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Wed, 15 Apr 2026 13:24:42 -0700 (PDT) Received: from [10.0.0.169] ([72.170.223.83]) by smtp.gmail.com with ESMTPSA id 5614622812f47-4797a36800bsm1514761b6e.5.2026.04.15.13.24.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 15 Apr 2026 13:24:41 -0700 (PDT) Message-ID: <499e9c02-3600-441c-bc8c-6ab41128d2bd@kernel.dk> Date: Wed, 15 Apr 2026 14:24:33 -0600 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: [bug report] io_uring/tctx: clean up __io_uring_add_tctx_node() error handling To: Dan Carpenter Cc: io-uring@vger.kernel.org References: Content-Language: en-US From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/13/26 3:20 AM, Dan Carpenter wrote: > Hello Jens Axboe, > > Commit 7880174e1e5e ("io_uring/tctx: clean up > __io_uring_add_tctx_node() error handling") from Apr 8, 2026 > (linux-next), leads to the following Smatch static checker warning: > > io_uring/tctx.c:174 __io_uring_add_tctx_node() > error: we previously assumed 'tctx->io_wq' could be null (see line 164) > > io_uring/tctx.c > 139 int __io_uring_add_tctx_node(struct io_ring_ctx *ctx) > 140 { > 141 struct io_uring_task *tctx = current->io_uring; > 142 int ret; > 143 > 144 if (unlikely(!tctx)) { > 145 tctx = io_uring_alloc_task_context(current, ctx); > 146 if (IS_ERR(tctx)) > 147 return PTR_ERR(tctx); > 148 > 149 if (ctx->int_flags & IO_RING_F_IOWQ_LIMITS_SET) { > 150 unsigned int limits[2] = { ctx->iowq_limits[0], > 151 ctx->iowq_limits[1], }; > 152 > 153 ret = io_wq_max_workers(tctx->io_wq, limits); > 154 if (ret) > 155 goto err_free; > 156 } > 157 } > 158 > 159 /* > 160 * Re-activate io-wq keepalive on any new io_uring usage. The wq may have > 161 * been marked for idle-exit when the task temporarily had no active > 162 * io_uring instances. > 163 */ > 164 if (tctx->io_wq) > ^^^^^^^^^^^ > This assumes ->io_wq can be NULL > > 165 io_wq_set_exit_on_idle(tctx->io_wq, false); > 166 > 167 ret = io_tctx_install_node(ctx, tctx); > 168 if (!ret) { > 169 current->io_uring = tctx; > 170 return 0; > 171 } > 172 if (!current->io_uring) { > 173 err_free: > --> 174 io_wq_put_and_exit(tctx->io_wq); > ^^^^^^^^^^^ > Dereferenced without checking > > 175 percpu_counter_destroy(&tctx->inflight); > 176 kfree(tctx); > 177 } > 178 return ret; > 179 } > > This email is a free service from the Smatch-CI project [smatch.sf.net]. Thanks, I'll make them consistent. -- Jens Axboe