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| author |   Arnd Bergmann <arnd@arndb.de> | 2011-07-01 17:30:00 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2011-07-01 17:30:00 -0700 |
| commit | 6e4e2f811bade330126d4029c88c831784a7efd9 (patch) | |
| tree | 03d365ae386b9a8f43c24483eb0455a73a96bf48 /drivers/net/hamradio/mkiss.c | |
| parent | Merge branch 'for-davem' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6 (diff) | |
| download | linux-dev-6e4e2f811bade330126d4029c88c831784a7efd9.tar.xz linux-dev-6e4e2f811bade330126d4029c88c831784a7efd9.zip | |
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>
Diffstat (limited to 'drivers/net/hamradio/mkiss.c')
| -rw-r--r-- | drivers/net/hamradio/mkiss.c | 4 |
1 files changed, 2 insertions, 2 deletions
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; |