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

[Pavel Begunkov <asml.silence@gmail.com>]

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.


>> 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);
> 

-- 
Pavel Begunkov