Re: [PATCH v2] io_uring: check for user passing 0 nr_submit

[Jeff Moyer <jmoyer@redhat.com>]

Pavel Begunkov <asml.silence@gmail.com> writes:

> On 10/22/25 14:49, Jeff Moyer wrote:
>> Pavel Begunkov <asml.silence@gmail.com> writes:
>> 
>>> io_submit_sqes() shouldn't be stepping into its main loop when there is
>>> nothing to submit, i.e. nr=0. Fix 0 submission queue entries checks,
>>> which should follow after all user input truncations.
>> I see two callers of io_submit_sqes, and neither of them will pass 0
>> for
>> nr.  What am I missing?
>
> You're right, we can drop the fixes/stable part. It's still
> good to have as it's handled not in the best way.

Agreed.

Cheers,
Jeff

>
>
>>> Cc: stable@vger.kernel.org
>>> Fixes: 6962980947e2b ("io_uring: restructure submit sqes to_submit checks")
>>> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
>>> ---
>>>
>>> v2: split out of the series with extra tags, no functional changes
>>>
>>>   io_uring/io_uring.c | 5 +++--
>>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
>>> index 820ef0527666..ee04ab9bf968 100644
>>> --- a/io_uring/io_uring.c
>>> +++ b/io_uring/io_uring.c
>>> @@ -2422,10 +2422,11 @@ int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
>>>   	unsigned int left;
>>>   	int ret;
>>>   +	entries = min(nr, entries);
>>>   	if (unlikely(!entries))
>>>   		return 0;
>>> -	/* make sure SQ entry isn't read before tail */
>>> -	ret = left = min(nr, entries);
>>> +
>>> +	ret = left = entries;
>>>   	io_get_task_refs(left);
>>>   	io_submit_state_start(&ctx->submit_state, left);
>>