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authorArnd Bergmann <arnd@arndb.de>2011-07-01 17:30:00 -0700
committerDavid S. Miller <davem@davemloft.net>2011-07-01 17:30:00 -0700
commit6e4e2f811bade330126d4029c88c831784a7efd9 (patch)
tree03d365ae386b9a8f43c24483eb0455a73a96bf48
parent60c2ce2b4facf28f569115a55e1f479eb12bd0f1 (diff)
6pack,mkiss: fix lock inconsistency
Lockdep found a locking inconsistency in the mkiss_close function: > kernel: [ INFO: inconsistent lock state ] > kernel: 2.6.39.1 #3 > kernel: --------------------------------- > kernel: inconsistent {IN-SOFTIRQ-R} -> {SOFTIRQ-ON-W} usage. > kernel: ax25ipd/2813 [HC0[0]:SC0[0]:HE1:SE1] takes: > kernel: (disc_data_lock){+++?.-}, at: [<ffffffffa018552b>] mkiss_close+0x1b/0x90 [mkiss] > kernel: {IN-SOFTIRQ-R} state was registered at: The message hints that disc_data_lock is aquired with softirqs disabled, but does not itself disable softirqs, which can in rare circumstances lead to a deadlock. The same problem is present in the 6pack driver, this patch fixes both by using write_lock_bh instead of write_lock. Reported-by: Bernard F6BVP <f6bvp@free.fr> Tested-by: Bernard F6BVP <f6bvp@free.fr> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Ralf Baechle<ralf@linux-mips.org> Cc: stable@kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/hamradio/6pack.c4
-rw-r--r--drivers/net/hamradio/mkiss.c4
2 files changed, 4 insertions, 4 deletions
diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c
index 3e5d0b6b6516..0d283781bc5e 100644
--- a/drivers/net/hamradio/6pack.c
+++ b/drivers/net/hamradio/6pack.c
@@ -692,10 +692,10 @@ static void sixpack_close(struct tty_struct *tty)
{
struct sixpack *sp;
- write_lock(&disc_data_lock);
+ write_lock_bh(&disc_data_lock);
sp = tty->disc_data;
tty->disc_data = NULL;
- write_unlock(&disc_data_lock);
+ write_unlock_bh(&disc_data_lock);
if (!sp)
return;
diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c
index 4c628393c8b1..bc02968cee16 100644
--- a/drivers/net/hamradio/mkiss.c
+++ b/drivers/net/hamradio/mkiss.c
@@ -813,10 +813,10 @@ static void mkiss_close(struct tty_struct *tty)
{
struct mkiss *ax;
- write_lock(&disc_data_lock);
+ write_lock_bh(&disc_data_lock);
ax = tty->disc_data;
tty->disc_data = NULL;
- write_unlock(&disc_data_lock);
+ write_unlock_bh(&disc_data_lock);
if (!ax)
return;