Re: Review patches of user space kprobe

[Prasanna S Panchamukhi <prasanna at in dot ibm dot com>]

> >>User space probes support insertion of probes on dynamically linked libraries
> >>and even probes can be inserted on the text pages that are not even loaded
> >>into the memory.
> It doesn't resolve case b). 
> 

Need to look how to support such cases.

> 
> >>
> >>>3) Can function register_userspace_probe do not call register_kprobe? I =
> >>>think it's not necessary. It's just my feeling. It's up to you to make =
> >>>decision. :)
> >>
> >>register_kprobe already does most of what userspace probe registeration needs.
> Function register_kprobe is not big. Current register_userspace_probe calls register_kprobe, then register_kprobe calls back to uprobe-specific functions. It looks confusing. Why not to just bypass register_kprobe?
> 

Let me check how the code looks if we bypass register_kprobe().

> >>
> >>could you please elaborate this.
> Under smp environment, if a page (inode,offset) is mapped to the address spaces of many processes, then when a uprobe is registered on the page, uprobe->vma is just point to one of them. Then, insert_kprobe_user=>arch_arm_uprobe=>flush_icache_user_range, only this vma (or address space) is flushed.
> 
At present only the vma containing the page is flused, if the pages are present
on other vmas, even the probes should be inserted on such pages and those vma
need to be flused. 

Thanks
Prasanna
-- 
Prasanna S Panchamukhi
Linux Technology Center
India Software Labs, IBM Bangalore
Email: prasanna@in.ibm.com
Ph: 91-80-25044636