Op 14-12-12 15:11, Rob Clark schreef:
On Fri, Dec 14, 2012 at 5:57 AM, Maarten Lankhorst m.b.lankhorst@gmail.com wrote:
Op 14-12-12 10:36, sumit.semwal@ti.com schreef:
From: Sumit Semwal sumit.semwal@linaro.org
Add debugfs support to make it easier to print debug information about the dma-buf buffers.
I like the idea, I don't know if it could be done in a free manner, but for bonus points could we also have the dma-buf fd be obtainable that way from a debugfs entry?
Doing so would allow me to 'steal' a dma-buf from an existing mapping easily, and test against that.
Also I think the name of the device and process that exported the dma-buf would be useful to have as well, even if in case of the device that would mean changing the api slightly to record it.
I was thinking of having a directory structure like this:
/sys/kernel/debug/dma_buf/stats
and then for each dma-buf:
/sys/kernel/debug/dma-buf/exporting_file.c/<number>-fd /sys/kernel/debug/dma-buf/exporting_file.c/<number>-attachments /sys/kernel/debug/dma-buf/exporting_file.c/<number>-info
Opening the fd file would give you back the original fd, or fail with -EIO if refcount was dropped to 0.
Would something like this be doable? I don't know debugfs that well, but I don't see why it wouldn't be,
yeah.. but sort of back-door's the security benefits of an anonymous fd..
BR, -R
If you have access to debugfs you're root, so what stops you from stealing it through a ptrace?
~Maarten