Re: drivers/usb/usbip/vhci_tx.c:150:8-18: ERROR: reference preceded by free on line 150 (fwd)

From: Suwan Kim
Date: Mon Oct 21 2019 - 05:43:51 EST

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In reply to: Julia Lawall: "drivers/usb/usbip/vhci_tx.c:150:8-18: ERROR: reference preceded by free on line 150 (fwd)"
Next in thread: Julia Lawall: "Re: drivers/usb/usbip/vhci_tx.c:150:8-18: ERROR: reference preceded by free on line 150 (fwd)"
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On Sat, Oct 19, 2019 at 07:49:29PM +0200, Julia Lawall wrote:
> Is it guaranteed that if usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS (line
> 123) is true on one iteration, then it will be true on all iterations? If
> not, then it could be good to set iso_buffer to NULL after the kfree on
> line 150.
>

It is not always true on all iteration because URB on each iteration
can have different type of pipe. So, I think you are right.
Thanks for reporting this.

I think it seems better to move the declaration of
usbip_iso_packet_descriptor into the while loop.

Could you send a patch to Shuah? Or should I send?

Regards
Suwan Kim

> julia
>
> ---------- Forwarded message ----------
> Date: Sun, 20 Oct 2019 01:40:11 +0800
> From: kbuild test robot <lkp@xxxxxxxxx>
> To: kbuild@xxxxxxxxxxxx
> Cc: Julia Lawall <julia.lawall@xxxxxxx>
> Subject: drivers/usb/usbip/vhci_tx.c:150:8-18: ERROR: reference preceded by free
> on line 150
>
> CC: kbuild-all@xxxxxxxxxxxx
> CC: linux-kernel@xxxxxxxxxxxxxxx
> CC: "Greg Kroah-Hartman" <gregkh@xxxxxxxxxxxxxxxxxxx>
>
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: 998d75510e373aab5644d777d3b058312d550159
> commit: ea44d190764b4422af4d1c29eaeb9e69e353b406 usbip: Implement SG support to vhci-hcd and stub driver
> date: 7 weeks ago
> :::::: branch date: 7 hours ago
> :::::: commit date: 7 weeks ago
>
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> Reported-by: Julia Lawall <julia.lawall@xxxxxxx>
>
> >> drivers/usb/usbip/vhci_tx.c:150:8-18: ERROR: reference preceded by free on line 150
> drivers/usb/usbip/vhci_tx.c:159:7-17: ERROR: reference preceded by free on line 150
>
> # 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 +150 drivers/usb/usbip/vhci_tx.c
>
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 51
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 52 static int vhci_send_cmd_submit(struct vhci_device *vdev)
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 53 {
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 54 struct usbip_iso_packet_descriptor *iso_buffer = NULL;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 55 struct vhci_priv *priv = NULL;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 56 struct scatterlist *sg;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 57
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 58 struct msghdr msg;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 59 struct kvec *iov;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 60 size_t txsize;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 61
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 62 size_t total_size = 0;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 63 int iovnum;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 64 int err = -ENOMEM;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 65 int i;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 66
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 67 while ((priv = dequeue_from_priv_tx(vdev)) != NULL) {
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 68 int ret;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 69 struct urb *urb = priv->urb;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 70 struct usbip_header pdu_header;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 71
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 72 txsize = 0;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 73 memset(&pdu_header, 0, sizeof(pdu_header));
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 74 memset(&msg, 0, sizeof(msg));
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 75 memset(&iov, 0, sizeof(iov));
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 76
> 8272d099d05f7a drivers/usb/usbip/vhci_tx.c Shuah Khan 2017-12-18 77 usbip_dbg_vhci_tx("setup txdata urb seqnum %lu\n",
> 8272d099d05f7a drivers/usb/usbip/vhci_tx.c Shuah Khan 2017-12-18 78 priv->seqnum);
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 79
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 80 if (urb->num_sgs && usb_pipeout(urb->pipe))
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 81 iovnum = 2 + urb->num_sgs;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 82 else
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 83 iovnum = 3;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 84
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 85 iov = kcalloc(iovnum, sizeof(*iov), GFP_KERNEL);
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 86 if (!iov) {
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 87 usbip_event_add(&vdev->ud, SDEV_EVENT_ERROR_MALLOC);
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 88 return -ENOMEM;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 89 }
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 90
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 91 if (urb->num_sgs)
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 92 urb->transfer_flags |= URB_DMA_MAP_SG;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 93
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 94 /* 1. setup usbip_header */
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 95 setup_cmd_submit_pdu(&pdu_header, urb);
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 96 usbip_header_correct_endian(&pdu_header, 1);
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 97 iovnum = 0;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 98
