On Fri, 08 Apr 2016 19:23:45 +0200,
Marcel Holtmann wrote:
>
> Hi Jiri,
>
> > The write handler allocates skbs and queues them into data->readq.
> > Read side should read them, if there is any. If there is none, skbs
> > should be dropped by hdev->flush. But this happens only if the device
> > is HCI_UP, i.e. hdev->power_on work was triggered already. When it was
> > not, skbs stay allocated in the queue when /dev/vhci is closed. So
> > purge the queue in ->release.
> >
> > Program to reproduce:
> > #include <err.h>
> > #include <fcntl.h>
> > #include <stdio.h>
> > #include <unistd.h>
> >
> > #include <sys/stat.h>
> > #include <sys/types.h>
> > #include <sys/uio.h>
> >
> > int main()
> > {
> > char buf[] = { 0xff, 0 };
> > struct iovec iov = {
> > .iov_base = buf,
> > .iov_len = sizeof(buf),
> > };
> > int fd;
> >
> > while (1) {
> > fd = open("/dev/vhci", O_RDWR);
> > if (fd < 0)
> > err(1, "open");
> >
> > usleep(50);
> >
> > if (writev(fd, &iov, 1) < 0)
> > err(1, "writev");
> >
> > usleep(50);
> >
> > close(fd);
> > }
> >
> > return 0;
> > }
> >
> > Result:
> > kmemleak: 4609 new suspected memory leaks
> > unreferenced object 0xffff88059f4d5440 (size 232):
> > comm "vhci", pid 1084, jiffies 4294912542 (age 37569.296s)
> > hex dump (first 32 bytes):
> > 20 f0 23 87 05 88 ff ff 20 f0 23 87 05 88 ff ff .#..... .#.....
> > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> > backtrace:
> > ...
> > [<ffffffff81ece010>] __alloc_skb+0x0/0x5a0
> > [<ffffffffa021886c>] vhci_create_device+0x5c/0x580 [hci_vhci]
> > [<ffffffffa0219436>] vhci_write+0x306/0x4c8 [hci_vhci]
> >
> > Fixes: 23424c0d31 (Bluetooth: Add support creating virtual AMP controllers)
> > Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
> > Cc: Marcel Holtmann <marcel@xxxxxxxxxxxx>
> > Cc: Gustavo Padovan <gustavo@xxxxxxxxxxx>
> > Cc: Johan Hedberg <johan.hedberg@xxxxxxxxx>
> > Cc: <linux-bluetooth@xxxxxxxxxxxxxxx>
> > Cc: stable 3.13+ <stable@xxxxxxxxxxxxxxx>
> > ---
> > drivers/bluetooth/hci_vhci.c | 1 +
> > 1 file changed, 1 insertion(+)
>
> patch has been applied to bluetooth-next tree.
Could you check another race of vhci mentioned in the thread?
https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1106134.html
If the suggested fix is OK, I'll submit a properly cooked patch.
thanks,
Takashi
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