2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Arnd Bergmann <[email protected]> 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 <[email protected]> Tested-by: Bernard F6BVP <[email protected]> Signed-off-by: Arnd Bergmann <[email protected]> Acked-by: Ralf Baechle<[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Andi Kleen <[email protected]> --- drivers/net/hamradio/6pack.c | 4 ++-- drivers/net/hamradio/mkiss.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) Index: linux-2.6.35.y/drivers/net/hamradio/6pack.c =================================================================== --- linux-2.6.35.y.orig/drivers/net/hamradio/6pack.c +++ linux-2.6.35.y/drivers/net/hamradio/6pack.c @@ -692,10 +692,10 @@ static void sixpack_close(struct tty_str { 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; Index: linux-2.6.35.y/drivers/net/hamradio/mkiss.c =================================================================== --- linux-2.6.35.y.orig/drivers/net/hamradio/mkiss.c +++ linux-2.6.35.y/drivers/net/hamradio/mkiss.c @@ -813,10 +813,10 @@ static void mkiss_close(struct tty_struc { 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; _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
