diff options
| author | Pete Zaitcev <zaitcev@redhat.com> | 2008-11-14 09:47:41 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-12-05 10:55:09 -0800 |
| commit | af4df26152cec2b2d9a1f04872eb9140202ccf13 (patch) | |
| tree | a2d4b12fb7a7e02ca3199d2ce53cfa522c01c4f7 | |
| parent | d38a3218e8e8a74de61c1d5db462d499519aa7da (diff) | |
USB: usbmon: fix read(2)
commit f1c0a2a3aff53698f4855968d576464041d49b39 upstream.
There's a bug in the usbmon binary reader: When using read() to fetch
the packets and a packet's data is partially read, the next read call
will once again return up to len_cap bytes of data. The b_read counter
is not regarded when determining the remaining chunk size.
So, when dumping USB data with "cat /dev/usbmon0 > usbmon.trace" while
reading from a USB storage device and analyzing the dump file
afterwards it will get out of sync after a couple of packets.
Signed-off-by: Ingo van Lil <inguin@gmx.de>
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/usb/mon/mon_bin.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c index 6566fc0a3228..0ada0fc0a698 100644 --- a/drivers/usb/mon/mon_bin.c +++ b/drivers/usb/mon/mon_bin.c @@ -687,7 +687,10 @@ static ssize_t mon_bin_read(struct file *file, char __user *buf, } if (rp->b_read >= sizeof(struct mon_bin_hdr)) { - step_len = min(nbytes, (size_t)ep->len_cap); + step_len = ep->len_cap; + step_len -= rp->b_read - sizeof(struct mon_bin_hdr); + if (step_len > nbytes) + step_len = nbytes; offset = rp->b_out + PKT_SIZE; offset += rp->b_read - sizeof(struct mon_bin_hdr); if (offset >= rp->b_size) |