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 99 iov[iovnum].iov_base = &pdu_header;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 100 iov[iovnum].iov_len = sizeof(pdu_header);
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 101 txsize += sizeof(pdu_header);
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 102 iovnum++;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 103
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 104 /* 2. setup transfer buffer */
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 105 if (!usb_pipein(urb->pipe) && urb->transfer_buffer_length > 0) {
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 106 if (urb->num_sgs &&
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 107 !usb_endpoint_xfer_isoc(&urb->ep->desc)) {
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 108 for_each_sg(urb->sg, sg, urb->num_sgs, i) {
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 109 iov[iovnum].iov_base = sg_virt(sg);
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 110 iov[iovnum].iov_len = sg->length;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 111 iovnum++;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 112 }
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 113 } else {
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 114 iov[iovnum].iov_base = urb->transfer_buffer;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 115 iov[iovnum].iov_len =
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 116 urb->transfer_buffer_length;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 117 iovnum++;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 118 }
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 119 txsize += urb->transfer_buffer_length;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 120 }
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 121
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 122 /* 3. setup iso_packet_descriptor */
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 123 if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 124 ssize_t len = 0;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 125
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 126 iso_buffer = usbip_alloc_iso_desc_pdu(urb, &len);
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 127 if (!iso_buffer) {
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 128 usbip_event_add(&vdev->ud,
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 129 SDEV_EVENT_ERROR_MALLOC);
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 130 goto err_iso_buffer;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 131 }
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 132
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 133 iov[iovnum].iov_base = iso_buffer;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 134 iov[iovnum].iov_len = len;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 135 iovnum++;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 136 txsize += len;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 137 }
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 138
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 139 ret = kernel_sendmsg(vdev->ud.tcp_socket, &msg, iov, iovnum,
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 140 txsize);
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 141 if (ret != txsize) {
> 1a4b6f66285785 drivers/staging/usbip/vhci_tx.c matt mooney 2011-05-19 142 pr_err("sendmsg failed!, ret=%d for %zd\n", ret,
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 143 txsize);
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 144 usbip_event_add(&vdev->ud, VDEV_EVENT_ERROR_TCP);
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 145 err = -EPIPE;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 146 goto err_tx;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 147 }
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 148
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 149 kfree(iov);
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 @150 kfree(iso_buffer);
> b8868e45c5f895 drivers/staging/usbip/vhci_tx.c Brian G. Merrell 2009-07-21 151 usbip_dbg_vhci_tx("send txdata\n");
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 152
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 153 total_size += txsize;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 154 }
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 155
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 156 return total_size;
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 157
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 158 err_tx:
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 159 kfree(iso_buffer);
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 160 err_iso_buffer:
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 161 kfree(iov);
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 162
> ea44d190764b44 drivers/usb/usbip/vhci_tx.c Suwan Kim 2019-08-28 163 return err;
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 164 }
> 04679b3489e048 drivers/staging/usbip/vhci_tx.c Takahiro Hirofuchi 2008-07-09 165
>
> :::::: The code at line 150 was first introduced by commit
> :::::: 04679b3489e048cd5dae79e050a3afed8e4e42b6 Staging: USB/IP: add client driver
>
> :::::: TO: Takahiro Hirofuchi <hirofuchi@xxxxxxxxxxxxxxxxxxxxx>
> :::::: CC: Greg Kroah-Hartman <gregkh@xxxxxxx>
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation

Next message: David Hildenbrand: "Re: [PATCH v2 2/2] mm/memory-failure.c: Don't access uninitialized memmaps in memory_failure()"
Previous message: Naoya Horiguchi: "[PATCH] mm,hwpoison: introduce MF_MSG_UNSPLIT_THP"
In reply to: Julia Lawall: "drivers/usb/usbip/vhci_tx.c:150:8-18: ERROR: reference preceded by free on line 150 (fwd)"
Next in thread: Julia Lawall: "Re: drivers/usb/usbip/vhci_tx.c:150:8-18: ERROR: reference preceded by free on line 150 (fwd)"
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