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authorAndre Guedes <andre.guedes@openbossa.org>2011-07-07 10:30:35 -0300
committerGustavo F. Padovan <padovan@profusion.mobi>2011-07-07 14:28:12 -0300
commit8aded7110a5625bc00aef05e94dd4b1a9cf3605f (patch)
treeea84fa4336bb56034a29e225b2c221cdd7c71673 /net/bluetooth
parent2e65c9d2c5206eb24439f2dd2daa2f6702df358e (diff)
downloadlwn-8aded7110a5625bc00aef05e94dd4b1a9cf3605f.tar.gz
lwn-8aded7110a5625bc00aef05e94dd4b1a9cf3605f.zip
Bluetooth: Fix potential deadlock in hci_core
Since hdev->lock may be acquired by threads runnning in interrupt context, all threads running in process context should disable local bottom halve before locking hdev->lock. This can be done by using hci_dev_lock_bh macro. This way, we avoid potencial deadlocks like this one reported by CONFIG_PROVE_LOCKING=y. [ 304.788780] ================================= [ 304.789686] [ INFO: inconsistent lock state ] [ 304.789686] 2.6.39+ #1 [ 304.789686] --------------------------------- [ 304.789686] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [ 304.789686] ksoftirqd/0/3 [HC0[0]:SC1[1]:HE1:SE0] takes: [ 304.789686] (&(&hdev->lock)->rlock){+.?...}, at: [<ffffffffa000bbfe>] hci_conn_check_pending+0x38/0x76 [bluetooth] [ 304.789686] {SOFTIRQ-ON-W} state was registered at: [ 304.789686] [<ffffffff8105188b>] __lock_acquire+0x347/0xd52 [ 304.789686] [<ffffffff810526ac>] lock_acquire+0x8a/0xa7 [ 304.789686] [<ffffffff812b3758>] _raw_spin_lock+0x2c/0x3b [ 304.789686] [<ffffffffa0009cf0>] hci_blacklist_del+0x1f/0x8a [bluetooth] [ 304.789686] [<ffffffffa00139fd>] hci_sock_ioctl+0x2d9/0x314 [bluetooth] [ 304.789686] [<ffffffff812197d8>] sock_ioctl+0x1f2/0x214 [ 304.789686] [<ffffffff810b0fd6>] do_vfs_ioctl+0x46c/0x4ad [ 304.789686] [<ffffffff810b1059>] sys_ioctl+0x42/0x65 [ 304.789686] [<ffffffff812b4892>] system_call_fastpath+0x16/0x1b [ 304.789686] irq event stamp: 9768 [ 304.789686] hardirqs last enabled at (9768): [<ffffffff812b40d4>] restore_args+0x0/0x30 [ 304.789686] hardirqs last disabled at (9767): [<ffffffff812b3f6a>] save_args+0x6a/0x70 [ 304.789686] softirqs last enabled at (9726): [<ffffffff8102fa9b>] __do_softirq+0x129/0x13f [ 304.789686] softirqs last disabled at (9739): [<ffffffff8102fb33>] run_ksoftirqd+0x82/0x133 [ 304.789686] [ 304.789686] other info that might help us debug this: [ 304.789686] Possible unsafe locking scenario: [ 304.789686] [ 304.789686] CPU0 [ 304.789686] ---- [ 304.789686] lock(&(&hdev->lock)->rlock); [ 304.789686] <Interrupt> [ 304.789686] lock(&(&hdev->lock)->rlock); [ 304.789686] [ 304.789686] *** DEADLOCK *** [ 304.789686] [ 304.789686] 1 lock held by ksoftirqd/0/3: [ 304.789686] #0: (hci_task_lock){++.-..