eCryptfs

Why is the kernel stack such an issue with eCryptfs?

Asked by Dustin Kirkland 

eCryptfs is a stacked filesystem. This implies that eCryptfs adds on top of whatever call stack exists with current filesystems. Each process in the Linux kernel has a fixed maximum stack size (4k+4k or 8k). Some filesystems (such as XFS) push the limit of the stack by themselves; adding eCryptfs on top may cause a stack overflow on these filesystems. If you wish to use eCryptfs on XFS, I recommend that you first perform stress tests to help determine whether your specific configuration will lead to a kernel process stack overflow.

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Dustin Kirkland 
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Dustin Kirkland  (kirkland) said : 		#1

From the FAQ:

eCryptfs is a stacked filesystem. This implies that eCryptfs adds on top of whatever call stack exists with current filesystems. Each process in the Linux kernel has a fixed maximum stack size (4k+4k or 8k). Some filesystems (such as XFS) push the limit of the stack by themselves; adding eCryptfs on top may cause a stack overflow on these filesystems. If you wish to use eCryptfs on XFS, I recommend that you first perform stress tests to help determine whether your specific configuration will lead to a kernel process stack overflow.