diff options
| author | Alexey Khoroshilov <khoroshilov@ispras.ru> | 2012-09-15 01:29:37 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-09-26 13:20:40 -0700 |
| commit | 221b7b5796b520b51c34c40239d77921ba39225b (patch) | |
| tree | 18a779b98a3872b086461308e49862a0777a0dcb /drivers/char/pcmcia/synclink_cs.c | |
| parent | 08b79dd10bb24f5fb12446d21d32c87a8136c770 (diff) | |
| download | lwn-221b7b5796b520b51c34c40239d77921ba39225b.tar.gz lwn-221b7b5796b520b51c34c40239d77921ba39225b.zip | |
pcmcia: synclink_cs: fix potential tty NULL dereference
tty_port_tty_get() can return NULL after port hangup that may happen anytime.
The patch adds checks that tty_port_tty_get() returns nonNULL around places
where tty is actually used.
I have no actual hardware to test the patch, so I have updated rx side
processing from common sense only.
v2: rx handling updated according Alan Cox feedback.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/char/pcmcia/synclink_cs.c')
| -rw-r--r-- | drivers/char/pcmcia/synclink_cs.c | 20 |
1 files changed, 13 insertions, 7 deletions
diff --git a/drivers/char/pcmcia/synclink_cs.c b/drivers/char/pcmcia/synclink_cs.c index 0a484b4a1b02..a6b8ddea2227 100644 --- a/drivers/char/pcmcia/synclink_cs.c +++ b/drivers/char/pcmcia/synclink_cs.c @@ -891,6 +891,14 @@ static void rx_ready_async(MGSLPC_INFO *info, int tcd, struct tty_struct *tty) int work = 0; struct mgsl_icount *icount = &info->icount; + if (!tty) { + /* tty is not available anymore */ + issue_command(info, CHA, CMD_RXRESET); + if (debug_level >= DEBUG_LEVEL_ISR) + printk("%s(%d):rx_ready_async(tty=NULL)\n",__FILE__,__LINE__); + return; + } + if (tcd) { /* early termination, get FIFO count from RBCL register */ fifo_count = (unsigned char)(read_reg(info, CHA+RBCL) & 0x1f); @@ -980,7 +988,7 @@ static void tx_done(MGSLPC_INFO *info, struct tty_struct *tty) else #endif { - if (tty->stopped || tty->hw_stopped) { + if (tty && (tty->stopped || tty->hw_stopped)) { tx_stop(info); return; } @@ -1000,7 +1008,7 @@ static void tx_ready(MGSLPC_INFO *info, struct tty_struct *tty) if (!info->tx_active) return; } else { - if (tty->stopped || tty->hw_stopped) { + if (tty && (tty->stopped || tty->hw_stopped)) { tx_stop(info); return; } @@ -1050,13 +1058,12 @@ static void cts_change(MGSLPC_INFO *info, struct tty_struct *tty) wake_up_interruptible(&info->status_event_wait_q); wake_up_interruptible(&info->event_wait_q); - if (info->port.flags & ASYNC_CTS_FLOW) { + if (tty && (info->port.flags & ASYNC_CTS_FLOW)) { if (tty->hw_stopped) { if (info->serial_signals & SerialSignal_CTS) { if (debug_level >= DEBUG_LEVEL_ISR) printk("CTS tx start..."); - if (tty) - tty->hw_stopped = 0; + tty->hw_stopped = 0; tx_start(info, tty); info->pending_bh |= BH_TRANSMIT; return; @@ -1065,8 +1072,7 @@ static void cts_change(MGSLPC_INFO *info, struct tty_struct *tty) if (!(info->serial_signals & SerialSignal_CTS)) { if (debug_level >= DEBUG_LEVEL_ISR) printk("CTS tx stop..."); - if (tty) - tty->hw_stopped = 1; + tty->hw_stopped = 1; tx_stop(info); } } |