Re: [BUG] io_uring: defer logic based on shared data

[Jens Axboe]

On 10/25/19 10:03 AM, Jens Axboe wrote:
> On 10/25/19 3:55 AM, Pavel Begunkov wrote:
>> I found 2 problems with __io_sequence_defer().
>>
>> 1. it uses @sq_dropped, but doesn't consider @cq_overflow
>> 2. @sq_dropped and @cq_overflow are write-shared with userspace, so
>> it can be maliciously changed.
>>
>> see sent liburing test (test/defer *_hung()), which left an unkillable
>> process for me
> 
> OK, how about the below. I'll split this in two, as it's really two
> separate fixes.

Patch 1:

http://git.kernel.dk/cgit/linux-block/commit/?h=for-linus&id=9a9a21d9cf65cb621cce4052a4527868a80009ad

and patch 2:

http://git.kernel.dk/cgit/linux-block/commit/?h=for-linus&id=ed348662f74c4f63537b3c188585e39cdea22713

Let me know what you think, and if/when I can add your reviewed/test-by
to them.

-- 
Jens Axboe