Handle null old_termios in ftdi_set_termios() calls from uart_resume_port().
Signed-off-by: Andrew Worsley <amworsley@xxxxxxxxx>
---
Much thanks to Dan Carpenter for pointing this issue out, although my
testing didn't trigger the issue, I think it's much better to avoid it.
For people interested in reproducing this issue I have some more details.
It doesn't really make sense to me but for the record here it is.
Examing the strace -v output we have bash generating several ioctl()s on
each typing of the command line which was the test that produced the issue
on an intermittent basis - say 1 out 3-5 attempts:
uname -a
of which the following might be most relevant:
The only changes I can see are:
c_iflags 0400 = -ICRNL
c_lflags 02 = -ICANON, 010 = -ECHO
Perhaps this is causing the fairly empty ftdi_set_termios() calls?
ioctl() calls:
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {
c_iflags=0x1500, c_oflags=0x5, c_cflags=0x1cb2, c_lflags=0xa3b, c_line=0,
c_cc="\x03\x1c\x7f\x15\x04\x00\x01\x00\x11\x13\x1a\x00\x12\x0f\x17\x16\x00\x00\x00"})
= 0
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {
c_iflags=0x1500, c_oflags=0x5, c_cflags=0x1cb2, c_lflags=0xa3b, c_line=0,
c_cc="\x03\x1c\x7f\x15\x04\x00\x01\x00\x11\x13\x1a\x00\x12\x0f\x17\x16\x00\x00\x00"})
= 0
ioctl(0, SNDCTL_TMR_STOP or TCSETSW, {
c_iflags=0x1400, c_oflags=0x5, c_cflags=0x1cb2, c_lflags=0xa31, c_line=0,
c_cc[VMIN]=1, c_cc[VTIME]=0,
c_cc="\x03\x1c\x7f\x15\x04\x00\x01\x00\x11\x13\x1a\x00\x12\x0f\x17\x00\x00\x00\x00"})
= 0
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {
c_iflags=0x1400, c_oflags=0x5, c_cflags=0x1cb2, c_lflags=0xa31, c_line=0,
c_cc[VMIN]=1, c_cc[VTIME]=0,
c_cc="\x03\x1c\x7f\x15\x04\x00\x01\x00\x11\x13\x1a\x00\x12\x0f\x17\x00\x00\x00\x00"})
= 0
> bash --version
GNU bash, version 3.2.39(1)-release (i486-pc-linux-gnu)
drivers/usb/serial/ftdi_sio.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index bd4298b..13e4ecc 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -2104,6 +2104,9 @@ static void ftdi_set_termios(struct tty_struct *tty,
cflag = termios->c_cflag;
+ if (old_termios == 0)
+ goto no_skip;
+
if (old_termios->c_cflag == termios->c_cflag
&& old_termios->c_ispeed == termios->c_ispeed
&& old_termios->c_ospeed == termios->c_ospeed)
@@ -2117,6 +2120,7 @@ static void ftdi_set_termios(struct tty_struct *tty,
(termios->c_cflag & (CSIZE|PARODD|PARENB|CMSPAR|CSTOPB)))
goto no_data_parity_stop_changes;
+no_skip:
/* Set number of data bits, parity, stop bits */
urb_value = 0;
--
1.7.2.5
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