Re: [PATCH 5/8] trace_uprobe: Support SDT markers having reference count (semaphore)

[Ravi Bangoria]

On 03/16/2018 05:09 PM, Oleg Nesterov wrote:
> On 03/16, Ravi Bangoria wrote:
>> On 03/15/2018 08:00 PM, Oleg Nesterov wrote:
>>> Note to mention that sdt_find_vma() can return NULL but the callers do
>>> vma_offset_to_vaddr(vma) without any check.
>> If the "mm" we are passing to sdt_find_vma() is returned by
>> uprobe_build_map_info(ref_ctr_offset), sdt_find_vma() must
>> _not_ return NULL.
> Not at all.
>
> Once build_map_info() returns any mapping can go away. Otherwise, why do
> you think the caller has to take ->mmap_sem and use find_vma()? If you
> were right, build_map_info() could just return the list of vma's instead
> of list of mm's.

Oh.. okay.. I was under wrong impression then. Will add a check there.

Thanks for the review :)
Ravi