}, at: [<ffffffffa0008353>] hci_rx_task+0x49/0x2f3 [bluetooth] [ 304.789686] [ 304.789686] stack backtrace: [ 304.789686] Pid: 3, comm: ksoftirqd/0 Not tainted 2.6.39+ #1 [ 304.789686] Call Trace: [ 304.789686] [<ffffffff812ae901>] print_usage_bug+0x1e7/0x1f8 [ 304.789686] [<ffffffff8100a796>] ? save_stack_trace+0x27/0x44 [ 304.789686] [<ffffffff8104fc3f>] ? print_irq_inversion_bug.part.26+0x19a/0x19a [ 304.789686] [<ffffffff810504bb>] mark_lock+0x106/0x258 [ 304.789686] [<ffffffff812b40d4>] ? retint_restore_args+0x13/0x13 [ 304.789686] [<ffffffff81051817>] __lock_acquire+0x2d3/0xd52 [ 304.789686] [<ffffffff8102be73>] ? vprintk+0x3ab/0x3d7 [ 304.789686] [<ffffffff812ae126>] ? printk+0x3c/0x3e [ 304.789686] [<ffffffff810526ac>] lock_acquire+0x8a/0xa7 [ 304.789686] [<ffffffffa000bbfe>] ? hci_conn_check_pending+0x38/0x76 [bluetooth] [ 304.789686] [<ffffffff811601c6>] ? __dynamic_pr_debug+0x10c/0x11a [ 304.789686] [<ffffffff812b3758>] _raw_spin_lock+0x2c/0x3b [ 304.789686] [<ffffffffa000bbfe>] ? hci_conn_check_pending+0x38/0x76 [bluetooth] [ 304.789686] [<ffffffffa000bbfe>] hci_conn_check_pending+0x38/0x76 [bluetooth] [ 304.789686] [<ffffffffa000c561>] hci_event_packet+0x38e/0x3e12 [bluetooth] [ 304.789686] [<ffffffff81052615>] ? lock_release+0x16c/0x179 [ 304.789686] [<ffffffff812b3b41>] ? _raw_read_unlock+0x23/0x27 [ 304.789686] [<ffffffffa0013e7f>] ? hci_send_to_sock+0x179/0x188 [bluetooth] [ 304.789686] [<ffffffffa00083d2>] hci_rx_task+0xc8/0x2f3 [bluetooth] [ 304.789686] [<ffffffff8102f5a9>] tasklet_action+0x87/0xe6 [ 304.789686] [<ffffffff8102fa11>] __do_softirq+0x9f/0x13f [ 304.789686] [<ffffffff8102fb33>] run_ksoftirqd+0x82/0x133 [ 304.789686] [<ffffffff8102fab1>] ? __do_softirq+0x13f/0x13f [ 304.789686] [<ffffffff81040f0a>] kthread+0x7f/0x87 [ 304.789686] [<ffffffff812b55c4>] kernel_thread_helper+0x4/0x10 [ 304.789686] [<ffffffff812b40d4>] ? retint_restore_args+0x13/0x13 [ 304.789686] [<ffffffff81040e8b>] ? __init_kthread_worker+0x53/0x53 [ 304.789686] [<ffffffff812b55c0>] ? gs_change+0x13/0x13 Signed-off-by: Andre Guedes <andre.guedes@openbossa.org> Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Diffstat (limited to 'net/bluetooth')
-rw-r--r--net/bluetooth/hci_core.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 270933523097..7ba1ca12c1d8 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1244,7 +1244,7 @@ int hci_blacklist_add(struct hci_dev *hdev, bdaddr_t *bdaddr)
if (bacmp(bdaddr, BDADDR_ANY) == 0)
return -EBADF;
- hci_dev_lock(hdev);
+ hci_dev_lock_bh(hdev);
if (hci_blacklist_lookup(hdev, bdaddr)) {
err = -EEXIST;
@@ -1264,7 +1264,7 @@ int hci_blacklist_add(struct hci_dev *hdev, bdaddr_t *bdaddr)
err = 0;
err:
- hci_dev_unlock(hdev);
+ hci_dev_unlock_bh(hdev);
return err;
}
@@ -1273,7 +1273,7 @@ int hci_blacklist_del(struct hci_dev *hdev, bdaddr_t *bdaddr)
struct bdaddr_list *entry;
int err = 0;
- hci_dev_lock(hdev);
+ hci_dev_lock_bh(hdev);
if (bacmp(bdaddr, BDADDR_ANY) == 0) {
hci_blacklist_clear(hdev);
@@ -1290,7 +1290,7 @@ int hci_blacklist_del(struct hci_dev *hdev, bdaddr_t *bdaddr)
kfree(entry);
done:
- hci_dev_unlock(hdev);
+ hci_dev_unlock_bh(hdev);
return err;
}