The patch titled
tty/n_gsm: potential double lock
has been added to the -mm tree. Its filename is
tty-n_gsm-potential-double-lock.patch
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------------------------------------------------------
Subject: tty/n_gsm: potential double lock
From: Dan Carpenter <error27@xxxxxxxxx>
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 <error27@xxxxxxxxx>
Acked-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/char/n_gsm.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff -puN drivers/char/n_gsm.c~tty-n_gsm-potential-double-lock drivers/char/n_gsm.c
--- a/drivers/char/n_gsm.c~tty-n_gsm-potential-double-lock
+++ a/drivers/char/n_gsm.c
@@ -904,9 +904,7 @@ static void gsm_dlci_data_sweep(struct g
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 g
if (len == 0)
i++;
}
- spin_unlock_irqrestore(&gsm->tx_lock, flags);
}
/**
@@ -2230,12 +2227,16 @@ static int gsmld_open(struct tty_struct
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);
+ }
}
/**
_
Patches currently in -mm which might be from error27@xxxxxxxxx are
origin.patch
proc-cleanup-remove-unused-assignments.patch
linux-next.patch
tty-n_gsm-potential-double-lock.patch
mtd-sst25l-check-for-null-consistently.patch
scsi-remove-superfluous-null-pointer-check-from-scsi_kill_request.patch
padata-add-parenthesis-in-max_seq_nr-macro.patch
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