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Wed, 08 Apr 2026 05:49:24 -0700 (PDT) Message-ID: <7850ad0e-5124-4165-be96-3c5b4af0b723@kernel.dk> Date: Wed, 8 Apr 2026 06:49:23 -0600 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] io_uring/rsrc: use io_cache_free for node in io_buffer_register_bvec error path To: Pavel Begunkov , KobaK Cc: Keith Busch , Ming Lei , io-uring@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260408065408.2017967-1-kobak@nvidia.com> <20260408065408.2017967-3-kobak@nvidia.com> Content-Language: en-US From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/8/26 2:35 AM, Pavel Begunkov wrote: > On 4/8/26 07:54, KobaK wrote: >> From: Koba Ko >> >> 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 >> --- >> 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