On 8/7/20 3:16 AM, Xiaoming Ni wrote:
> Realpath() cyclically invokes __alloca() when processing soft link files,
> which may consume 164 KB stack space.
> Therefore, replace __alloca with malloc to reduce stack overflow risks

I don't understand why malloc is required here.

Isn't the problem that the buffer is being allocated over and over again? And if 
you fix that bug, the function should allocate only 8 KiB via __alloca on 
GNU/Linux. Something like the attached (untested) patch, say. So why not keep 
using the stack? That would be more efficient than resorting to the heap.