Re: [PATCH 2/3] io_uring/rsrc: use io_cache_free for node in io_buffer_register_bvec error path

[Jens Axboe]

On 4/8/26 2:35 AM, Pavel Begunkov wrote:
> On 4/8/26 07:54, KobaK wrote:
>> From: Koba Ko <kobak@xxxxxxxxxx>
>>
>> io_buffer_register_bvec() allocates the rsrc node via
>> io_rsrc_node_alloc() which pulls from ctx->node_cache. On imu allocation
>> failure, the node is freed with raw kfree() instead of
>> io_cache_free(&ctx->node_cache, node), bypassing the cache return path
>> and wasting a reuse opportunity. Every other error path in this file
>> correctly uses io_cache_free for nodes.
>>
>> Fixes: 27cb27b6d5ea4 ("io_uring: add support for kernel registered bvecs")
>> Signed-off-by: Koba Ko <kobak@xxxxxxxxxx>
>> ---
>>   io_uring/rsrc.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
>> index 1b96ab5e98c99..6f46cf9cd13d7 100644
>> --- a/io_uring/rsrc.c
>> +++ b/io_uring/rsrc.c
>> @@ -961,7 +961,7 @@ int io_buffer_register_bvec(struct io_uring_cmd *cmd, struct request *rq,
>>        */
>>       imu = io_alloc_imu(ctx, blk_rq_nr_phys_segments(rq));
>>       if (!imu) {
>> -        kfree(node);
>> +        io_cache_free(&ctx->node_cache, node);
> 
> Looks like it was already patched a week ago

Indeed, and main motivation was to eliminate reports like this, where
(clearly) an LLM spotted the "problem" even if there is none. Guess that
was a good move, just need it to land so that we don't need to waste
time on this again.

Nobody cares about "wasting a reuse opportunity" in an error path, any
human would recognize that.

-- 
Jens Axboe