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([2620:10d:c092:600::1:b576]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-475c4281314sm51788185e9.4.2025.10.22.09.51.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Oct 2025 09:51:48 -0700 (PDT) Message-ID: <355c371d-124d-4414-9af4-fd9247692db3@gmail.com> Date: Wed, 22 Oct 2025 17:53:13 +0100 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] io_uring: check for user passing 0 nr_submit To: Jeff Moyer Cc: io-uring@vger.kernel.org References: <9f43c61b36bc5976e7629663b4558ce439bccc64.1760609826.git.asml.silence@gmail.com> Content-Language: en-US From: Pavel Begunkov In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 10/22/25 14:49, Jeff Moyer wrote: > Pavel Begunkov 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 >> --- >> >> 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