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To: Dan Carpenter , Suwan Kim Cc: kbuild@lists.01.org, kbuild-all@lists.01.org, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , linux-usb@vger.kernel.org, shuah References: <20191022092839.GD10833@kadam> <20191023071120.GA3061@localhost.localdomain> <20191024194500.GD23523@kadam> From: shuah Message-ID: Date: Thu, 24 Oct 2019 16:52:52 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20191024194500.GD23523@kadam> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/24/19 1:45 PM, Dan Carpenter wrote: > On Wed, Oct 23, 2019 at 04:11:20PM +0900, Suwan Kim wrote: >> On Tue, Oct 22, 2019 at 12:28:39PM +0300, Dan Carpenter wrote: >>> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >>> head: 7d194c2100ad2a6dded545887d02754948ca5241 >>> commit: ea44d190764b4422af4d1c29eaeb9e69e353b406 usbip: Implement SG support to vhci-hcd and stub driver >>> date: 7 weeks ago >>> >>> If you fix the issue, kindly add following tag >>> Reported-by: kbuild test robot >>> Reported-by: Dan Carpenter >>> >>> New smatch warnings: >>> drivers/usb/usbip/stub_rx.c:505 stub_recv_cmd_submit() error: uninitialized symbol 'nents'. >>> >>> Old smatch warnings: >>> drivers/usb/usbip/stub_rx.c:450 stub_recv_xbuff() error: uninitialized symbol 'ret'. >>> >>> # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ea44d190764b4422af4d1c29eaeb9e69e353b406 >>> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git >>> git remote update linus >>> git checkout ea44d190764b4422af4d1c29eaeb9e69e353b406 >>> vim +/nents +505 drivers/usb/usbip/stub_rx.c >>> >>> 4d7b5c7f8ad49b drivers/staging/usbip/stub_rx.c Takahiro Hirofuchi 2008-07-09 453 static void stub_recv_cmd_submit(struct stub_device *sdev, >>> 4d7b5c7f8ad49b drivers/staging/usbip/stub_rx.c Takahiro Hirofuchi 2008-07-09 454 struct usbip_header *pdu) >>> 4d7b5c7f8ad49b drivers/staging/usbip/stub_rx.c Takahiro Hirofuchi 2008-07-09 455 { >>> 4d7b5c7f8ad49b drivers/staging/usbip/stub_rx.c Takahiro Hirofuchi 2008-07-09 456 struct stub_priv *priv; >>> 4d7b5c7f8ad49b drivers/staging/usbip/stub_rx.c Takahiro Hirofuchi 2008-07-09 457 struct usbip_device *ud = &sdev->ud; >>> 2d8f4595d1f275 drivers/staging/usbip/stub_rx.c Max Vozeler 2011-01-12 458 struct usb_device *udev = sdev->udev; >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 459 struct scatterlist *sgl = NULL, *sg; >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 460 void *buffer = NULL; >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 461 unsigned long long buf_len; >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 462 int nents; >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 463 int num_urbs = 1; >>> c6688ef9f29762 drivers/usb/usbip/stub_rx.c Shuah Khan 2017-12-07 464 int pipe = get_pipe(sdev, pdu); >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 465 int use_sg = pdu->u.cmd_submit.transfer_flags & URB_DMA_MAP_SG; >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 466 int support_sg = 1; >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 467 int np = 0; >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 468 int ret, i; >>> 4d7b5c7f8ad49b drivers/staging/usbip/stub_rx.c Takahiro Hirofuchi 2008-07-09 469 >>> 635f545a7e8be7 drivers/usb/usbip/stub_rx.c Shuah Khan 2017-12-07 470 if (pipe == -1) >>> 635f545a7e8be7 drivers/usb/usbip/stub_rx.c Shuah Khan 2017-12-07 471 return; >>> 4d7b5c7f8ad49b drivers/staging/usbip/stub_rx.c Takahiro Hirofuchi 2008-07-09 472 >>> 4d7b5c7f8ad49b drivers/staging/usbip/stub_rx.c Takahiro Hirofuchi 2008-07-09 473 priv = stub_priv_alloc(sdev, pdu); >>> 4d7b5c7f8ad49b drivers/staging/usbip/stub_rx.c Takahiro Hirofuchi 2008-07-09 474 if (!priv) >>> 4d7b5c7f8ad49b drivers/staging/usbip/stub_rx.c Takahiro Hirofuchi 2008-07-09 475 return; >>> 4d7b5c7f8ad49b drivers/staging/usbip/stub_rx.c Takahiro Hirofuchi 2008-07-09 476 >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 477 buf_len = (unsigned long long)pdu->u.cmd_submit.transfer_buffer_length; >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 478 >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 479 /* allocate urb transfer buffer, if needed */ >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 480 if (buf_len) { >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 481 if (use_sg) { >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 482 sgl = sgl_alloc(buf_len, GFP_KERNEL, &nents); >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 483 if (!sgl) >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 484 goto err_malloc; >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 485 } else { >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 486 buffer = kzalloc(buf_len, GFP_KERNEL); >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 487 if (!buffer) >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 488 goto err_malloc; >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 489 } >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 490 } >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 491 >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 492 /* Check if the server's HCD supports SG */ >>> ea44d190764b44 drivers/usb/usbip/stub_rx.c Suwan Kim 2019-08-28 493 if (use_sg && !udev->bus->sg_tablesize) { >>> >>> Smatch thinks "use_sg" can be true when "buf_len" is zero. It's hard >>> to tell if Smatch is right or wrong without more context... >> >> This is a bit strange. The meaning of "use_sg" is that client will >> use scatter-gather and client's urb->num_sgs is not zero. And buffer >> length should not be zero. >> >> usb_sg and buf_len are both client-dependent variables, so I think >> if they have wrong value in the server side, the client must have >> sent use_sg and buf_len with incorrect values. >> >> Did this error occur when compiling? > > Smatch is doing static analysis, yes. > >> If then, Did Smatch also consider vhci tx side? > > I'm not really sure... I can't reproduce the warning because on my > system Smatch doesn't parse usbip_recv() correctly so it ends up > silencing that warning. :/ > Hi Suwan, This is a problem that needs fixing. nents /* allocate urb transfer buffer, if needed */ if (buf_len) { if (use_sg) { sgl = sgl_alloc(buf_len, GFP_KERNEL, &nents); nents gets initialized here by sgl_alloc() if (!sgl) goto err_malloc; } else { buffer = kzalloc(buf_len, GFP_KERNEL); if (!buffer) goto err_malloc; } } /* Check if the server's HCD supports SG */ if (use_sg && !udev->bus->sg_tablesize) { /* * If the server's HCD doesn't support SG, break a single SG * request into several URBs and map each SG list entry to * corresponding URB buffer. The previously allocated SG * list is stored in priv->sgl (If the server's HCD support SG, * SG list is stored only in urb->sg) and it is used as an * indicator that the server split single SG request into * several URBs. Later, priv->sgl is used by stub_complete() and * stub_send_ret_submit() to reassemble the divied URBs. */ support_sg = 0; num_urbs = nents; I think nents will be valid here. Is there need for this additional check here? You can fold this into the previous use_sg check, right after the sg_alloc() success, I would think. priv->completed_urbs = 0; pdu->u.cmd_submit.transfer_flags &= ~URB_DMA_MAP_SG; } thanks, -- Shuah