!tsk) /* Read from the current task */
--> 3557                 return copy_from_user(dst, (const void __user *)unsafe_src, size);

I don't know if it matters what we return here so long as it's non-zero.
This is probably a fast path so maybe we're returning positives
intentionally?

    3558 
    3559         ret = access_process_vm(tsk, (unsigned long)unsafe_src, dst, size, 0);
    3560         if (ret != size)
    3561                 return -EFAULT;
    3562         return 0;
    3563 }

regards,
dan carpenter