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authorArnd Bergmann <arnd@arndb.de>2011-07-01 17:30:00 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2011-07-13 05:29:25 +0200
commit06ce414d4a0811a979a82cddc3e429e6bd704c98 (patch)
tree9ff0ef50bf725b2668d164fa713910f3e3d8bdc6 /drivers
parentd2c7e885624f03cdbba80f124096e5073156969e (diff)
downloadlinux-linaro-stable-06ce414d4a0811a979a82cddc3e429e6bd704c98.tar.gz
6pack,mkiss: fix lock inconsistency
commit 6e4e2f811bade330126d4029c88c831784a7efd9 upstream. 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> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-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 fb588301a05d..0e5b54b2b4d7 100644
--- a/drivers/net/hamradio/6pack.c
+++ b/drivers/net/hamradio/6pack.c
@@ -690,10 +690,10 @@ 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 db4b7f1603f6..6cfc2b484911 100644
--- a/drivers/net/hamradio/mkiss.c
+++ b/drivers/net/hamradio/mkiss.c
@@ -811,10 +811,10 @@ 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;