From adeab1afb7de89555c69aab5ca21300c14af6369 Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Sun, 12 Jul 2009 21:09:20 -0700 Subject: NET: Fix locking issues in PPP, 6pack, mkiss and strip line disciplines. Guido Trentalancia reports: I am trying to use the kiss driver in the Linux kernel that is being shipped with Fedora 10 but unfortunately I get the following oops: mkiss: AX.25 Multikiss, Hans Albas PE1AYX mkiss: ax0: crc mode is auto. ADDRCONF(NETDEV_CHANGE): ax0: link becomes ready ------------[ cut here ]------------ WARNING: at kernel/softirq.c:77 __local_bh_disable+0x2f/0x83() (Not tainted) [...] unloaded: microcode] Pid: 0, comm: swapper Not tainted 2.6.27.25-170.2.72.fc10.i686 #1 [] warn_on_slowpath+0x65/0x8b [] ? _spin_unlock_irqrestore+0x22/0x38 [] ? __enqueue_entity+0xe3/0xeb [] ? enqueue_entity+0x203/0x20b [] ? enqueue_task_fair+0x3b/0x3f [] ? resched_task+0x3a/0x6e [] ? _spin_unlock_irqrestore+0x22/0x38 [] ? _spin_lock_bh+0xb/0x16 [] __local_bh_disable+0x2f/0x83 [] local_bh_disable+0xb/0xd [] _spin_lock_bh+0xb/0x16 [] mkiss_receive_buf+0x2fb/0x3a6 [mkiss] [] flush_to_ldisc+0xf7/0x198 [] tty_flip_buffer_push+0x41/0x51 [] ftdi_process_read+0x375/0x4ad [ftdi_sio] [] ftdi_read_bulk_callback+0x130/0x138 [ftdi_sio] [] usb_hcd_giveback_urb+0x63/0x93 [] uhci_giveback_urb+0xe5/0x15f [] uhci_scan_schedule+0x52e/0x767 [] ? psmouse_handle_byte+0xc/0xe5 [] ? acpi_ev_gpe_detect+0xd6/0xe1 [] uhci_irq+0x110/0x125 [] usb_hcd_irq+0x40/0xa3 [] handle_IRQ_event+0x2f/0x64 [] handle_level_irq+0x74/0xbe [] ? handle_level_irq+0x0/0xbe [] do_IRQ+0xc7/0xfe [] common_interrupt+0x28/0x30 [] ? acpi_idle_enter_simple+0x162/0x19d [] cpuidle_idle_call+0x60/0x92 [] cpu_idle+0x101/0x134 [] rest_init+0x4e/0x50 ======================= ---[ end trace b7cc8076093467ad ]--- ------------[ cut here ]------------ WARNING: at kernel/softirq.c:136 _local_bh_enable_ip+0x3d/0xc4() [...] Pid: 0, comm: swapper Tainted: G W 2.6.27.25-170.2.72.fc10.i686 [] warn_on_slowpath+0x65/0x8b [] ? _spin_unlock_irqrestore+0x22/0x38 [] ? __enqueue_entity+0xe3/0xeb [] ? enqueue_entity+0x203/0x20b [] ? enqueue_task_fair+0x3b/0x3f [] ? resched_task+0x3a/0x6e [] ? _spin_unlock_irqrestore+0x22/0x38 [] ? _spin_lock_bh+0xb/0x16 [] ? mkiss_receive_buf+0x33d/0x3a6 [mkiss] [] _local_bh_enable_ip+0x3d/0xc4 [] local_bh_enable_ip+0x8/0xa [] _spin_unlock_bh+0x11/0x13 [] mkiss_receive_buf+0x33d/0x3a6 [mkiss] [] flush_to_ldisc+0xf7/0x198 [] tty_flip_buffer_push+0x41/0x51 [] ftdi_process_read+0x375/0x4ad [ftdi_sio] [] ftdi_read_bulk_callback+0x130/0x138 [ftdi_sio] [] usb_hcd_giveback_urb+0x63/0x93 [] uhci_giveback_urb+0xe5/0x15f [] uhci_scan_schedule+0x52e/0x767 [] ? psmouse_handle_byte+0xc/0xe5 [] ? acpi_ev_gpe_detect+0xd6/0xe1 [] uhci_irq+0x110/0x125 [] usb_hcd_irq+0x40/0xa3 [] handle_IRQ_event+0x2f/0x64 [] handle_level_irq+0x74/0xbe [] ? handle_level_irq+0x0/0xbe [] do_IRQ+0xc7/0xfe [] common_interrupt+0x28/0x30 [] ? acpi_idle_enter_simple+0x162/0x19d [] cpuidle_idle_call+0x60/0x92 [] cpu_idle+0x101/0x134 [] rest_init+0x4e/0x50 ======================= ---[ end trace b7cc8076093467ad ]--- mkiss: ax0: Trying crc-smack mkiss: ax0: Trying crc-flexnet The issue was, that the locking code in mkiss was assuming it was only ever being called in process or bh context. Fixed by converting the involved locking code to use irq-safe locks. Review of other networking line disciplines shows that 6pack, both sync and async PPP and STRIP have similar issues. The ppp_async one is the most interesting one as it sorts out half of the issue as far back as 2004 in commit http://git.kernel.org/?p=linux/kernel/git/tglx/history.git;a=commitdiff;h=2996d8deaeddd01820691a872550dc0cfba0c37d Signed-off-by: Ralf Baechle Reported-by: Guido Trentalancia Signed-off-by: David S. Miller --- drivers/net/hamradio/6pack.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'drivers/net/hamradio/6pack.c') diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c index 155160052c8b..913a56406594 100644 --- a/drivers/net/hamradio/6pack.c +++ b/drivers/net/hamradio/6pack.c @@ -398,13 +398,14 @@ static DEFINE_RWLOCK(disc_data_lock); static struct sixpack *sp_get(struct tty_struct *tty) { + unsigned long flags; struct sixpack *sp; - read_lock(&disc_data_lock); + read_lock_irqsave(&disc_data_lock, flags); sp = tty->disc_data; if (sp) atomic_inc(&sp->refcnt); - read_unlock(&disc_data_lock); + read_unlock_irqrestore(&disc_data_lock, flags); return sp; } @@ -688,12 +689,13 @@ out: */ static void sixpack_close(struct tty_struct *tty) { + unsigned long flags; struct sixpack *sp; - write_lock(&disc_data_lock); + write_lock_irqsave(&disc_data_lock, flags); sp = tty->disc_data; tty->disc_data = NULL; - write_unlock(&disc_data_lock); + write_unlock_irqrestore(&disc_data_lock, flags); if (!sp) return; -- cgit v1.2.3-59-g8ed1b