From 328be395a396b1333b56e04571365dc614c96e46 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Tue, 25 May 2010 11:37:17 +0200 Subject: [PATCH] TTY/n_gsm: potential double lock In gsm_dlci_data_kick() we call gsm_dlci_data_sweep() with the "gsm->tx_lock" held so we can't lock it again inside gsm_dlci_data_sweep(). I removed that lock from and added one to gsmld_write_wakeup() instead. The sweep function is only called from those two places. Signed-off-by: Dan Carpenter Acked-by: Alan Cox Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/char/n_gsm.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/char/n_gsm.c b/drivers/char/n_gsm.c index c4161d5e053..e4089c432f1 100644 --- a/drivers/char/n_gsm.c +++ b/drivers/char/n_gsm.c @@ -904,9 +904,7 @@ static void gsm_dlci_data_sweep(struct gsm_mux *gsm) int len; /* Priority ordering: We should do priority with RR of the groups */ int i = 1; - unsigned long flags; - spin_lock_irqsave(&gsm->tx_lock, flags); while (i < NUM_DLCI) { struct gsm_dlci *dlci; @@ -927,7 +925,6 @@ static void gsm_dlci_data_sweep(struct gsm_mux *gsm) if (len == 0) i++; } - spin_unlock_irqrestore(&gsm->tx_lock, flags); } /** @@ -2230,12 +2227,16 @@ static int gsmld_open(struct tty_struct *tty) static void gsmld_write_wakeup(struct tty_struct *tty) { struct gsm_mux *gsm = tty->disc_data; + unsigned long flags; /* Queue poll */ clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); gsm_data_kick(gsm); - if (gsm->tx_bytes < TX_THRESH_LO) + if (gsm->tx_bytes < TX_THRESH_LO) { + spin_lock_irqsave(&gsm->tx_lock, flags); gsm_dlci_data_sweep(gsm); + spin_unlock_irqrestore(&gsm->tx_lock, flags); + } } /** -- 2.39.3